Boeing, FAA to Issue Safety Alerts Following Lion Air Crash


Responding to the Lion Air jetliner crash that killed 189 people in Indonesia last week, manufacturer

Boeing
Co.


BA 1.24%

and U.S. aviation regulators intend to issue twin safety warnings about potentially suspect flight-control software that can confuse pilots and lead to a steep descent of the affected aircraft model, according to people familiar with the matter.

The moves are the first public indication that investigators suspect a possible software glitch or misinterpretation by pilots—related to an essential system that measures how high or low a plane’s nose is pointed—may have played an important part in the sequence of events that caused the Boeing 737 Max 8 to plunge into the Java Sea.

Incorrect data about the angle of the plane can lead to a cascade of cautions and warning that can be misinterpreted by pilots when they are flying manually, even as safety systems automatically adjust flight-control surfaces to push the nose of the plane downward, these people said.

The anticipated actions by Boeing and the U.S. Federal Aviation Administration are preliminary, these people said, and are expected to stop short of urging or mandating replacement or inspection of any specific onboard system. Rather, they amount to an official red flag for pilots, highlighting potential hazards stemming from the interaction of certain software with various other cockpit alerts, and reiterating the importance of following standard procedures under such circumstances.

In the wake of previous crashes in which pilot error or confusion were contributing factors, manufacturers and the FAA have issued safety warnings reiterating the limits of certain aircraft systems and the importance of pilots’ following recommended procedures.

In this case, according to one of the people familiar with the matter, the aim is similarly to emphasize the importance of following standard flight-deck procedures so pilots avoid misunderstanding or improperly reacting to certain cockpit displays or alerts when manually flying the aircraft.

The crew of Lion Air Flight 610 reverted to manual flight after experiencing unreliable airspeed indications shortly after takeoff from Jakarta in good weather, according to preliminary information gathered by the investigation. Minutes after the crew communicated the situation to air-traffic controllers and gradually gained altitude as part of an apparent effort to troubleshoot the problem, the twin-engine plane plunged into the water at high speed.

While singling out potentially problematic software associated with what is called the angle-of-attack indicator system, the warnings don’t explicitly link that system to the cause of the Oct. 29 accident. Other factors may have contributed, according to safety experts tracking the investigation.

Airline and FAA safety experts haven’t identified a previous pattern of similar software issues in the fleet, according to safety experts familiar with the details. But preliminary data from the accident suggests the angle-of-attack system may have malfunctioned for some reason, potentially confusing the crew about the plane’s speed and attitude, according to one person briefed on the issue. Investigators haven’t publicly described such a scenario.

As early as Tuesday evening, according to the people familiar with the matter, the Chicago-based plane maker was expected to issue an operations bulletin to all airlines flying 737 Max 8 variants. The document refers to software associated with the angle-of-attack system, they said.

Within hours, FAA officials are poised to issue a complementary follow-up safety document raising basically the same issues, these people said. The emergency airworthiness directive will be binding on all U.S. carriers flying Boeing 737 Max 8 versions and is expected to be embraced by regulators world-wide.

Just a day earlier, industry and government officials weren’t expecting such rapid action. But clues downloaded recently from the plane’s flight-data recorder apparently were worrisome enough to prompt Boeing and the FAA to move quickly in drafting and coordinating the pair of safety warnings.

More broadly, investigators are trying to understand why the last four flights of the crashed Lion Air jet all experienced problems with the new Boeing’s airspeed indicator, and how interaction between such faulty readings and software associated with the other system could have led to the accident.

Write to Andy Pasztor at andy.pasztor@wsj.com



Source link

Leave a Reply

Your email address will not be published. Required fields are marked *