Bird strike - Loss of four engines - B-52 - AVweb

B-52 Probably Ingested Birds In Four Engines

By Geoff Rapoport

The Air Force crew of MACHO 11 can now top Sully’s two-engine bird ingestion. The Air Force B-52 that crashed when departing from Andersen Air Force Base last May experienced indications consistent with failure of all four starboard engines due to bird ingestion. The Boeing B-52 Stratofortress is an eight-engine, turbojet-powered strategic bomber. The aircraft commander told investigators that he saw birds at wing level, felt or heard “thuds” and “observed engine indications for numbers 5, 6, and 7 ‘quickly spooling back’ from the required takeoff setting” with high oil pressure on engine 8. The aircraft commander then “simultaneously announced and initiated the takeoff abort and noted the airspeed approached ‘about 142 knots,’” according to the Accident Investigation Board (AIB) accident report. B-52 crews calculate V_mca for each flight based on loss of two engines on the same side, but generally make no provision for loss of all four engines on one side. The AIB calculated that the three engine-out V_mca would have been 194 KIAS, assuming the number 8 engine had maintained thrust and all other engines had been maintained at takeoff power. AIB simulations suggest that the aircraft would have been able to climb and maintain control with maximum thrust on the number 8 engine and reduced thrust on engines 1 and 2. One crew member was not in an ejection seat, making the normal objective of attaining bail-out altitude an undesirable outcome.
During the abort, the drag chute failed, which the AIB determined ultimately prevented the aircraft from stopping within the remaining paved surface. Further complicating the analysis, the Air Force Research Laboratory’s Teardown Deficiency Report was unable to find any “evidence of any organic material being processed through the engines.” Without reaching a conclusion about whether the aircraft actually lost power due to bird ingestion, the AIB 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 aircraft was destroyed, but all crew members survived the overrun and escaped prior to the post-crash fire.
Full report available below for interested readers.