Much more than just another 747
In mid-December 1999, aircraft number 1238, a bare bones 747-400 Freighter, rolled off the Boeing Co. assembly line in Everett, Wash. It's buyer was already determined -- the U.S. Air Force had become the owner of what would become the Airborne Laser (ABL). Slightly more than a month later, on Jan. 22, 2000, the aircraft was flown to the Boeing Modification Center in Wichita, Kan. By then it had acquired a name -- prototYpe Attack Laser model 1-A (YAL-1A) -- and a new number -- 00-0001 -- designating it the first military aircraft of the new millennium.
Within hours, workers began removing the nose of the new plane, the first step in an extensive modification program that would leave almost no section of the original aircraft untouched. The section that would house a cargo loading door and the weather radar in a commercial aircraft had to be disassembled to make room for what would become ABL's most visible distinguishing characteristic -- a bulbous, 14,000-pound rotatable turret.
Although Boeing built and modified the aircraft, Lockheed Martin in Sunnyvale, Calif., constructed the turret and the optical system. The Chemical Oxygen Iodine Laser (COIL) -- the megawatt-class laser that will be used to destroy boosting ballistic missiles ? was built by Northrop Grumman in El Segundo, Calif. Boeing also engineered the battle management system and is responsible for seeing that the subsystems are integrated into YAL-1A, which moved from Wichita to Edwards Air Force Base, Calif., in December 2002, almost three years to the day since it came off the assembly line. The program is under the management of the Missile Defense Agency (MDA).
The modification program at the Wichita facility ? which also customizes such high-end aircraft as Air Force One ? took two years to complete. Boeing officials said later that it was the largest modification of a military aircraft they had ever attempted.
Before YAL-1A made its maiden flight in its ABL incarnation on July 18, 2002, with thousands of pounds of metal balls in bags in the aft section to simulate the weight of the COIL and its support equipment, workers at Boeing had, among other things:
- Invested 1.6 million man-hours of labor on the project;
- Engineered a 4,862-pound wall, called a Station 1000 bulkhead, in the mid-section of the aircraft to keep the crew in the forward section safe from any unlikely, but possible chemical leaks that might occur in the aft laser section, plus a bulkhead in the forward section (Station 220) to support the weight of the turret;
- Replaced more than a dozen horizontal support beams in the aft section to help support the COIL's weight;
- Replaced aluminum skin on the underbelly with two 25-foot-long by 5.5-foot-wide sheets of titanium to withstand the heat of the laser's hot exhaust;
- Put in an air refueling system so YAL-1A can stay aloft longer;
- Built in six infrared sensors to detect and track boosting missiles;
- Laid enough new wiring to serve the electrical needs of more than 3,000 typical homes
Before YAL-1A was consigned to a hangar at Edwards, where its nose was once again removed so the turret could be reinstalled with the integrated optics, it completed more than a dozen test flights, plus one to the Boeing shop to be painted in its Air Force colors. The flights included a refueling mission and one as an observer in an MDA test over the Pacific during which ABL tracked the MDA target from cloud-break to engine burnout.
Airborne Laser System Program Office, Office of Public Affairs,
3300 Target Road, Building 760, Kirtland AFB, NM