Accident Details
On 19 May 2016, at 0832 hours local time, a B-52H strategic bomber, tail number 60-0047, assigned to the 69th Expeditionary Bomb Squadron, 5th Bomb Wing, Andersen Air Force Base, Guam, departed the prepared-surface overrun of Runway 06 Left during a high-speed, heavy-weight, aborted takeoff. The mishap crew consisted of the Mishap Pilot, Mishap Co-Pilot, Mishap Radar Navigator, Mishap Navigator, Mishap Electronic Warfare Officer, an augment pilot occupying the Mishap Gunner station, and an Instructor Weapon System Officer occupying the Mishap Instructor Pilot jump seat. They were conducting a Higher Headquarters Directed mission. All crew members were treated for minor injuries consistent with a ground egress. The aircraft sustained total damage with a loss valued at $112 million. No private property was damaged.
Sequence of Events
The crew was cleared for takeoff at 0831L. The aircraft accelerated within performance standards verified by takeoff and landing data for S1 timing and S1 decision speed. Approximately three to five seconds after reaching the S1 speed of 111 knots, the Mishap Pilot, Mishap Co-Pilot, and Mishap Navigator observed birds in front of the aircraft at wing level. Shortly thereafter, the Mishap Pilot and Mishap Co-Pilot observed engine indications for engines 5, 6, and 7 quickly spooling back from the required takeoff setting. The Mishap Pilot also observed high oil pressure indications on engine 8 and a noticeable left-to-right yawing motion.
Accelerating through approximately 142 knots, the Mishap Pilot simultaneously announced and initiated aborted takeoff emergency procedures. The throttles were set to idle thrust, airbrakes set to six, and the Mishap Pilot began continuous braking pressure. The Mishap Co-Pilot deployed the drag chute at 135 knots; the chute failed to inflate properly. At 2,500 feet of runway remaining, the Mishap Pilot shut off the outboard engines (numbers 1/2 and 7/8). Shortly thereafter, the Mishap Pilot announced that the aircraft and crew would depart the prepared surface. The Mishap Electronic Warfare Officer jettisoned the defensive compartment starboard-side hatch, and the Mishap Pilot shut off the inboard engines (numbers 3/4 and 5/6). The aircraft departed the prepared surface, shearing the main landing gear. It came to rest slightly canted from runway centerline, right wing down, approximately 300 feet from the runway, and subsequently caught fire. The crew performed emergency aircraft shutdown procedures and safely egressed through the Mishap Electronic Warfare Officer's hatch.
Probable Cause
The Accident Investigation Board President found by a preponderance of the evidence the cause of the mishap was the Mishap Pilot analyzed visual bird activity and perceived cockpit indications as a loss of symmetric engine thrust required to safely attain flight and subsequently applied abort procedures after S1 timing. The Board also identified factors substantially contributing to the mishap: drag chute failure on deployment and exceeding brake-energy limits resulting in brake failure.