This Lion Air accident is errily similar to an Airbus A320 crash in France due to a maintenance induced malfunction of the angle of attack (AoA) sensor. Like the Boeing 737, the A320 is a computer-controlled flight-by-wire flight control system. AoA sensor inputs are input for maintaining controlled flight in both aircraft types.
In the A320 accident, the AoA sensor malfunctioned sending erroneous inputs to the flight control computer. The flight control computer thinking that the AoA signals were correct was "tricked" into putting the aircraft into a steep dive from a low altitude which the aircrew did not have time (or understanding) to recover.
It would seem that this Lion Air aircraft had some type of malfunction in AoA sensor operation which triggered this (new) stall recovery software feature in the 737Max flight control computer sending the aircraft into a steep dive from a low altitude.
Had the Lion Air aircrew realized what was happening as soon as the "dive" started, and knew how to respond to override the stall prevention system in flight control system computer, they might have saved the aircraft, However, all this started at low altitude, like the A320 accident, and the aircrew had little time to trouble shoot the malfunction. They either had to act instantly or they were doomed.
3
It is inconceivable to me that an aircraft that has been in development for over five years has systems that the APA just found out about. Doesn't Boeing consult with pilots outside the company when they develop new systems, and aren't those systems - being new - part of the simulator training? This strikes me as very odd.
But no one factor results in an accident. In this case the airplane should have been pulled from service with its history of safety defects, especially considering Lion Air's corporate history of safety lapses. This accident was tragically avoidable.
2
I was working in the Douglas flight test department in Long Beach California, on the 83 series DC6, the stretched model.
We were testing zero zero automatic landing systems. However the electronics were not as accurate as they are today, the planes did not use GPS navigation, but relied on the omnirange and glidslope signals. We were limited to 200' before going to manual landing. We had installed a cutoff switch that immediately disabled the auto flight controls.
But the other requirements was all the pilots had to be able to fly the plane manually. In those days when you took pilot training in light aircraft, you learned to put the plan into a stall, and also a spin. One of the first things that was drilled into you was needle, ball, airspeed. We have see several examples of inflight errors where all the instrument training seems to have been given in a simulator.
There is no substitute for hands on experience in real time, in real air.
11
@David Underwood. We're getting very close to the man and the dog.
Here we go. Welcome to "Airliner Crash, 2018 version.". Step #1 - initiate the public relations war. Whatever the fault, it certainly wasn't me. Step #2 - recover the flight data recorder. Maybe.
Who knows where it is going to end, but one thing is clear from this article - the Pilots' Union is taking sides.
Hopefully, some day we will actually find out what really happened, and whether the autopilot can truly render the plane unflyable. At this point, I consider that to be possible, but very unlikely.
Much more likely, IMO, is that a manageable failure occurred, and that the pilots did not handle it properly. Personally, I view what is in the 8Max checklist to be irrelevant. If the autopilot starts doing something stupid, you disconnect it and fly the aircraft. (Attention all car drivers: the same can be said for you and your auto cruise control.)
NYT needs to be careful to avoid being manipulated in this public relations war. I suggest retaining a qualified pilot with the applicable ratings to review your articles before publication.
2
Its way too early to blame Boeing, pilot or anybody since investigation is still in going.
The crash of AirFrance in the Atlantic off Brazil is a case in point.
For two years, the aviation world wondered if all Airbus 330 with a joystick maneuvering system should be grounded because it was inherently unsafe to fly manually with that joystick.
Until, Scripps retrieved the black boxes from a couple of miles deep in the ocean.
Analysis of black boxes made it clear that the crew on the flight deck misread speeds being fed from a pitot tube. They kept on disengaging auto systems - to their own detriment - all the time while plane was fast losing altitude - this from a cruise altitude of some 33,000 and ended up crashing belly down - so to speak.
The impact was so violent as to crush pantry carts into pancakes.
There was nothing wrong with design of aircraft - as it was concluded.
Ditto here.
It is clear though that the airline should have grounded the aircraft - if for nothing else - to investigate these repeated anomalies.
Now, there is a comment below about stalling.
I am a Caltech graduate in aerospace engineering and worked towards my flight license.
A stall can occur at any speed as long as the angle of attack is sufficiently high to lose "lift" which should always be at least as great as airplane weight and perhaps slightly higher to ensure no loss of altitude.
Fighter planes can defy angle of attack because of it's high energy.
1
The NYT needs to stop publishing uneducated speculation. As far as the pilot's unions are concerned they will never admit a crash was caused by pilot error. One prime example is their refusal to admit the KLM pilot that caused the crash of two B747 aircraft in the Canary Islands was to blame when it has been proven it was his fault.
1
This problem will be "fixed" because there are billions of dollars riding on it. There's no way the fleet of 737 Max's will be grounded, even if a few people have to die now and then. Watch how quickly Boeing and its captive "regulator," the FAA, will pronounce this problem "fully addressed and completely resolved."
1
A small pedantic point:
A stall is not necessarily related to the position of the nose of the aircraft, but is related to the critical angle of attack of the wing, where the wing meets the airflow. This can change entirely independent of the pitch of the aircrafts nose due to severe airflow changes.
However, they often correlate so closely that the usual correction is to increase speed and pitch the nose up. Its a small point, but I rarely get to use what I learned in flight school in the NYT comment section.
6
@Mark F, I suspect that you meant to write that to recover from a stall "the usual correction is to increase speed and pitch the nose DOWN."
7
@Mark F. Further pedantic point: Stalls can occur at any speed. Their a function of lift, not speed. In your flight training you practiced what is called a take off and departure stall where the angle of attack is too high even though you're using full power for initial climb out. So the first thing you do is nose down then power if you need it, but *after* recovery from the stall.
1
I fly a different Boeing Jet, but to me regardless of why this aircraft had a runaway stab trim, the emergency procedure is still the same. Apply control force against the stab runaway, trim against the runaway trim situation and activate the trim cutout switches. The fact it was caused by a new system or a system with a different acronym does not change the procedure for dealing with a runaway stab trim situation in the 737, the 767 I fly, or just about any aircaft in existence with a Stabilator trim system. To me this crew did not handle the emergency situation properly. We can attempt to blame Boeing and cost them money, but either the pilots did not know what they were doing or they were not trained well enough to handle the emergency. From everything I know as a pilot and have read about this accident, it should never have happened.
7
@Jeff Izo
That's fine if you know the stabilizer trim is being repeatedly moved nose down, but the only indications the pilots had to deal with said 'air speed disagree' and 'altitude disagree'. At first, at least, they probably thought they had pitot and static disagreement, and would have had no reason to think the trim system was running away. When they noticed the trim wheels moving they would have been startled and possibly baffled for the short time they had to figure out what to do.
3
Your answer concerns me, as you seem to imply that pilots are incapable of flying an airplane based on their own sensory perceptions. I’m not a pilot, but I’m sure a Cessna pilot has the knowledge to react to an instant nose-down without the assistance of a raft of computers. It reminds me of the complete disorientation of the pilots of Air France 447 which flew into the sea after a simple air speed indicator froze. Are pilots becoming computer-minders ???
2
@Scott Hiddelston A Boeing 737 does not offer the same kind of sensory perception that something like a Cessna offers. In a Cessna, the yoke is mechanically connected to the ailerons and elevator through linkages. You can physically feel the wind traveling over the control surfaces.
With a B737 (or any airline jet, really), the yoke interacts with sensors that activate servos on the wings and tail. This type is called "fly-by-wire".
When you're climbing out of 5,000 feet as this flight was and suddenly the aircraft's climb performance dwindles to nothing, there can be a dozen reasons why. The only indications that you have as a pilot to determine the cause are the readouts in the cockpit and the knowledge that you have about how the plane reacts to those readouts.
It seems like the pilots were not aware about this plane's automatic stall prevention system, which engaged itself due to the faulty AOA sensor and began trimming the plane nose down.
To answer your question, yes, pilots absolutely are computer minders. They have to deal with dozens of inputs and outputs at all times in order to maintain the safe operation of the plane, and when the behavior of the plane is undocumented, that makes the job of the pilot much harder (obviously).
1
Robber Barons really know how to save other Robber Barons money.
The article says, "Boeing has been selling the model that crashed, the new 737 Max 8, as requiring little additional pilot training for airlines that already use the previous version of the plane."
Sure. Why spend money training pilots? In time use of the planes will bring problems to light and they can be fixed then. Lives lost? Who cares?
WE THE PEOPLE - average people around the world who are the ones losing OUR lives because of their greed - must DEMAND tough regulation for ALL airplanes.
In the meantime, Robber Baron investors can be the first and only passengers onboard until the "bugs" are worked out.
4