Pilot: What occurred to that Lion Air flight? (Opinion)


As with most airplane accidents, the tragedy of Lion Air Flight 610 might have been prevented. The airplane crashed shortly after takeoff from Jakarta on November 6, plunging into the Java Sea and killing all 189 individuals on board.

First, this accident remains to be within the discipline investigation course of; till the outcomes of that probe are in, it is necessary to keep away from hypothesis. However individuals who journey by air understandably wish to know: is it secure to get on a Boeing 737 MAX airplane? The 737 MAX, the doomed mannequin on this crash, and the preferred airplane in Boeing historical past, is flown by (or on order for) near 40 airways, according to the Washington Post.

Let’s take a look at what we all know up to now. The Digital Flight Knowledge Recorder (DFDR) that was recovered and analyzed signifies some very disturbing circumstances right here — ones that ought to infuriate pilots who fly these planes.

The 737 MAX is an airframe design that dates again to 1967. It’s the newest in Boeing’s line-up, features a “fly-by-wire” (that’s, laptop managed) digital flight management system and extremely environment friendly turbofan engines. As a result of the engines are additionally extra highly effective and heavier than earlier variations of the airplane, the tendency for an “underslung” (beneath the wing) mounted engine to trigger the nostril of the airplane to rise when thrust is elevated, particularly at decrease airspeeds, turns into extra pronounced.

Boeing compensated for the nose-up tendency by programming the flight management computer systems to use nose-down stabilizer trim routinely, a perform that’s invisible to the pilot even when hand-flying the airplane.

This extra Maneuvering Traits Augmentation System (MCAS) was added to supply safety towards an aerodynamic stall, which principally happens at decrease airspeed, by programming the pc to cease pilots from elevating the nostril: briefly, it fights pilot enter to forestall the airplane from stalling.

The set off for the MCAS system is the angle of assault (AOA) detector, which measures the angle between the wings and the air move. If the AOA detects an approaching stall, the MCAS is activated. In Lion Air’s scenario, it seems that the AOA was defective, transmitting inaccurate knowledge. The pilots unsuccessfully struggled to wrestle management of the airplane away from the pc.

Having spent my total airline profession on Boeing airplanes, I’ve at all times preferred their philosophy of designing the electronics to work in concord with the pilot moderately than defending the airplane from the pilot. The MCAS system appears to symbolize the latter.

However right here is why 737 pilots (and everybody else) must be indignant: The MCAS system was apparently not particularly described within the airplane operation guide. (Boeing Chief Govt Dennis Muilenburg informed Fox Enterprise Community on Tuesday that the knowledge was obtainable as a part of the guide. CNN has asked Boeing for a duplicate of the unique manuals issued to carriers who purchased the Boeing 737 MAX 8, however Boeing has not offered these operation manuals to CNN.) In response to skilled pilots, the system was by no means included in earlier variations of the airplane.

How can pilots compensate for a malfunction if they don’t seem to be conscious of the way it works? And recognition is essential. If crews do not perceive the abnormality, they can not react by way of an applicable emergency guidelines. For Lion Air, their altitude of 5,000 ft did not depart a lot time to investigate the scenario after which react.

Boeing is now reportedly taking the unprecedented step of not solely briefing prospects — that’s, airways utilizing the 737 MAX — but in addition involving the pilots’ unions. And as of November 9, a process that includes pilots disconnecting the stabilizer trim switches within the cockpit is now included in flight manuals as an answer to Engine Indicating and Crew Alerting System (EICAS) warning messages that relate to defective sensors. I labored as an airline pilot for 34 years, and this very fast response is, in my expertise, unprecedented.
Some reports point out that the AOA detection system might have malfunctioned on earlier flights with one other crew. Was the malfunction repaired in keeping with Boeing’s procedures? Was it the identical malfunction skilled by the accident crew? Did the airplane react the identical means on the Lion Air accident flight? Did the malfunction on the earlier flight happen at a better and safer altitude? The solutions to those questions are what the continued investigation will decide.

Is the 737 MAX a secure airplane? The brief reply is “Sure.” Now that pilots are armed with higher information of the MCAS system and have a fast answer for associated abnormalities, the airplane is even safer.

However Boeing nonetheless has lots of explaining to do.

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