Defense Transportation: Air Mobility Command Needs to Collect and
Analyze Better Data to Assess Aircraft Utilization (29-SEP-05,
GAO-05-819).
Airlift is a flexible, but expensive, transportation method. From
September 2001 to April 2005, the Department of Defense (DOD) has
spent about $9.5 billion using airlift to transport equipment,
supplies, and troops for Operations Enduring Freedom (OEF) and
Iraqi Freedom (OIF). As of December 2004, airlift accounted for
about 13 percent of all cargo and passengers transported for
these operations. DOD has stated that high demand for available
airlift assets requires the department to use airlift assets as
efficiently as possible. However, DOD's primary objective
emphasizes delivering "the right items to the right place at the
right time" over using aircraft capacity as efficiently as
possible. Under the Comptroller General's authority, GAO sought
to determine whether DOD used capacity on strategic military
aircraft transporting cargo and passengers between the United
States and overseas theaters for OEF and OIF as efficiently as
possible.
-------------------------Indexing Terms-------------------------
REPORTNUM: GAO-05-819
ACCNO: A38657
TITLE: Defense Transportation: Air Mobility Command Needs to
Collect and Analyze Better Data to Assess Aircraft Utilization
DATE: 09/29/2005
SUBJECT: Airlift services
Data collection
Data integrity
Military aircraft
Military airlift operations
Military policies
Policy evaluation
Strategic planning
C-141 Aircraft
C-17 Aircraft
C-5 Aircraft
DOD Operation Iraqi Freedom
Galaxy Aircraft
Global Air Transportation Execution
System
Global War on Terrorism
Globemaster Aircraft
KC-10 Aircraft
KC-135 Aircraft
Operation Enduring Freedom
Starlifter Aircraft
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GAO-05-819
United States Government Accountability Office
GAO Report to the Secretary of Defense
September 2005
DEFENSE TRANSPORTATION
Air Mobility Command Needs to Collect and Analyze Better Data to Assess Aircraft
Utilization
a
GAO-05-819
[IMG]
September 2005
DEFENSE TRANSPORTATION
Air Mobility Command Needs to Collect and Analyze Better Data to Assess Aircraft
Utilization
What GAO Found
Because the Air Mobility Command (AMC), which is the Air Force agency
responsible for managing airlift, does not systematically collect and
analyze operational factors that impact payloads on individual missions,
DOD does not know how often it met its secondary goal to use aircraft
capacity as efficiently as possible. AMC collects data about short tons
transported and information about operational factors, such as weather and
runway length, when planning and executing airlift missions. AMC does not
capture data about these variables in a manner that allows officials to
determine historically whether aircraft capacity was used efficiently.
Historical mission planning files and the Global Air Transportation
Execution System that is used to track mission data could provide some
information about operational factors that affect mission payloads, but
limitations associated with these data sources do not allow officials to
determine whether DOD used aircraft capacity as efficiently as possible.
In the absence of data about operational factors that impact payloads on
specific missions, GAO calculated the average payloads for each type of
strategic aircraft and compared these to historical average payloads,
known as payload planning factors. GAO found that over 97 percent of C-5
missions and more than 81 percent of C-17 missions carried payloads below
DOD's payload planning factors, as shown in the table below. However,
because data on operational factors that impact payloads were not
available, GAO was not able to determine whether these payloads indicate
efficient use of aircraft capacity. Without adequate information about
operational variables and how these impact mission payloads, AMC officials
do not know the extent to which opportunities exist to use aircraft more
efficiently and whether operational tempo, cost, and wear and tear on
aircraft could be reduced. In addition, DOD officials do not have the
benefit of such analysis to determine future airlift requirements for
planning purposes.
Number and Percentage of Missions Below, Meeting, or Exceeding AMC's
Payload Planning Factors
Source: GAO analysis of DOD data.
Notes: This analysis does not consider operational factors used for
mission planning because data were not available. Although the C-130,
KC-10, and KC-135 are not considered strategic airlift aircraft, GAO has
included them in its analysis in those instances when AMC used these
aircraft in strategic airlift roles. Because C-5 aircraft have separate
compartments for passengers and cargo, we use a 71.5 payload planning
factor (the sum of the cargo and passenger payloads).
United States Government Accountability Office
Contents
Letter 1
Results in Brief 3
Background 4
The Extent to Which AMC Used Capacity as Efficiently as Possible
on Strategic Military Aircraft Cannot Be Readily Ascertained 7
Conclusions 15
Recommendations for Executive Action 16
Agency Comments and Our Evaluation 17
Appendixes
Appendix I: Scope and Methodology 20
Appendix II: Air Mobility Command Aircraft Used for 23
Strategic Airlift
Operational Factors That Can Affect Aircraft
Appendix III: Capacity
Utilized 29
Appendix IV: Comments from the Department of Defense 37
Appendix V: GAO Contact and Staff Acknowledgments 39
Tables Table 1: Payload Planning Factors and Allowable Cabin Loads for
Strategic Aircraft 7
Table 2: Load Message Utilization Data Field Codes and
Definitions 10
Table 3: Number and Percentage of Missions Below, Meeting, or
Exceeding Payload Planning Factors, by Plane Type,
October 2001 to September 2004 12
Table 4: Missions Carrying No Cargo and Not Meeting the Minimum
Requirements for Use of Strategic Airlift 13
Table 5: Payloads Transported by Type of Aircraft, October 2001
to
September 2004 15
Figures Figure 1:
Figure 2:
Figure 3:
Figure 4:
Figure 5:
Figure 6:
Figure 7:
Percentage of Cargo Transported by Sealift and Airlift for Operations
Enduring Freedom and Iraqi Freedom, September 2001 to December 2004 6 C-5
Aircraft 23 C-17 Aircraft 24 C-141 Aircraft 25 C-130 Aircraft 26 KC-10
Aircraft 27 KC-135 Aircraft 28
Contents
Figure 8: Unloading of a HH-60G Pave Hawk Helicopter from a
C-17 in Support of OIF 31 Figure 9: Loadmasters Chain Down Cargo on a C-17
32 Figure 10: Actual C-17 Load Plan Depicting How Placement of Cargo
Can Decrease Payloads 33 Figure 11: Actual C-17 Load Plan Depicting
Placement of Cargo to Accommodate Passengers 33
Abbreviations
AMC Air Mobility Command
DOD Department of Defense
GATES Global Air Transportation Execution System
OEF Operation Enduring Freedom
OIF Operation Iraqi Freedom
TRANSCOM United States Transformation Command
This is a work of the U.S. government and is not subject to copyright
protection in the United States. It may be reproduced and distributed in
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copyright holder may be necessary if you wish to reproduce this material
separately.
A
United States Government Accountability Office Washington, D.C. 20548
September 29, 2005
The Honorable Donald H. Rumsfeld Secretary of Defense
Dear Mr. Secretary:
When deploying forces overseas for the United States, the Department of
Defense (DOD) uses a variety of means to transport equipment, supplies,
and troops to a theater of operations, including rail, trucks, ships, and
aircraft. From September 30, 2001, through April 30, 2005, DOD spent more
than $19 billion to transport equipment, supplies, and troops in support
of the Global War on Terrorism, including Operations Enduring Freedom
(OEF) and Iraqi Freedom (OIF).1 Of this, DOD has spent about $9.5 billion
to transport equipment, supplies, and troops for OEF and OIF via airlift,
which is a fast and flexible, but expensive, transportation method
relative to sealift. At the end of December 2004, airlift accounted for
about 13 percent (464,239 short tons) of the more than 3.4 million short
tons transported via airlift and sealift for these operations.2 According
to U.S. Air Force doctrine, high demand for limited airlift assets
requires the department to use airlift as efficiently as possible while
still meeting combatant commanders' delivery time frames. Because DOD
emphasizes delivering the "right items to the right place at the right
time" for the warfighter, this doctrine states that meeting mission needs
is the Air Mobility Command's (AMC) primary objective, while the efficient
use of aircraft capacity is a secondary goal. Nevertheless, United States
Transportation Command (TRANSCOM) and AMC officials are looking for ways
to decrease costs and use aircraft capacity as efficiently as possible
while continuing to meet mission needs. These officials acknowledge that
they need information that helps decision makers understand whether
aircraft capacity was used efficiently while meeting mission needs,
especially when the pace of operations is high, and to plan for future
airlift transportation needs.
We conducted this review under the authority of the Comptroller General.
We sought to determine whether DOD used strategic military aircraft
efficiently during OEF and OIF. Specifically, our objective was to assess
1OEF began in October 2001 in Afghanistan and OIF began in March 2003 in
Iraq. 2A short ton is equivalent to 2,000 pounds.
the extent to which DOD used all available space and weight on these
aircraft when transporting equipment and supplies-hereafter referred to as
"cargo"-and passengers for OEF and OIF to the extent possible.
In performing our work, we reviewed applicable DOD guidance, interviewed
knowledgeable DOD officials, and analyzed AMC aircraft mission data. For
purposes of this report, we focused our review of strategic airlift
missions on contingency and special assignment airlift missions in support
of OEF and OIF.3 We excluded channel missions- scheduled flights over
established worldwide routes on government-owned or chartered aircraft
under the operational control of AMC that are used for cargo and troop
movements-because these occur on a regular schedule, and it is possible
that payloads would regularly be light. To obtain a better understanding
of operational factors, such as weather, fuel considerations, and aircraft
and airfield characteristics, that can impact payloads on individual
missions, we reviewed a limited number of historical mission planning
files for OEF and OIF and a Global Air Transportation Execution System
(GATES) data field that could provide some information about operational
factors on individual missions. However, limitations associated with these
data sources prevent using these for analysis to determine whether DOD
used aircraft capacity as efficiently as possible. In the absence of
reliable data about operational factors, we obtained and analyzed
strategic military airlift mission data for missions occurring from
October 1, 2001, to September 30, 2004, for the two operations to get an
indication of how well AMC utilized aircraft capacity. To determine
whether DOD used capacity on these aircraft as efficiently as possible, we
analyzed whether payloads transported for OEF and OIF met historical
average payloads, known as payload planning factors. We compared average
payloads transported by each aircraft type to the payload planning factors
for each aircraft type. We also assessed the reliability of these data by
reviewing existing documentation related to the data sources,
electronically testing the data to identify obvious problems with
completeness or accuracy, and interviewing knowledgeable agency officials
about the data. We determined the data were sufficiently reliable for
calculating average payloads transported on each type of aircraft.
However, data were not sufficiently available to determine how operational
3Contingency missions involve deployment, sustainment, and redeployment by
airlift. Special assignment airlift missions are aircraft operated to
satisfy a requirement needing special pickup or delivery at locations
other than those with regularly scheduled service or to satisfy a
requirement needing special consideration because of the number of
passengers, weight or size of the cargo, urgency, or sensitivity of
movement.
factors impacted payloads transported on individual missions. Without
information about operational factors that impacted payloads on these
airlift missions, we are unable to determine whether DOD used aircraft
capacity as efficiently as possible. We discussed our methodology with AMC
officials who agreed that such an analysis was appropriate. We conducted
our review from September 2004 through July 2005 in accordance with
generally accepted government auditing standards. A detailed description
of our scope and methodology is presented in appendix I.
Results in Brief Because the AMC does not systematically collect and
analyze operational factors that impact payloads on individual missions,
DOD does not know how often it met its secondary goal to use aircraft
capacity as efficiently as possible. According to U.S. Air Force doctrine,
high demand for limited airlift assets requires the department to use
airlift as efficiently as possible while still meeting combatant
commanders' delivery time frames. Although the AMC collects data about
short tons transported and information about operational factors, such as
weather and runway length, as it plans and executes airlift missions, the
command does not capture data about these factors in a manner that allows
officials to determine historically whether DOD used aircraft capacity as
efficiently as possible. Historical mission planning files and the Global
Air Transportation Execution System, a database that is used to track
mission data, could provide some information about operational factors
that impact mission payloads for individual missions. However, limitations
associated with these data sources-such as the completeness and format of
mission files and unknown accuracy of a Global Air Transportation
Execution System data field-prevent using these for analysis of aircraft
capacity used. Without information about operational factors that impacted
payloads on these airlift missions, we are unable to determine whether DOD
used aircraft capacity as efficiently as possible. In the absence of data
about operational factors that impact payloads on specific missions, we
calculated the average payloads for each type of aircraft and compared
these to payload planning factors-the historical average payloads
transported on each type of aircraft. Our analysis of 14,692 strategic
airlift missions flown in support of OIF and OEF showed that over 97
percent of C-5 missions and more than 81 percent of C-17 missions carried
payloads below the relevant payload planning factors for these types of
aircraft. Also, nearly 19 percent of the missions did not meet the minimum
requirements of 15 short tons or 100 passengers to qualify for use of
strategic airlift. However, AMC is required to provide airlift whenever
cargo and passengers are approved for
movement, even if minimum requirements for using strategic airlift are not
met or the requirement will not use an aircraft's available capacity as
efficiently as possible if this is the only way to accomplish the mission.
Given the absence of information about operational factors that could
explain why heavier payloads were not transported on specific missions,
command officials do not know the extent to which opportunities exist to
use aircraft capacity more efficiently. Potentially inefficient use of
aircraft could cause higher operational tempo and may increase costs as
well as wear and tear on aircraft. In addition, this lack of information
could cause DOD to understate or overstate future lift requirements for
planning purposes, and the right mix and number of aircraft may not be
available for future contingencies.
We are making recommendations to improve the department's collection and
analysis of information on operational factors that impact payloads
transported on aircraft used for strategic airlift. DOD provided written
comments on a draft of this report and concurred with each of our
recommendations. Based on DOD's written comments, we modified one
recommendation. DOD also provided technical comments on this report, and
we made changes where appropriate. We have reprinted DOD's comments in
appendix IV.
Background TRANSCOM, located at Scott Air Force Base, Illinois, is a
unified combatant command that provides air, land, and sea transportation
for DOD, both in peacetime and wartime.4 AMC, one of TRANSCOM's three
component commands, provides strategic airlift, among other services- such
as the Civil Reserve Air Fleet through which contracted commercial
aircraft support DOD airlift requirements in emergencies when the need for
airlift exceeds the capability of military aircraft-for deploying,
sustaining, and redeploying U.S. forces worldwide.5 Strategic airlift
moves cargo and passengers between the continental United States and
overseas theaters or between overseas theaters. AMC operates military
aircraft that constitute
4An unified combatant command is composed of forces from two or more
services and has a broad and continuing mission.
5TRANSCOM's other component commands are the Surface Deployment and
Distribution Command that is responsible for providing global surface
distribution services, and the Military Sealift Command that provides
ocean transportation of equipment, fuel, supplies and ammunition to
sustain U.S. forces worldwide.
the U.S. strategic airlift fleet, including the C-5, C-17, and C-141
aircraft (app. II describes each aircraft).6 In addition, AMC can use
aerial refueling aircraft, such as the KC-10 and KC-135, for transporting
cargo. Although the C-130 is primarily used for intratheater airlift
missions, AMC sometimes uses it in a strategic airlift role to transport
cargo from the United States to Iraq and Afghanistan, especially if the
aircraft is being moved into the theater and assigned to the United States
Central Command. AMC's Tanker Airlift Control Center plans, schedules, and
tracks tanker and airlift worldwide. The Fusion Cell, a division within
AMC's Tanker Airlift Control Center, was created following the terrorist
attacks of September 11, 2001, to provide senior decision makers with
information about the movement of air mobility assets, especially for
those missions associated with contingency operations. The Fusion Cell is
charged with collecting and analyzing cargo and passenger data from
completed missions using TRANSCOM- and AMC-owned and controlled databases,
such as the Global Transportation Network, GATES, and the Global Decision
Support System, and ensuring data quality.7
TRANSCOM uses the combatant commander's delivery date at the final
destination as well as information about the number and type of troops and
cargo-the requirement-needed to accomplish a specific mission to determine
the appropriate type of transportation needed to meet that date, develop
feasible transportation schedules for deploying forces, assign ports of
embarkation, and determine the best mode of transportation. AMC uses 15
short tons or 100 passengers as the minimum requirement for strategic
airlift and may combine cargo loads to meet this requirement. However, AMC
is required to provide airlift whenever cargo and passengers are approved
for movement even if minimum requirements for using strategic airlift are
not met or the requirement will not use an aircraft's available capacity
as efficiently as possible if this is the only way to accomplish the
mission. If airlift is required, TRANSCOM tasks AMC with assigning and
scheduling airlift. TRANSCOM reserves the use of airlift for
6The Air Force retired its C-141s from the active duty inventory in
September 2004. DOD plans to retire C-141s used by the Reserves and Air
National Guard before 2006.
7TRANSCOM's Global Transportation Network collects and integrates
information from a number of transportation systems to support
transportation planning and decision-making. GATES provides AMC with
automated capability to process and track cargo and passenger airlift data
and facilitates payment for services. AMC's Global Decision Support System
provides aircraft schedules, arrival and departure, and aircraft status
data to support intransit visibility of aircraft and aircrews.
(1) short notice and emergency requirements, (2) intelligence-related or
sensitive cargo, and (3) when operational security considerations preclude
the use of sealift. AMC assigns aircraft to move cargo and passengers
based on (1) mission urgency and sensitivity, (2) cargo and passenger
characteristics, and (3) other special factors. Currently, DOD transports
the majority of cargo by sealift, as shown in figure 1.
Figure 1: Percentage of Cargo Transported by Sealift and Airlift for
Operations Enduring Freedom and Iraqi Freedom, September 2001 to December
2004 Percentage 100 97.51
90
80
70
60
50
40
30
20
10
0 2001 2002 2003 2004 Year
Airlift
Sealift Source: GAO analysis of DOD data.
AMC officials use the average historical payload transported on each type
of aircraft (see table 1), known as payload planning factors, to develop
broad estimates of the types and number of aircraft initially needed to
meet mission requirements. The payload planning factors are generally less
than the maximum payload capacity, including the weight of unit personnel,
equipment, and material that an aircraft can carry, known as the allowable
cabin load.
Table 1: Payload Planning Factors and Allowable Cabin Loads for Strategic
Aircraft
In short tons
Payload planning factor
Aircraft type Cargo Passenger Allowable cabin load
C-5 61.3 10.2
C-17 45.0 18.0
C-130 12.0 16.0
C-141 19.0 24.0
KC-10 32.6 13.6
KC-135 13.0 9.2
Source: United States Air Force.
Notes: The payload planning factor assumes loads contain only cargo or
only passengers, not a mixture. For all aircraft types except the C-5,
mixed loads usually would have payload planning factors in between the
cargo and passenger payloads listed above. Because C-5s have separate
compartments for passengers and cargo, the mixed payload planning factor
would be the sum of the cargo and passenger payloads (71.5 short tons).
Although the C-130, KC-10, and KC-135 are not considered strategic airlift
aircraft, we have included them in our analysis in those instances when
AMC used these aircraft in strategic airlift roles.
The Extent to Which AMC Used Capacity as Efficiently as Possible on
Strategic Military Aircraft Cannot Be Readily Ascertained
Because AMC does not systematically collect and analyze operational
factors that impact payloads on individual missions, DOD does not know how
often it met its secondary goal to use aircraft capacity as efficiently as
possible. Historical mission planning files have limitations that prevent
DOD officials from using the files to determine whether AMC used aircraft
efficiently. In addition, data on operational factors captured in the
GATES database are not useful because codes that could provide AMC
officials with information about why aircraft flew with the payloads they
did are neither well-defined nor comprehensive, and the accuracy and
reliability of the data cannot be determined. In the absence of data about
operational factors that impact payloads on individual missions, we
calculated the average payloads for each type of strategic aircraft and
compared these to the payload planning factors. Our analysis of AMC data
showed that more than 86 percent of these missions flew with payloads that
were lighter than established payload planning factors, and some of these
did not meet the minimum requirement of 15 short tons or 100 passengers
needed to qualify for use of strategic airlift. However, because AMC lacks
data to determine how operational factors impact payloads, we are not able
to determine whether these payloads indicate efficient use of an
aircraft's capacity.
Historical Mission Planning Files Have Limitations That Prevent Their Use
to Determine Whether AMC Used Aircraft Capacity as Efficiently as Possible
Historical mission planning files identify mission data and operational
factors that may impact aircraft payloads, but we found limitations with
using these files to determine whether AMC used an aircraft's capacity as
efficiently as possible. We reviewed 25 historical mission planning files
for OEF and OIF to gain an understanding of how operational factors could
impact payloads. We found these files were not retained in a format that
facilitates manipulation of data for analysis to determine whether an
aircraft's capacity was used efficiently, and the files were not always
complete or accurate. Although the historical mission planning files
contain some information that could help identify operational factors that
impacted aircraft payloads, the data are not easy to manipulate for
analysis because the historical mission planning files are paper based.
Currently, AMC stores the files in binders and boxes categorized by the
operation, such as OEF, and the month and year of the flight. Officials
told us that this organization system makes it difficult to access data
for specific missions.
We also found that some of the files we reviewed were incomplete or
inaccurate. For instance, 3 of the 25 mission files we reviewed were
missing load plans that AMC officials use to identify appropriate aircraft
with which to transport cargo and passengers. According to a command
official, time constraints, among other factors, can impact whether load
plans were sent to AMC. An official told us that units sometimes make
changes to the load plans and do not inform AMC, which could cause
aircraft to be underutilized if the allowable cabin load of the available
and scheduled aircraft is too large for the size and weight of the
requirement to be moved. AMC officials did not provide data on the
frequency with which units make such changes. However, because of concerns
about the accuracy of load plans, especially from units that do not deploy
frequently, AMC officials told us that they always call units before
scheduling aircraft to request load plans and confirm the accuracy of
validated Time Phased Force and Deployment Data that identify the forces,
sequence, and priority of unit deployments; the locations of ports of
debarkation for a specific unit; and the number of pieces of cargo, cargo
dimensions, and numbers and weights of passengers.
Despite these limitations, the mission planning files are the only
combined source of mission information that includes load plans,
diplomatic clearances, and air refueling requests and shows what was
planned to be transported on an aircraft used for OEF and OIF. An AMC
official told us that the historical mission planning files capture
operational data that could be valuable for helping DOD understand the
implications of moving
to a lighter and faster force and projecting airlift assets needed to
transport this force.
One AMC Database Is Also Not Useful for Assessing Whether Aircraft
Capacity Was Used as Efficiently as Possible
Operational data captured in one of AMC's databases, GATES,-the "system of
record" database that provides AMC with automated capability to process
and track cargo and passenger airlift data and facilitates payment for
services-is also not useful for assessing whether AMC used an aircraft's
capacity as efficiently as possible. When GATES was automated in 2000,
command officials retained a data field called "Load Message Utilization"
that consists of 13 codes that could provide AMC officials with
information about why an aircraft flew with the payloads it did. AMC
requires GATES users to manually enter a primary and, if relevant, a
secondary code from the 13 codes presented in table 2 before transmitting
mission data to AMC, although the command does not review or use this
information for analysis.
Table 2: Load Message Utilization Data Field Codes and Definitions
Code
A Pallet positions or seats not fully used due to substitute aircraft that
provided more pallet positions or seats than the aircraft originally
scheduled.
B Excess seats. Scheduled or programmed passenger airlift capability in
excess to station requirements.
Gained from previous station. All programmed seats used. Additional
capability available to an en route station due to previous stations not
using allocated seats.
D Late passenger cancellations or no-show passengers.
E Insufficient processed or palletized cargo on hand for downline
stations, including cargo for other destinations that is authorized to be
transshipped at downline stations (to be used if sufficient cargo is in
the port, but not yet processed or movement ready).
F Low port level. Insufficient cargo in port (both processed and
unprocessed), for downline stations, including cargo for other
destinations which is authorized to be transshipped at downline stations.
G Additional crew members. Used when additional crew members preclude use
of installed passenger seats or pallet positions.
H Unsuitable cargo. Hazardous or other special handling cargo which
precludes optimum utilization of cargo space or passenger seats.
J Light pallets or cargo. All pallet positions used, but allowable cabin
load not fully utilized due to light pallets or rolling stock or pallets
with overhang which precludes full utilization of space.
K Space block. Space not fully used due to passenger or cargo space blocks
for downline stations.
Aircraft fully utilized, cargo mission only. Used when the percent
utilized is 95 to 100 percent. Use the following formula:
Payload/Allowable cabin load x 100 = percent utilized.
W Aircraft fully utilized, passenger missions only. Used when 95 percent
or more of available passenger seats were used for space required (duty)
passengers.
Z No other code applies. Provide short explanation in remarks.
Source: GATES Data Dictionary.
Although command officials could use some information captured in the
"Load Message Utilization" data field to understand why aircraft flew with
specific payloads, codes in this data field are neither well defined nor
comprehensive, and the accuracy and reliability of the data are not known.
There may be similar data fields in other transportation information
systems such as the Global Transportation Network and Global Decision
Support System that could be used to capture operational data. However, we
are unaware of similar fields in these databases that could be modified
for this use.
According to AMC officials, some of the codes are not well defined and are
inconsistently interpreted and applied by users. For example, the "V" code
indicates that the aircraft is considered fully utilized only if the
payload is 95 to 100 percent of the allowable cabin load. However, as we
previously reported, an aircraft may be fully utilized with lighter
payloads if the maximum volume of cargo that will fit into an aircraft is
reached before the maximum cargo weight is reached.8 AMC officials told us
that most airlifted cargo loads reach maximum volume before reaching
maximum weight. Additionally, an AMC official who reviewed the "Load
Message Utilization" codes believes that users may have inappropriately
applied the codes. We were not able to determine the extent to which users
may have done this because we could not determine the reliability of data.
We also found that the codes are not as comprehensive as they could be.
For example, there are no codes to indicate that an aircraft was fully
utilized because the maximum volume of cargo that could fit into the
aircraft was reached before the maximum cargo weight was reached. In
addition, there are no codes that indicate if payloads were decreased to
accommodate poor weather conditions; airfield characteristics, such as
short runways; or aircraft characteristics, such as structural fatigue.
Finally, no codes identify whether an aircraft's capacity was
underutilized because the only available aircraft was too large for the
size and weight of the requirement to be moved within the time frame
required. Although GATES users could enter such information using the "Z"
code and associated remarks, this would not guarantee consistent remarks
or allow for AMC officials to manipulate these data for analysis.
Finally, we were unable to assess the reliability or accuracy of "Load
Message Utilization" data. Although the Chairman of the Joint Chiefs of
Staff Manual recognizes that data quality is directly linked to data
collection and entry at the port of embarkation and requires appropriate
commander emphasis to ensure accuracy, aerial port supervisors are not
required to review the "Load Message Utilization" code for accuracy prior
to transmission to AMC. AMC officials told us that although they require
this data field to be completed by users, AMC does not use this
information and officials do not verify or validate the data entered in
this data field. According to AMC officials, GATES users frequently use
the "Z" code (no other code applies) as a placeholder.
8GAO, C-17 Globemaster: Support of Operation Joint Endeavor, GAO-97-50
(Washington, D.C.: Feb. 14, 1997).
Analysis of AMC Data Showed That a Significant Number of Strategic Airlift
Missions Flew with Payloads Lighter Than Established Planning Factors
Our analysis of 14,692 strategic airlift missions for OEF and OIF showed
that more than 86 percent flew with payloads that were lighter than
established payload planning factors; nearly 19 percent did not meet the
minimum requirements of 15 short tons or 100 passengers needed to qualify
for use of strategic airlift; and average payloads for strategic airlift
missions were less than historical average payloads. For example, we found
that over 97 percent of missions on C-5 aircraft, nearly 98 percent of
missions on C-130 aircraft, and 80 percent of missions on KC-135 aircraft
had payloads that were below the payload planning factors for these types
of aircraft, as shown in table 3. In contrast, almost 19 percent of C-17
missions, about 18 percent of KC-10 missions, and 26 percent of C-141
missions met or exceeded the relevant payload planning factors.
Table 3: Number and Percentage of Missions Below, Meeting, or Exceeding
Payload Planning Factors, by Plane Type, October 2001 to September 2004
Type of aircraft
Number of missions
Payload planning factor (in short tons)
Number of missions below the payload planning factor Percentage of
missions below the payload planning factor Number of missions meeting or
exceeding the payload planning factor Percentage of missions meeting or
exceeding the payload planning factor
C-5 4,425 71.5 4,305 97.3 120 2.71
C-17 8,909 45.0 7,263 81.5 1,646 18.5
C-130 551 12.0 539 97.8 12
C-141 511 19.0 378 74.0 133
KC-10 186 32.6 152 81.7 34
KC-135 110 13.0 88 80.0 22
Total 14,692 12,725 1,967
Source: GAO analysis of DOD data.
Notes: This analysis does not consider operational factors used for
mission planning because data were not available. Although the C-130,
KC-10, and KC-135 are not considered strategic airlift aircraft, we have
included them in our analysis in those instances when AMC used these
aircraft in strategic airlift roles. Because C-5 aircraft have separate
compartments for passengers and cargo, we use a 71.5 payload planning
factor (the sum of the cargo and passenger payloads) rather than the 61.3
short tons published in Air Force Pamphlet 10-1403. For a C-5 aircraft to
be fully utilized, DOD would need to fully utilize available space in both
the cargo and passenger compartments.
However, because AMC lacks data to determine how operational factors
impact payloads (see app. III for details on some of these factors), we
are not able to determine whether these payloads indicate efficient use of
an aircraft's capacity.
Our analysis also showed that about 4 percent (524) of strategic airlift
missions carried no cargo and nearly 19 percent (2,734) of all strategic
airlift missions transporting cargo and passengers for OEF and OIF did not
meet the minimum requirements for use of strategic airlift, resulting in
light payloads and, potentially, underutilization of aircraft (see table
4). Missions that did not meet minimum requirements for strategic airlift
carried an average of about 5 short tons of cargo and 26 passengers.
Table 4: Missions Carrying No Cargo and Not Meeting the Minimum Requirements for
Use of Strategic Airlift Operation Enduring Freedom Operation Iraqi Freedom
Number of missions Number of
not missions not
Number of meeting minimum Number of meeting minimum
Type of Number of missions requirement for missions requirement for
with strategic with strategic
aircraft missions no cargo airlift no cargo airlift
C-5 4,425 49 123 21 131
C-17 8,909 185 1,175 36 468
C-130 551 80 48 112
C-141 511 4 175 6
KC-10 186 2 20 3
KC-135 110 21 46 5
Total 14,692 341 1,587 183 1,147
Source: GAO analysis of DOD data.
Note: Although the C-130, KC-10, and KC-135 are not considered strategic
airlift aircraft, we have included them in our analysis in those instances
when AMC used these aircraft in strategic airlift roles.
However, because AMC lacks data to determine how operational factors
impact payloads, we are not able to determine whether these payloads
indicate efficient use of an aircraft's capacity.
Although aerial port officials may know why individual flights flew empty
or with light payloads, AMC does not collect these data, and available
data collected by AMC were not sufficient to determine why this occurred.
AMC officials told us that data show that some aircraft flew empty,
possibly because the command tracks mission data for aircraft without
cargo on board that were moved into the theater and assigned to the United
States Central Command. According to these officials, the lack of
technology at austere locations also prevents capturing mission data,
including payloads transported. AMC officials further explained that
although their databases also track classified missions, they do not
capture payloads or other data for these missions.
There may be legitimate reasons why AMC flew missions that did not meet
minimum requirements for the use of strategic airlift. For instance,
aircraft transporting light but bulky cargo could have light payloads.
Charleston Air Force Base officials told us that they had transported
rolls of bubble wrap to package Patriot missiles for return to the United
States by airlift. For this mission, the payload was light, but the
aircraft was fully utilized because the rolls used all available locations
where cargo can be placed. AMC officials also told us that they attempt to
use capacity as efficiently as possible by scheduling an aircraft that is
sufficient for the size and weight of the requirement to be moved,
scheduling en route stops to consolidate smaller loads, and negotiating
delivery dates when possible. However, unlike commercial cargo carriers
such as Federal Express, AMC officials cannot decline to deliver a
customer's order if it does not fully utilize the aircraft. AMC is
required to provide airlift whenever cargo and passengers are approved for
movement even if minimum requirements for using strategic airlift are not
met or the requirement will not fully utilize an aircraft's available
capacity. A command official also told us that DOD guidance permits the
use of strategic airlift even if the minimum requirements of 100
passengers or 15 short tons of cargo are not met if this is the only way
to accomplish the mission. Therefore, AMC may fly aircraft with reduced
payloads in order to meet combatant commanders' delivery time frames.
While we believe this may cause aircraft to be underutilized, AMC
officials emphasized that the command's primary objective is to deliver
"the right items to the right place at the right time" and that optimizing
capacity is a secondary goal. Furthermore, according to a command
official, DOD established these minimum requirements as a way to identify
large enough loads to justify sending a C-141 or C-17 aircraft to complete
a mission.
However, without information about operational factors that impacted the
payloads on these airlift missions, we are unable to determine whether DOD
used an aircraft's capacity as efficiently as possible. In the absence of
such data, we calculated the average payloads for each type of aircraft
and compared these to relevant payload planning factors to get an
indication as to how well AMC utilized aircraft. We found that aircraft
payloads for OEF and OIF were, on average, less than historical average
payloads. Table 5 shows the average payloads transported for both OEF and
OIF by each type of strategic aircraft and how they compare to each
aircraft's payload planning factor.
Table 5: Payloads Transported by Type of Aircraft, October 2001 to September
2004
In short tons
Type of Average payload for Operation
Average payload for Average payload for Payload planning
aircraft
Enduring Freedom Operation Iraqi Freedom both operations factor
47.8 48.0 47.9 71.5a
C-17 27.5 29.8 28.3 45.0
C-130 4.5 5.4 5.0
C-141 15.7 16.6 16.5
KC-10 12.9 17.9 17.3
KC-135 6.5 7.6 6.9
Source: GAO analysis of DOD data.
Note: Although the C-130, KC-10, and KC-135 are not considered strategic
airlift aircraft, we have included them in our analysis in those instances
when AMC used these aircraft in strategic airlift roles.
aThe payload planning factor assumes loads contain only cargo or only
passengers, not a mixture. For all aircraft types except the C-5, mixed
loads usually would have payload planning factors in between the cargo and
passenger payloads listed in table 1. Because C-5s have separate
compartments for passengers and cargo, the mixed payload planning factor
would be the sum of the cargo and passenger payloads (71.5 short tons).
Because AMC lacks data to determine how operational factors impact
payloads, we are not able to determine whether these payloads indicate
efficient use of an aircraft's capacity.
In general, in the absence of information about operational factors that
could explain why heavier payloads were not transported, command officials
do not know whether and where opportunities existed to use an aircraft's
capacity more efficiently or if there is the opportunity to reduce
operational tempo, costs, and wear and tear on aircraft. By not collecting
information about and analyzing the factors that impact aircraft capacity
utilized, DOD officials could also be understating lift requirements for
planning purposes, and the right mix and number of aircraft may not be
available for future contingencies.
Conclusions Because DOD emphasizes delivering the "right items to the
right place at the right time" over the efficient use of an aircraft's
capacity, AMC has a reason for underutilizing aircraft capacity on some
missions. However, we believe that AMC officials need more data about
operational factors, which can also impact aircraft capacity, and that
these data need to be maintained in a manner allows officials to determine
whether DOD used an aircraft's capacity as efficiently as possible.
Furthermore, we believe it is important
that reliable and complete data are collected to allow DOD and the
Congress to make informed decisions about future airlift requirements. We
have reported that a key factor contributing to the usefulness of data is
the degree to which officials are confident that information is credible.9
Useful practices for helping decision makers assess the quality and value
of data include assessing the reliability and verifying and validating
data to ensure that they adequately represent actual performance. Such
data could help officials make informed decisions about the capacity of
aircraft utilized when transporting cargo on strategic missions as well as
planning for future strategic lift requirements. Because they do not
collect information about and analyze the factors that impact payloads,
DOD officials do not have adequate information about aircraft capacity and
do not know whether capacity is utilized to the maximum extent possible.
Potentially inefficient use of aircraft capacity could cause higher
operational tempo and may increase cost as well as wear and tear on
aircraft. In addition, this lack of information could cause DOD to
understate or overstate future lift requirements for planning purposes,
and the right mix and number of aircraft may not be available for future
contingencies.
Recommendations for Executive Action
To help officials determine whether they used an aircraft's capacity as
efficiently as possible and improve the reliability and completeness of
data on operational factors that can impact payloads, we recommend that
the Secretary of Defense direct the Secretary of the Air Force to direct
the Commander, Air Mobility Command, to take the following two actions:
o Revise and clarify relevant data fields in GATES, and work with DOD
entities that support other transportation information systems, such as
the Global Transportation Network and service deployment systems, to
capture comprehensive, well-defined data on operational factors that
impact payloads for individual missions, and require supervisors to review
these data fields for accuracy. These factors include-but are not limited
to-number of pallet positions used, cargo dimensions, fueling decisions,
and altitude constraints.
o Systematically collect and analyze information on operational factors
that impact payloads transported on strategic airlift missions to identify
9GAO, Defense Management: Tools for Measuring and Managing Defense Agency
Performance Could Be Strengthened, GAO-04-919 (Washington, D.C.: Sept. 13,
2004).
ways that DOD may be able to use an aircraft's capacity as efficiently as
possible.
Agency Comments and Our Evaluation
DOD's comments are reprinted in appendix IV. In commenting on a draft of
this report, DOD concurred with both recommendations. It also provided
technical comments, which we included in the report as appropriate.
DOD concurred with our recommendation to revise and clarify GATES data
fields to capture a more comprehensive, well-defined list of operational
factors that impact payloads for individual missions. In concurring with
our recommendation, DOD made two additional comments. First, DOD noted
that some contingency missions are often processed through service
deployment systems and that other systems are also used to collect data
regarding aircraft utilization. We agree with DOD that contingency
missions are processed through systems other than GATES. However, as noted
in our report, we used data on completed missions obtained from the Tanker
Airlift Control Center's Fusion Cell database, which compiles and
validates data obtained from GATES as well as the Global Transportation
Network and the Global Decision Support System. AMC officials agreed with
this methodology and these sources for our analysis. Second, DOD stated
that data shortfalls are not only in GATES and that data such as altitude
constraints, fueling decisions, and other operational decisions conducted
outside the aerial ports do not belong in GATES. We agree with DOD that
GATES is not a full-spectrum airfield and airlift planning and execution
system, and that GATES may not be the only system that could capture the
necessary information needed for a more comprehensive analysis of aircraft
utilization. During the course of this review, we were not made aware of
data fields in other information systems that captured information similar
to the "Load Message Utilization" field in GATES. As a result, we focused
our recommendation on GATES to identify how improvements could be made to
transportation information systems to capture data on operational factors
that could provide a more comprehensive picture of how well AMC and the
combatant commanders are utilizing aircraft. In response to DOD's
comments, we also reviewed user guides and data dictionaries for these
other systems and identified a number of data fields that could provide
additional operational data. However, in further discussions, DOD
officials told us that data in these fields are not always easily
accessible or complete and reliable. Therefore, to recognize that there
may be other systems that could also be used to capture operational data,
we have revised our recommendation for DOD to
revise and clarify data fields in GATES and any other transportation
information systems.
DOD concurred with our second recommendation to systematically collect and
analyze information on operational factors that impact payloads
transported on strategic airlift missions and stated that AMC's Tanker
Airlift Control Center already collects and analyzes mission data from
several transportation information systems, including allowable cabin load
utilization by aircraft type. As noted in our scope and methodology, for
our analysis of aircraft utilization we used data obtained from the Tanker
Airlift Control Center's Fusion Cell database, which compiles data
obtained from GATES as well as the Global Transportation Network and the
Global Decision Support System. However, this database did not include the
operational data we believe is needed by DOD to analyze and better
understand how operational factors impact these payloads, to determine
whether all available space and weight on these aircraft was used in light
of such operational factors, and to plan for future airlift transportation
needs.
DOD also stated that any audit of contingency aircraft utilization must
include the Time Phased Force Deployment Data validation process. We
acknowledge that this process plays an integral role in determining what
needs to be moved and how it is moved. However, our objective was to
determine how efficiently AMC utilized its airlift assets after that
validation process is completed; therefore, the process is outside of the
scope of our review. As we discuss in the background and appendix III, AMC
is required to provide airlift whenever cargo and passengers are approved
for movement even if minimum requirements for using strategic airlift are
not met or the requirement will not use an aircraft's available capacity
as efficiently as possible, if this is the only way to accomplish the
mission. This means that if a combatant commander puts forward a
requirement through the Time Phased Force Deployment Data validation
process and it is designated by TRANSCOM for airlift, AMC will fly the
mission, even if it does not meet the minimum requirements or allow the
most efficient use of capacity.
As you know, 31 U.S.C. S: 720 requires the head of a federal agency to
submit a written statement on actions taken to address our recommendations
to the Senate Committee on Governmental Affairs and the House Committee on
Government Reform not later than 60 days after the date of this report. A
written statement must also be submitted to the House and Senate
Committees on Appropriations with the agency's first
request for appropriations made more than 60 days after the date of this
report.
We are sending copies of this report to interested congressional
committees; the Secretaries of the Army, the Navy, and the Air Force; the
Commandant of the Marine Corps; and the Director, Office of Management and
Budget. We will make copies available to others upon request. In addition,
the report will be available at no charge on the GAO Web site at
http://www.gao.gov.
If you or your staff have any questions regarding this report, please
contact me at (202) 512-5140 or [email protected]. Contact points for our
Offices of Congressional Relations and Public Affairs may be found on the
last page of this report. GAO staff who made major contributions to this
report are listed in appendix V.
Sincerely yours,
William Solis Director, Defense Capabilities and Management
Appendix I
Scope and Methodology
To assess the extent to which the Department of Defense (DOD) used an
aircraft's capacity as efficiently as possible while transporting cargo
and passengers for Operations Enduring Freedom (OEF) and Iraqi Freedom
(OIF), we reviewed relevant DOD guidance and defense transportation
regulations and interviewed knowledgeable officials from the following
offices, commands, and services:
o 13th Corps Support Command, Fort Hood, Killeen, Texas.
o 3rd Army Corps, Directorate of Logistics, Fort Hood, Killeen, Texas.
o 437th Aerial Port Squadron, Charleston Air Force Base, South Carolina.
o 4th Infantry Division, Fort Hood, Killeen, Texas.
o 819th Rapid Engineer Deployable Heavy Operational Repair Squadron
Engineer, Malmstrom Air Force Base, Montana.
o Air Mobility Command (AMC), Scott Air Force Base, Illinois.
o I Marine Expeditionary Force, Camp Pendleton, California.
o II Marine Expeditionary Force, Camp Lejeune, North Carolina.
o Joint Chiefs of Staff, Joint Staff Logistics Directorate, Arlington,
Virginia.
o Office of the Secretary of Defense, Program Analysis and Evaluation,
Arlington, Virginia.
o United States Central Command, MacDill Air Force Base, Tampa, Florida.
o United States Joint Forces Command, Norfolk, Virginia.
o United States Army Forces Command, Fort McPherson, Georgia.
o United States Army Installation Management Agency, Arlington, Virginia.
o United States Transportation Command, Scott Air Force Base, Illinois.
Appendix I Scope and Methodology
To gain an understanding of how operational realities can affect aircraft
payloads, we reviewed a limited number of historical mission planning
files. The files that we reviewed were sometimes missing load plans that
would assist in explaining operational factors that may have impacted
payloads. When load plans were present in the mission files, AMC officials
were able to identify a number of factors that could plausibly impact
mission payloads; however, they could not be certain that these factors
did impact payloads when the mission was executed. We also reviewed
information about the "Load Message Utilization" data field in the Global
Air Transportation Execution System and discussed the reliability and
accuracy of these data with AMC and aerial port officials. We determined
that this data field was not sufficiently reliable for this purpose. We
also met with officials concerning AMC's Global Transportation Network and
Global Decision Support System.
We limited our review of airlift missions to strategic contingency
missions and special assignment airlift missions for the Army, Navy, Air
Force, and Marine Corps as well as joint missions flown on AMC-owned and
AMC-operated aircraft in support of OEF and OIF. The U.S. strategic
airlift fleet includes the C-5, C-17, C-130, and C-141 aircraft. Because
aerial refueling aircraft, such as the KC-10 and KC-135, are also capable
of transporting cargo for strategic airlift missions, we also included
these aircraft in our analyses. We initially obtained mission data for
37,622 airlift missions1 occurring from October 1, 2001, to September 30,
2004 from AMC's Fusion Cell.
Because we focused on strategic missions, we excluded intratheater
missions from our analyses. In addition, we excluded channel missions-
regularly scheduled flights on government-owned or chartered aircraft
under the operational control of AMC that are used for cargo and troop
movements-because these occur on a regular schedule, and it is possible
that payloads would regularly be light. We also excluded missions on
commercial aircraft because these are not owned by AMC. By applying our
selection criteria identified earlier, we narrowed the number of missions
that we reviewed to 14,692. To assess the reliability of these data, we
(1) reviewed existing documentation related to the data sources,
1When selecting missions to analyze, we used the mission leg with the
greatest short tons on board, including passenger weight. The
approximately 170,000 mission legs that AMC flew during this time frame
resulted in 37,622 unique missions prior to application of our selection
criteria. Based on discussions with Fusion Cell staff clarifying our
analysis results, we eliminated 6 missions from our analysis that showed
improbably high payloads.
Appendix I Scope and Methodology
(2) electronically tested the data to identify obvious problems with
completeness or accuracy, and (3) interviewed knowledgeable agency
officials about the data. We determined that the Fusion Cell's data were
sufficiently reliable to summarize the actual cargo and passenger
payloads. We then compared Fusion Cell average payload data for OEF and
OIF strategic aircraft with payload planning factors and determined
whether payloads for OEF and OIF met the payload planning factors. We also
calculated the average total short tons transported on each type of
aircraft, and determined the percentage of aircraft that carried short
tons in excess as well as below the payload planning factors.
Additionally, we determined the number of missions that did not meet the
minimum strategic airlift requirements of 15 short tons or 100 passengers.
DOD guidance permits the use of strategic airlift even if minimum payload
and passenger requirements are not met if this is the only way to
accomplish the mission. Furthermore, AMC is required to provide airlift
whenever cargo and passengers are validated for movement even if the
minimum requirement to use strategic airlift is not met. However, we were
not able to determine the reasons why the minimum requirement was waived
for nearly 19 percent of all missions we reviewed. We also identified a
number of missions that carried no cargo or passengers; however, we were
not able to identify all of the reasons why these aircraft flew empty.
We conducted our review from September 2004 through July 2005 in
accordance with generally accepted government auditing standards.
Appendix II
Air Mobility Command Aircraft Used for Strategic Airlift
The AMC is responsible for providing global airlift services and air
refueling operations. To carry out its mission, the command has a
strategic airlift fleet comprised of the C-5, C-17, and C-141. In
addition, AMC can use aerial refueling aircraft, such as the KC-10 and
KC-135, for transporting cargo. Although the C-130 is primarily used for
intratheater airlift missions, AMC sometimes uses it in a strategic
airlift role to transport cargo from the United States to Iraq and
Afghanistan, especially if the aircraft is being moved into the theater
and assigned to the United States Central Command. This appendix briefly
describes these aircraft (figs. 2 through 7 are photographs of the various
aircraft).
C-5 Aircraft
Figure 2: C-5 Aircraft
Source: DOD.
The C-5 is one of the largest aircraft in the world. It can carry outsize
and oversize cargo over intercontinental ranges and can take off or land
in relatively short distances. A C-5 with a cargo load of 135 short tons
can fly 2,150 nautical miles, off-load, and fly to a second base 500
nautical miles away from the original destination without aerial
refueling. With aerial refueling, the aircraft's range is limited only by
crew endurance. The C-5 can carry nearly all of the Army's combat
equipment, including large heavy items such as the 74-ton mobile scissors
bridge. Ground crews can load and off-load the C-5 simultaneously at the
front and rear cargo openings. The landing gear system permits lowering of
the parked aircraft so the cargo
Appendix II Air Mobility Command Aircraft Used for Strategic Airlift
floor is at truck bed height or to facilitate vehicle loading and
unloading. The aircraft length is about 247 feet, its height is
approximately 65 feet, and its wing span is about 223 feet.
C-17 Aircraft
Figure 3: C-17 Aircraft
Source: DOD.
The C-17 aircraft is capable of transporting substantial payloads over
long ranges without refueling. The C-17 is intended to deliver cargo and
troops directly to forward airfields near the front lines or to main
operating bases; fly into small, austere airfields; land on short runways;
transport outsize cargo, such as tanks; and air-drop troops and equipment.
The C-17 can take off and land on runways as short as 3,000 feet long and
90 feet wide. With a payload of 80 short tons and an initial cruise
altitude of 28,000 feet, the C-17 has an unrefueled range of approximately
2,400 nautical miles. The aircraft length is 174 feet, its height is about
55 feet, and its wing span is almost 170 feet. The C-17 will be AMC's
primary military airlift aircraft once the C-141s are retired from
service.
Appendix II Air Mobility Command Aircraft Used for Strategic Airlift
C-141 Aircraft
Figure 4: C-141 Aircraft
Source: DOD.
The C-141 was AMC's first jet aircraft designed to meet military standards
as a troop and cargo carrier, and is used to airlift combat forces over
long distances, deliver those forces and their equipment either by landing
or airdrop, resupply forces, and transport the sick and wounded from a
hostile area to medical facilities. The aircraft length is approximately
168 feet, its height is about 39 feet, and the wing span is 160 feet. The
Air Force retired its C-141s from the active duty inventory in September
2004 and began transferring C-141s to the Air Reserve and Air National
Guard forces in July 1986. DOD plans to retire C-141s used by the Air
Reserves and Air National Guard before 2006.
Appendix II Air Mobility Command Aircraft Used for Strategic Airlift
C-130 Aircraft
Figure 5: C-130 Aircraft
Source: DOD.
The C-130 is the primary transport aircraft for air-dropping troops and
equipment into hostile areas. Other roles include airlift support,
Antarctic ice resupply, and aeromedical missions. Using its aft loading
ramp and door, the C-130 can accommodate oversized cargo, including
utility helicopters and six-wheeled armored vehicles, as well as standard
palletized cargo and military personnel. Additionally, the C-130 can be
rapidly reconfigured for various types of cargo, such as palletized
equipment, floor-loaded material, airdrop platforms, container delivery
system bundles, vehicles and personnel, or aeromedical evacuation. In an
aerial delivery role, it can airdrop loads up to 21 short tons or use its
high-flotation landing gear to land and deliver cargo on rough, dirt
strips. The C-130 has a length of about 97 feet, a height of approximately
38 feet, and a wing span of about 132 feet. Depending on the aircraft
model, the C-130 can carry a maximum of 6 to 8 pallets, 92 to 128 combat
troops, or a combination of any of these up to the cargo compartment
capacity or maximum allowable weight.
Appendix II Air Mobility Command Aircraft Used for Strategic Airlift
KC-10 Aircraft
Figure 6: KC-10 Aircraft
Source: DOD.
Although the KC-l0's primary mission is aerial refueling, it can combine
the tasks of a tanker and cargo aircraft by refueling fighters and
simultaneously carrying the fighter support personnel and equipment on
overseas deployments. The KC-10 can transport up to 75 people and nearly
85 short tons of cargo a distance of about 4,400 miles without refueling.
The large cargo-loading door can accommodate most Air Forces fighter unit
support equipment. Powered rollers and winches inside the cargo
compartment permit moving heavy loads. The cargo compartment can
accommodate loads ranging from 27 pallets to a mix of 17 pallets and 75
passengers. The aircraft's length is almost 182 feet. It has a height of
approximately 58 feet and a wing span of about 165 feet.
Appendix II Air Mobility Command Aircraft Used for Strategic Airlift
KC-135 Aircraft
Figure 7: KC-135 Aircraft
Source: DOD.
The KC-135's principal mission is air refueling. However, a cargo deck
above the refueling system can transport a mixed load of passengers and
cargo. The KC-135 can carry up to 41.5 short tons of cargo or 37
passengers. The aircraft length is about 136 feet, its height is
approximately 42 feet, and it has a wing span of nearly 131 feet.
Appendix III
Operational Factors That Can Affect Aircraft Capacity Utilized
The extent to which an aircraft's capacity is utilized on any mission
depends on the interrelationship of a number of operational factors,
including (1) operating constraints, such as the flight distance and
aircraft availability; (2) environmental factors, such as airfield
altitude and temperature; and (3) DOD policies, including regulations for
use of strategic airlift and initiatives to improve the supply
distribution process. This appendix describes some of these factors.
Operational Constraints There are several operational factors that can
affect the capacity utilized, including (1) aircraft availability, (2)
aircraft characteristics, (3) cargo characteristics and loading
configuration, and (4) route and fuel needs, among other factors.
According to AMC officials, these factors, among others, contribute to
capacity limitations.
Aircraft Availability Because airlift aircraft are normally in high demand
and usually highly tasked, they are reserved for movement of forces and
cargo critical to the successful execution of campaign plans. However,
competing demands can limit the availability of aircraft to meet specific
mission needs, forcing AMC planners to potentially use larger aircraft,
such as the C-5, to transport payloads that cannot maximize the available
space. Operational tempo and the number of aircraft undergoing maintenance
and assigned for training needs and crew certification drive the total
number of aircraft available to AMC officials at any given time. User
requirements and threat situations may allow little or no flexibility in
the delivery times, locations, and load configurations. Although exact
numbers fluctuate daily, AMC generally has about 85 C-5 and C-17 aircraft
available daily for strategic airlift missions. However, special events
and maintenance problems can reduce the number and type of aircraft
available for these missions. Officials told us that at the beginning of
OEF, 17 C-5 aircraft were broken and grounded at Guam for maintenance.
Efforts to improve the readiness rate of C-5 aircraft from 65 percent
reduce the availability of these aircraft further and increase the need
for C-17s. According to an AMC official, three C-17s are needed to replace
each C-5. Because C-17 aircraft are also being used for intratheater
airlift in Iraq, United States Central Command officials expressed concern
about having enough C-17s to meet strategic airlift demands.
Aircraft Characteristics Aircraft characteristics, such as the size and
shape of the aircraft's cargo compartment and strength of the aircraft
floors and ramps, operational tempo, and chronological age, can impact an
aircraft's capacity and the payload that can be transported. Aircraft have
weight, height, and width
Appendix III
Operational Factors That Can Affect Aircraft
Capacity Utilized
restrictions that can limit the amount or type of cargo that can be
transported. For example, the maximum weight limit on a C-5 ramp is 7.5
short tons, and some locations within the aircraft require a 14-inch
safety aisle to allow aircrew members clearance while securing cargo. Our
review of mission planning files showed that sometimes cargo was not
placed on the aircraft ramps because of weight constraints, thereby
leaving some available space unused. Moreover, aircraft differ on what
they can carry. For instance, the C-5 and C-17 can carry all cargo types
as well as troops, while the C-141 can carry troops, cargo loaded on a
standard-sized pallet (bulk), and oversized cargo-nonpalletized cargo that
is larger than bulk, such as vehicles. In addition, an aircraft's contours
can limit the height of pallets and rolling cargo placed in certain areas.
For example, the KC-10 has a rounded cargo compartment that requires
pallets be built to accommodate this shape; as a result, the pallets may
have less cargo on them than they could theoretically transport.
The high operational tempo, number of flying hours, and the chronological
age of aircraft can limit the payload that an aircraft can carry because
these factors contribute to structural fatigue, corrosion, cracking, wear
and tear on systems, and aircraft obsolescence. For example, United States
Central Command officials told us that C-17 aircraft are being used
extensively for both intratheater and strategic airlift for OIF, causing
the aircraft to wear out and reach their retirement dates sooner than
expected. As a result, these aircraft cannot carry payloads as heavy as
would be expected.
Cargo Characteristics and Cargo dimensions, characteristics, and placement
in an aircraft can impact
Loading Configuration
capacity utilized. AMC categorizes cargo as (1) bulk-liquid or dry cargo
that can be loaded on a standard-sized pallet without exceeding the
pallet's dimensions; (2) oversized- nonpalletized rolling stock that is
larger than bulk that exceeds the dimensions of a standard-sized pallet,
but can be transported on a C-5, C-17, C-141, C-130, or KC-10; and (3)
outsized-cargo that exceeds dimensions of oversized cargo and requires the
use of a C-5 or C-17 aircraft. When scheduling airlift, AMC attempts to
match cargo dimensions with the appropriate type of aircraft; however, a
specific type of aircraft may not be available. Cargo characteristics can
also affect aircraft capacity utilized. For example, ammunition is dense
cargo that can be loaded with little wasted space, but helicopters are
large, light, and irregularly shaped, and thus use cargo space less
efficiently, as shown in figure 8.
Appendix III
Operational Factors That Can Affect Aircraft
Capacity Utilized
Figure 8: Unloading of a HH-60G Pave Hawk Helicopter from a C-17 in
Support of OIF
Source: DOD.
Note: A single Pave Hawk helicopter takes up most of a C-17's cargo
compartment and uses multiple pallet positions. Thus, the helicopter's
dimensions do not permit loading the C-17 to its maximum allowable cabin
load.
Further, if hazardous material is transported, other types of cargo and
passengers may not be loaded on the aircraft. If enough hazardous material
is not available at the aerial port, payloads may be lighter. Each
aircraft also has a specific number of positions-referred to as pallet
positions- where cargo or passengers can be placed. For example, the C-5
aircraft has 36 pallet positions, and the C-17 has 18. Aerial
ports-airfields that have been designated for the sustained air movement
of personnel and cargo as well as authorized ports for entrance into or
departure from the country where located-track the placement of cargo and
passengers on the aircraft and the number of pallet positions used for
each mission. The dimensions and type of cargo can require the use of more
than one position, decreasing the amount of cargo or number of passengers
that can be transported. Although all pallet positions on an aircraft may
be used, the pallets may still have space for additional cargo to be
placed on them. As a result, all pallet positions may appear to be used,
but the pallets may not have met weight or volume limits. Cargo dimensions
may also require the
Appendix III
Operational Factors That Can Affect Aircraft
Capacity Utilized
use of multiple partial pallet positions. In addition, all airlifted cargo
must be secured in place using rollers and tie-downs, as shown in figure
9.
Figure 9: Loadmasters Chain Down Cargo on a C-17
Source: DOD.
Some cargo must be transported in containers or with two or more pallets
linked together. To secure these items, additional space on the aircraft
may be needed, thus limiting the placement of additional cargo on board.
Also, large equipment, such as helicopters, can take up a lot of space and
result in lighter payloads. For example, in figure 10 (an actual load plan
used during OEF), the total payload for cargo and passengers was
approximately 30 short tons. Of this, the two helicopters took up about
half of the C-17's cargo hold and accounted for about 19 short tons of the
C-17's payload. Also, one helicopter's tail hangs over the ramp,
preventing the use of this area. According to this load plan, it appears
that the space available on the aircraft was efficiently used assuming
that there was no additional cargo available to be loaded that would meet
the ramp's weight limitations.
Appendix III
Operational Factors That Can Affect Aircraft
Capacity Utilized
Source: AMC.
Figure 11 (an actual load plan used during OEF) shows how the presence of
passengers can impact aircraft capacity utilized. When passengers are
present, cargo must be placed down the center of the aircraft to provide
an aisle for passengers. For this load plan, the total payload was
approximately 23 short tons.
Source: AMC.
Fuel Considerations Aircraft range and payloads are greatly affected by a
mission's fuel requirements. As the distance increases, the fuel
requirements increase and
Appendix III
Operational Factors That Can Affect Aircraft
Capacity Utilized
the allowable payload decreases. For instance, if an aircraft must divert
around a country because it does not have permission to fly over that
nation's airspace or it must fly at higher altitudes due to security
concerns, the aircraft may need to carry more fuel and less cargo and
passengers. We have reported that an aircraft's range is significantly
reduced with only minimal additional weight or due to security concerns.
For example, for Stryker brigades every additional 1,000 tons of weight to
be airlifted reduces aircraft range by 250 nautical miles and adds 15
aircraft loads. 1 We have also reported that a C-130 aircraft's range may
be reduced if operational conditions such as high-speed takeoffs and
threat-based route deviations exist because more fuel would be consumed
under these conditions. Even under ideal flight conditions, such as
daytime, low headwind, moderate air temperature, and low elevation, adding
just a ton onboard the aircraft for associated cargo such as mission
equipment, personnel, or ammunition reduces the C-130 aircraft's
takeoff-to-landing range to 500 miles. Sometimes, the amount of cargo and
distances involved in strategic airlift operations make air refueling
necessary. AMC officials told us that air refueling is routinely done for
aircraft flying to Iraq; Afghanistan; and Ramstein Air Base, Germany. Air
refueling may reduce the aircraft's initial fuel requirement, allow for
heavier cargo loads, increase aircraft range, and reduce the need for
ground refueling. If refueling is not possible at the off-load station,
such as in Khandahar, Afghanistan, potential payloads could be reduced or
additional enroute stops could be required.
Environmental Factors Environmental factors, such as altitude, pressure,
weather, and temperature, can also affect the capacity utilized on an
aircraft by forcing planners and operators to adjust mission payloads and
timing to ensure effective, efficient, and safe mission accomplishment.
High altitudes could prevent the use of certain types of aircraft or
require lighter payloads and less fuel so that the aircraft can take off.
For example, the Sierra Army Depot in Amadee, California, is located at a
high altitude, and it is difficult for C-5s to get the lift they need to
take off if carrying more than 30 short tons; this payload is about 42
short tons less than the payload planning
1GAO, Military Transformation: Realistic Deployment Timelines Needed for
Army Stryker Brigades, GAO-03-801 (Washington, D.C.: June 30, 2003), and
Military Transformation: Fielding of Army's Stryker Vehicles Is Well Under
Way, but Expectations for Their Transportability by C-130 Aircraft Need to
Be Clarified, GAO-04-925 (Washington, D.C.: Aug. 12, 2004).
Appendix III
Operational Factors That Can Affect Aircraft
Capacity Utilized
factor. As a result, AMC officials try not to use C-5 aircraft at this and
similar locations unless C-17 aircraft are not available. AMC also needs
to consider temperature changes during the winter and summer months. For
instance, the allowable cabin load for aircraft flying into Rota Naval
Base, Spain during the summer decreases by about 10 to18 short tons
because the temperature is too high for aircraft to maintain enough lift.
DOD Policies Some DOD transportation-related policies, such as the pure
pallet initiative and the primacy of commanders' decisions, may result in
lighter payloads. DOD officials told us that the lighter payloads are
acceptable in some instances because initiatives reduce risk and customer
wait time in theater and AMC must meet commanders' time frames for
delivery of cargo and passengers.
Pure Pallet Initiative While DOD's pure pallet initiative delivers
palletized cargo to customers in the theater more quickly, it can result
in lighter pallets and payloads. Initiated in March 2004 at Dover Air
Force Base, Delaware; Charleston Air Force Base, South Carolina; and
Ramstein Air Base, Germany, DOD's pure pallet initiative is intended to
simplify and speed up airlift shipments into the United States Central
Command's area of responsibility by building and shipping individual
aircraft pallets with cargo for a single customer. The pure pallet
initiative decreases the time needed on the receiving end to distribute
palletized cargo to individual customers by transferring the sorting of
cargo to the originating aerial port. Normally, a customer's cargo is
loaded onto an aircraft pallet with cargo for other customers within the
same region. Under this system, a single pallet could contain cargo for
dozens of customers. The pallet would be broken down when it arrived at
the destination aerial port, sorted, repalletized, and distributed to
individual customers. When a pure pallet arrives at the deployed aerial
port, it can be pulled from the aircraft and immediately handed off to the
customer or placed on a truck or another aircraft for transport to remote
locations. In addition, the initiative recognizes that in Iraq and
Afghanistan, aerial ports are restricted as to the amount of cargo
processing facilities, amount of equipment, and number of people because
of the threat of attack. However, DOD officials acknowledge that having
enough cargo to fill an entire pallet is problematic. To maximize pallet
and aircraft utilization, the aerial ports can hold cargo for up to 5 days
for the Army and up to 3 days for the Marine Corps. However, cargo is
palletized when it reaches 120 hours of port hold time or enough cargo is
available to fill a pallet causing it to either cube out or weigh out. As
we reported in April
Appendix III
Operational Factors That Can Affect Aircraft
Capacity Utilized
2005,2 the result is potentially longer processing times at the
originating aerial ports in order to reduce customer wait time in theater.
AMC tracks pure pallet weights each week, aiming for an average of 1.4
short tons per pallet. AMC data show that all three aerial ports generally
met or surpassed the average pure pallet weight goals.
Combatant Commander According to AMC officials, the most efficient way to
move passengers and
Decisions cargo is not always the most appropriate during contingency
operations. During OEF and OIF, combatant commanders frequently required
AMC to transport troops with their equipment on the same aircraft.
According to AMC officials, it would have been more efficient to move the
troops on one aircraft and transport their equipment on a second aircraft
immediately following the first. However, commanders fear that passengers
would arrive at their destinations and equipment sent on the second
aircraft would be delayed due to maintenance problems or, if sent on a
military aircraft, the mission might be canceled. As a result, AMC may fly
aircraft with reduced payloads in order to meet combatant commanders'
delivery time frames. However, these decisions take into account the
expected situation at the destination; some units, such as special
operations forces and the Marines, immediately require their equipment, so
separating passengers and equipment is not the preferred transportation
method. Although the aircraft may be underutilized, AMC is meeting its
primary objective to deliver "the right items to the right place at the
right time."
2GAO, Defense Logistics: Actions Needed to Improve the Availability of
Critical Items during Current and Future Operations, GAO-05-275
(Washington, D.C.: Apr. 8, 2005).
Appendix IV
Comments from the Department of Defense
Appendix IV
Comments from the Department of Defense
Appendix V
GAO Contact and Staff Acknowledgments
GAO Contact William M. Solis (202) 512-5140
Acknowledgments In addition to the contact name above, Ann Borseth,
Assistant Director; Krislin M. Bolling; Virginia A. Chanley; Karen N.
Harms; Linda S. Keefer; Ronald La Due Lake; Renee McElveen; Maria-Alaina
I. Rambus; Vanessa R. Taylor; and Robert K. Wild also made key
contributions to this report.
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