That extra pilot, who was seated in the cockpit jumpseat, correctly diagnosed the problem and told the crew how to disable a malfunctioning flight-control system and save the plane, according to two people familiar with Indonesia's investigation.
The next day, under command of a different crew facing what investigators said was an identical malfunction, the jetliner crashed into the Java Sea killing all 189 aboard.
The previously undisclosed detail on the earlier Lion Air flight represents a new clue in the mystery of how some 737 Max pilots faced with the malfunction have been able to avert disaster while the others lost control of their planes and crashed.
The safety system, designed to keep planes from climbing too steeply and stalling, has come under scrutiny by investigators of the crash as well as a subsequent one less than five months later in Ethiopia. A malfunctioning sensor is believed to have tricked the Lion Air plane's computers into thinking it needed to automatically bring the nose down to avoid a stall.
If the same issue is also found to have helped bring down Ethiopian Airlines Flight 302, one of the most vexing questions crash investigators and aviation safety consultants are asking is why the pilots on that flight didn't perform the checklist that disables the system.
"After this horrific Lion Air accident, you'd think that everyone flying this airplane would know that's how you turn this off," said Steve Wallace, the former director of the U.S. Federal Aviation Administration's accident investigation branch.
The combination of factors required to bring down a plane in these circumstances suggests other issues may also have occurred in the Ethiopia crash, said Jeffrey Guzzetti, who also directed accident investigations at FAA and is now a consultant.
MCAS is driven by a single sensor near the nose that measures the so-called angle of attack, or whether air is flowing parallel to the length of the fuselage or at an angle. On the Lion Air flights, the angle-of-attack sensor had failed and was sending erroneous readings indicating the plane's nose was pointed dangerously upward.
Sometimes it's better that the pilot just fly the plane, without some computer trying to do it for him. It sounds like the dead head pilot had been properly trained, either by the company or on his own, but that training didn't extend to the crew flying the next day.
It sounds as if training was lacking. I'm not taking a shot at third world pilots, but none of these accidents occurred with first world pilots flying the same aircraft.
ReplyDeleteI believe you're absolutely correct, LL. This guy says the same thing, with a little bit more authority/expertise in the aircraft.
DeleteIt's an interesting question I just thought about. The international language for all air control is english but how many non-native english speakers actually sit down and read all the aircraft instructions, guides, bulletins etc if they are only in english? I don't know if Boeing and the rest translate their publications into the languages native to the countries where they sell their jets or not but I suspect not and that might be why EIBs and even urgent safety EIBs just don't get read by overseas non-english 'readers'. The pilot may speak english but they may hardly ever bother to read it. Yes, unprofessional in the extreme, but human.
DeleteHas Trump been blamed for these 2 fatal incidences yet?
ReplyDeleteReliance on a single sensor strikes me a foolish in a critical flight system.
ReplyDeleteInput from a friend: "This is the thing. In the USA, every pilot I know of no matter what airline they work for hand flies their aircraft up though 10,000 feet or even more. On approach, if it is VFR, shortly after glide slope intercept we disengage the A/P and hand fly it all the way down. We love to fly. We are trained to fly. We hand fly our aircraft all the time. On the 787 which I fly, we have a HUD which when hand flying, nails it “balls on”.....the first thing we do if the automation starts to do funny stuff is disconnect it and go back to the J-3 days.....needle ball and airspeed. Automatically....it is not even a thought process. If the automation is not doing what we want, we disconnect it, hand fly it and we do so until we figure out what is going on. This is the same for every major airline in the United States. European airlines are trained the same way. However, when you get to the Asian airlines, African airlines and some of the third world airlines......they are trained to put the A/P on at 200 feet and let the automation do the rest. If the automation screws up or if the “garbage in, garbage out” concept kicks in, they have no idea what to do. Unlike USA Airlines, their first thought is not to disconnect the automation because they have no idea what to do next. In the USA, we do. Believe me, I have had this happen a few times and the “fall back” is to go to stick and rudder. We have had at least two situations in the USA on the MAX where the automation did not perform to the pilot’s expectations. The pilots did what we are trained to do.....disconnect, hand fly, figure out the problem but fly the aircraft first. Personally, I would NEVER fly on an African airline. The F/O in this latest crash had 200 hours of flight time experience. That meant that the captain was on his own. I suspect that there was zero CRM involved......not good. People keep talking about these two “Stab Trim Runaway Switches”......yes, I have those too on the B-787 right by my right thigh......I have never used them. I don’t think this problem is a “runaway trim” problem. This is a case of a couple of “pilots”.......one, in the right seat with 200 hours of flight time taking off from a high altitude airport......perhaps getting a bit slow.....putting on the A/P at 200 feet or so and the airplane saying “we’re a bit slow so I am going to nose down to gain the proper airspeed” and the pilots panicking like “hey, our nose is going down!”.....and bad things happened after that. Does Boeing need to change the software? I think so.......for the plots in other countries who are not properly trained to fly an aircraft like this. Are USA pilots trained for this....yes.....but in the first place they usually do not put the A/P on at 200 feet and even if they did and the automated system did something weird, we are trained to disconnect the A/P and hand fly the aircraft and not fly it into the ground. This is my opinion only.....until the investigation comes out with the facts, I am not sure what truly happened. Until then, always, be cognizant of the airline you book your flight on. I would never fly on a third world airline."
ReplyDeleteI believe you are spot on.
DeleteThanks for the explanation and I wholeheartedly agree with your analysis.
DeleteAnd I agree with Rob also; evidently, the AOA was lying to the autopilot and not fixed.
I sometimes wonder if the aircraft are not getting TOO automated.
I was wondering about the maintenance, if the airplane tried to drive into the ground by itself one day and was saved by luck then did the same thing the next day ... it was not fixed.
ReplyDeleteThat HAD to be a safety of flight discrepancy...
I agree with Brig - from what I have read and heard, many, many, MANY Asian based airlines fly the computer, not the airplane. Additionally, they also have a "Boss is Right" mentality and are hesitant to question any authority figures - teachers, professors, parents, cops, or experienced pilots.
ReplyDeleteYou can see both of these issues in the Taiwan crash of several years ago (where the wrong engine was cut). The San Francisco B-777 crash shows it also - the airplane came in too low and the crew couldn't adjust in time.
Some people wonder if something similar could have happened with MH-370.
Additionally, third world maintenance attitudes come into play, and in some countries the aviation safety organization is pushed to go easy on their national carriers.
Unfortunately, I don't think it is a coincidence that 3 of the last 5 'major' airplane losses have been with Malaysian flagged aircraft.
Which is why I NEVER ever fly Air Guruda or SE Asian Airlines. I also have a story about Air Vanuatu - for another day. Best take a boat rather than fly those carriers.
DeleteIn automobiles, the throttle position sensor in the accelerator pedal has two opposing sensors. When you depress the the pedal the voltage in one sensor raises, and one lowers within a specified range. If these two sensors do not agree for more than a few milliseconds the system defaults to a "limp in" mode or derates the fuel.
ReplyDeleteThe fly by wire throttle body works in much the same way. It is designed to fail in a specific way to prevent a runaway vehicle or unwanted acceleration. I cannot understand why this attitude control system in an airplane would not be designed in the same way or even better.
But like I always say, I am just a dumb mechanic...
What do I know...
Jeremy P.