Safety feature on 737 may have caused crash
CHICAGO: The weather in Jakarta was clear on the morning of October 29 when a brandnew Boeing 737 Max passenger jet left Indonesia’s capital on a domestic hop to a nearby island. Soon after, Lion Air Flight 610 plunged into the Java Sea, killing all 189 people aboard.
No foul play is suspected. Something cataclysmic occurred on board that potentially involved pilot error or equipment malfunction.
But as safety officials, the airline and Boeing investigate, one chilling scenario has emerged: this supermodern, highly automated aircraft may have crashed itself by suddenly diving into the water. The pilots apparently had no time to recover.
The 737 is the workhorse singleaisle jet of Chicagobased Boeing. The 737 Max is the newest, most advanced version; Lion Air’s 737 Max 8 plane went into service just a few months ago.
What may have happened? One theory is that this aeroplane may have outsmarted its pilots. The computerised cockpit controls of the 737 Max have a new safety feature designed to protect the plane from a midflight stall. If sensors detect the aircraft rising too steeply, the controls will react automatically by pushing the nose down.
That’s all good if sensors are delivering accurate flight data, but what if those readings were faulty or misinterpreted? In that case, the plane could sense danger where there was none and overreact by hurtling downward.
Lion Air reported data problems with the doomed plane.
On the previous flight, the crew noticed a bad reading related to the aircraft’s flight angle. So the pilot ‘‘improvised’’ by turning off a tail mechanism that could have sent the plane into a dive, an Indonesian safety official told The New York Times. That slick move was not in the flying manual, the official said.
Boeing markets the 737 Max as being similar to the previous generation, which means training pilots is relatively easy and inexpensive. According to The Wall Street Journal, Boeing did not highlight the risk of a sudden plummet because designers could not picture a scenario in which bad data, pilot response and nose overcorrection would conspire to risk a crash. Pilots criticised Boeing’s handling of the issue.
‘‘It’s pretty asinine for them to put a system on an airplane and not tell the pilots . . . especially when it deals with flight controls,’’ Captain Mike Michaelis, chairman of the safety committee of the Allied Pilots Association at American Airlines, told the The Wall Street Journal. — TCA