First in fleet: KC-135 global air traffic management

Defense AT&L, May-June, 2004 by L.D. Alford

The advent of global air traffic management (GATM) is radically changing the world of global reach aviation. To ensure the United States military access to global air routes, all aircraft using them must reach these standards by the time the world's air traffic control systems are converted to meet the GATM requirements. The complex modifications to aircraft and operations are made more difficult by the amorphous and changing requirements of the overall GATM system. The Global Reach System Program Office put together a program to meet the GATM needs of the KC-135 tanker aircraft being flown by the Air Mobility Command. The KC-135 GATM program has the privilege of being the first Department of Defense (DoD) GATM program to deploy a full-up GATM capability.

The KC-135 Program

The success of the KC-135 GATM program can be traced directly back to the building block nature of the program and lessons learned from earlier KC-135 programs. The Air Force did not want the first GATM aircraft fleet to end up a boat anchor. Actually, the KC-135 was not originally intended to be the Air Force's first GATM program. The C-5 Aviation Modernization Program (AMP) went on contract before the KC-135, and the KC-10 and C-17 were scheduled to deliver aircraft with GATM ahead of the KC-135. The KC-135 GATM program pulled ahead and passed all of these programs because it met key Air Force needs: a program that could lead the fleet and supply a first capability to support the deployed air forces with tankers and cargo carriers, and that could pave the way for the GATM modifications in other Air Force aircraft.

Lessons learned from past KC-135 programs among others indicated the need to address three key program areas: a strong systems engineering development approach, a solid system safety engineering process, and a robust test program. The KC-135 GATM program focused on these areas to improve and capitalize on the lessons learned. The Wright-Patterson program was set up to ensure a developmental approach to the integration of mainly commercial-off-the-shelf (COTS) equipment. Both the contractor and the government strove to develop a MIL-STD-882 safety program that would guarantee the completed product would be airworthy and meet user needs without major changes. Developmental and operational testers were brought early into the program to make certain a sufficient level of test and evaluation was used to wring out the design and the final aircraft.

These steps were very successful and produced a product on time with little cost growth. The details of the organization of these three critical pieces of the KC-135 GATM program will benefit the design of any government acquisition program, especially for COTS-based or largely COTS-based acquisitions that require military agency certification.

Systems Engineering Development Approach

Major modifications to complex systems are not exclusively sustainment activities. They necessitate the involvement of developmental system experts and expert integrators. In the Air Force, the Aeronautical Systems Center is the primary developer for aviation systems. The use of this organization's deep engineering experience and tight relationship with the Air Force Research Lab was fundamental in aiding the success of the KC-135 GATM program. Additionally, the Electronic Systems Center provided support to the program in avionics and data systems. This support included a GATM performance assessment and a data chain certification of the Air Force Flight Management System (AFFMS) and the digital aeronautical flight information file (DAFIF) it uses. This focus on a data chain certification to assess the navigation database subsystem is unique in the military but reflects an obvious need to ensure the safety and airworthiness of these types of highly integrated navigation systems. This is a parallel effort with civil systems such as the Jeppeson navigation database, but it takes a step ahead under the aegis of Air Force airworthiness that is necessary for military systems. The eventual goal for the Air Force is to achieve a fully airworthy navigation database.

The integration of COTS items is a developmental effort. This focus in the program was a key factor leading to its success. Every effort was made in the KC-135 GATM program to acquire previously certified and civil-certified components. This saves money by significantly reducing the cost to test, verify, and certify individual components. This way, the focus of the program was fully on making the pieces work together and certifying the integrated system. A program that doesn't ensure this requires deep investments in engineering, test, and safety to develop and certify the components as well as the overall integration.

COTS itself can become both a cost and sustainment driver in the support of a program. No program can completely isolate itself from these certain problems, but the KC-135 GATM program did work to reduce these problems by using state-of-the-art and certified equipment.