Boeing Co. withheld information about potential hazards associated with a new flight-control feature suspected of playing a role in last month’s fatal Lion Air jet crash, according to safety experts involved in the investigation, as well as midlevel FAA officials and airline pilots.
The automated stall-prevention system on Boeing 737 MAX 8 and MAX 9 models — intended to help cockpit crews avoid mistakenly raising a plane’s nose dangerously high — under unusual conditions can push it down unexpectedly and so strongly that flight crews can’t pull it back up. Such a scenario, BoeingBA, -0.98% told airlines in a worldwide safety bulletin roughly a week after the accident, can result in a steep dive or crash — even if pilots are manually flying the jetliner and don’t expect flight-control computers to kick in.
That warning came as a surprise to many pilots who fly the latest models for U.S carriers. Safety experts involved in and tracking the investigation said that at U.S. carriers, neither airline managers nor pilots had been told such a system had been added to the latest 737 variant — and therefore aviators typically weren’t prepared to cope with the possible risks.
“It’s pretty asinine for them to put a system on an airplane and not tell the pilots who are operating the airplane, especially when it deals with flight controls,” said Capt. Mike Michaelis, chairman of the safety committee for the Allied Pilots Association, which represents about 15,000 American Airlines pilots. “Why weren’t they trained on it?”