Defense Transportation: Air Mobility Command Needs to Collect and Analyze Better Data to Assess Aircraft Utilization
Published: 2005-09-29T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: 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.
section_title: What GAO Found
paragraphs: 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. 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.

section_title: Letter
paragraphs: 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).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. 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  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. 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  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.
subsections: section_title: Background
paragraphs: 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.  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. Strategic airlift moves cargo and  passengers between the continental United States and overseas theaters or  between overseas theaters. AMC operates military aircraft that constitute  the U.S. strategic airlift fleet, including the C-5, C-17, and C-141 aircraft  (app. II describes each aircraft). 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.
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  (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.
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.
section_title: The Extent to Which AMC Used Capacity as Efficiently as Possible on Strategic Military Aircraft Cannot Be Readily Ascertained
paragraphs: 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.
subsections: section_title: Historical Mission Planning Files Have Limitations That Prevent Their Use to Determine Whether AMC Used Aircraft Capacity as Efficiently as Possible
paragraphs: 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.
section_title: One AMC Database Is Also Not Useful for Assessing Whether Aircraft Capacity Was Used as Efficiently as Possible
paragraphs: 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.
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. 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.
section_title: Analysis of AMC Data Showed That a Significant Number of Strategic Airlift Missions Flew with Payloads Lighter Than Established Planning Factors
paragraphs: 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.
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.
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.
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.
section_title: Conclusions
paragraphs: 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.  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.
section_title: Recommendations for Executive Action
paragraphs: 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:  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.
Systematically collect and analyze information on operational factors  that impact payloads transported on strategic airlift missions to identify  ways that DOD may be able to use an aircraft’s capacity as efficiently as  possible.
section_title: Agency Comments and Our Evaluation
paragraphs: 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. § 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 solisw@gao.gov. 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.
section_title: Scope and Methodology
paragraphs: 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:  13th Corps Support Command, Fort Hood, Killeen, Texas.   3rd Army Corps, Directorate of Logistics, Fort Hood, Killeen, Texas.   437th Aerial Port Squadron, Charleston Air Force Base, South Carolina.  4th Infantry Division, Fort Hood, Killeen, Texas.   819th Rapid Engineer Deployable Heavy Operational Repair Squadron  Engineer, Malmstrom Air Force Base, Montana.
Air Mobility Command (AMC), Scott Air Force Base, Illinois.
I Marine Expeditionary Force, Camp Pendleton, California.
II Marine Expeditionary Force, Camp Lejeune, North Carolina.
Joint Chiefs of Staff, Joint Staff Logistics Directorate, Arlington,  Virginia.
Office of the Secretary of Defense, Program Analysis and Evaluation,  Arlington, Virginia.
United States Central Command, MacDill Air Force Base, Tampa,  Florida.
United States Joint Forces Command, Norfolk, Virginia.
United States Army Forces Command, Fort McPherson, Georgia.
United States Army Installation Management Agency, Arlington,  Virginia.
United States Transportation Command, Scott Air Force Base, Illinois.
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 missionsoccurring 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,  (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.
section_title: Air Mobility Command Aircraft Used for Strategic Airlift
paragraphs: 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).
section_title: Operational Factors That Can Affect Aircraft Capacity Utilized
paragraphs: 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.
subsections: section_title: Operational Constraints
paragraphs: 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.
subsections: section_title: Aircraft Availability
paragraphs: 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.
section_title: Aircraft Characteristics
paragraphs: 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  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.
section_title: Cargo Characteristics and Loading Configuration
paragraphs: Cargo dimensions, characteristics, and placement in an aircraft can impact  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.
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  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.
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.
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.
Aircraft range and payloads are greatly affected by a mission’s fuel  requirements. As the distance increases, the fuel requirements increase and  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. 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.
section_title: Environmental Factors
paragraphs: 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  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.
section_title: DOD Policies
paragraphs: 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.
subsections: section_title: Pure Pallet Initiative
paragraphs: 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 2005, 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.
section_title: Combatant Commander Decisions
paragraphs: According to AMC officials, the most efficient way to move passengers and  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.”
section_title: Comments from the Department of Defense
section_title: GAO Contact and Staff Acknowledgments
subsections: section_title: GAO Contact
section_title: Acknowledgments
paragraphs: 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.