Bird strikes on angle-of-attack sensors are relatively common.
A Times review of two F.A.A. databases found hundreds of reports of bent, cracked, sheared-off, poorly installed or otherwise malfunctioning angle-of-attack sensors on commercial aircraft over three decades.
Since 1990, one database has recorded 1,172 instances when birds — meadowlarks, geese, sandpipers, pelicans and turkey vultures, among others — damaged sensors of various kinds, with 122 strikes on angle-of-attack vanes. The other database showed 85 problems with angle-of-attack sensors on Boeing aircraft, including 38 on 737s since 1995.
And the public databases don’t necessarily capture the extent of incidents involving angle-of-attack sensors, since the F.A.A. has additional information. “I feel confidence in saying that there’s a lot more that were struck,” said Richard Dolbeer, a wildlife specialist who has spent over 20 years studying the issue at the United States Department of Agriculture, which tracks the issue for the F.A.A.
A Simple Request
On March 30, 2016, Mark Forkner, the Max’s chief technical pilot, sent an email to senior F.A.A. officials with a seemingly innocuous request: Would it be O.K. to remove MCAS from the pilot’s manual?
The officials, who helped determine pilot training needs, had been briefed on the original version of MCAS months earlier. Mr. Forkner and Boeing never mentioned to them that MCAS was in the midst of an overhaul, according to the three F.A.A. officials.
Under the impression that the system was relatively benign and rarely used, the F.A.A. eventually approved Mr. Forkner’s request, the three officials said.