Posted on 03/20/2019 12:18:50 PM PDT by centurion316
A few hours ago Bloomberg broke a story,
The Bloomberg story says that just one day before the fatal Lion Air accident, the very same airplane had suffered a similar pitch-control anomaly. But in this preceding case, an additional pilot, riding in the jump seat of the cockpit, recognized the problem and overrode part of the errant control system. The plane flew on to its destination.
The Bloomberg story says:
As the Lion Air crew fought to control their diving Boeing Co. 737 Max 8, they got help from an unexpected source: an off-duty pilot who happened to be riding in the cockpit.
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, -SNIP-
If true, this detail would shed light on -SNIP-: whether its pilots did not know how to override or offset a failing system, or whether they knew what to do but could not achieve it, because the command systems failed to respond or stop the descent.
Again if true, :
That one specific aircraft—not the 737 Max model line as a whole, but the specific airplane that eventually crashed—had an instrument failure, presumably the “angle of attack” indicator that triggered the automatic pitch-control system. It would suggest that the instrument failed one day; the flight crew coped; the same airplane was sent up with the same failure-prone sensor the next day; and this time the results were tragically different.
That flight crew training and familiarity played a fundamental role in the overall 737 Max drama. That is, a pilot who knew what was happening, could correct the situation; and pilots who didn’t, couldn’t, and flew to their (and their passengers’) deaths.
(Excerpt) Read more at theatlantic.com ...
You’re sitting there staring out the window not knowing that an off duty pilot just saved the plane from plummeting and ensuring your certain death.
Wow.
And yeah it’s like a Dodge where you can pull over and check the owner’s manual or read it when you get home at your leisure to find out why that orange light went on in your car.
It’s been known since the Lion Air accident that the aircraft experienced the same AoA sensor failure on the previous flight. The maintenance people supposedly fixed it. Also, I believe the previous day’s AoA sensor failure and in-flight problem was not reported to the crew who crashed the plane.
I believe the system over ride required only one switch (in plain view) to be activated. It appears that Boeing was less than proficient in making the malfunction systems problems and the cure properly emphasized to the pilots. (I was a fast-jet jock, not an airliner type, so these folks will describe things in better detail.)
However, in my types of planes, we had virtually no instrumented stall warning - only the slight shuddering (and heart stopping departures) to warn us that we just may have demanded too much AOA for our airspeed).
On the other hand, I cannot believe any pilots to be so incompetent that they’d stall a plane on takeoff and climb out. (At least, pilots trained either in our military or our civilian agencies.) As for some countries....)
I have a friend who flew for many years for Delta. He surmise that since these were airlines from third world countries, the pilots were either poorly trained, inexperienced or both.
“That one specific aircraft—not the 737 Max model line as a whole, but the specific airplane that eventually crashed—had an instrument failure, presumably the “angle of attack” indicator that triggered the automatic pitch-control system. It would suggest that the instrument failed one day; the flight crew coped; the same airplane was sent up with the same failure-prone sensor the next day; and this time the results were tragically different.”
Still, one wonders about redundancy with AOA indicators on this A/C. You would think that there would be several of these critical components on the plane and that the S/W would be cross-checking them against one another. And when the S/W observed an error, it would be reporting the failure to the pilots, and not just allow an automated process to continue. One that could crash the plane!
As for crew training, it looks to be deficient as well. Another case of too much reliance on automated systems and to little understanding of the need to cross-check with the basic flight instrumentation that is right there in front of them.
I remember those days “under the hood” doing unusual attitude recovery by reference to instruments. It takes some training to be good at it.
I do not know, I can only report on what I have read elsewhere. For the basic model of the 737 Max 8, only one AOA sensor was connected to the MCAS, the upgrade version had connections to two AOA sensors. Guess which version Lion Air bought?
Very sad if true, that this info was not passed along to the next flight crew.
“I do not know, I can only report on what I have read elsewhere. For the basic model of the 737 Max 8, only one AOA sensor was connected to the MCAS, the upgrade version had connections to two AOA sensors. Guess which version Lion Air bought?”
I don’t have access to a 737, but I can tell you that on our family’s Cessna Citation X, they are electro-mechanical device. So they have the reliability of a Hard Disk, hence the need for redundancy (not an extra-cost “feature,” as you suggest is the case with the MAX 8).
Many (most) media theories and commentary are ignorant (especially regarding whether the problem was with autopilot; the autopilot is not usually engaged until 10,000 ft)
The total cause of these flight accidents was the inability of the flight crews to Immediately disable the MCAS, which was not their fault.
Same thing happened with a Paris Air Show Airbus that flew into the trees because the pilots could not override the computer ‘guidance’. Look it up.
I know hindsight is 20/20 but didn’t i occur to the pilots that this should be reported right away and whoever received the information did something right away??
I can’t talk. I got a letter in the mail saying the airbag in my Challenger can shoot fragments into me and kill me possibly and I’ve not gotten the bag changed yet.
I may regret that in an accident!
Humans are a weak link in certain situations.
As I understand it, American Airlines is the only carrier so far that has ordered the MAX 8 with two sensors.
That crash did not occur at the Paris Air Show. It was a demonstration at a small airport air show with VIPs on board as passengers. Oui Too Low, a famous test pilot was flying that day.
Was it Southwest Airlines that modified its fleet of these aircraft to include a secondary AOA indicator?
Thanks. FYI, I’m not sure that real pilots are allowed on these aviation threads. It might offend the others.
OK, you are of course correct. I was just trying to point people toward the event which was part of the Paris Air Show venue.
(ddin’t realize Oui(we)TooLow had/has a certification in so many aircraft/countries!)
That’s his French cousin
Hilarious !
OK, dude, you win.
Maybe, that family should not be allowed in any cockpit.
(although in this case it seems so far that it was probably not the pilots’ fault).
One thing from my troubleshooting days as an aerospace engineer, sometimes when you find a problem, like a failed sensor you need to verify that this is the actual problem before you apply the “fix”.
In some cases, a bad ground wire can look like a bad sensor but changing out the sensor will not fix the problem. The next thing to do is test drive the fix.
A bad A o A sensor may not show up unless the plane is in flight. I suspect that taking the time for a test flight or waiting for the lab to confirm that the sensor that was removed was actually bad are things that could be omitted in the interest of getting the plane back in service.
All true, but there should be a procedure in the flight ops manual that outlines how the plane is to be flown absent a failed AoA sensor, and the operating crew, not a deadheading pilot should have known what to do. It is also troubling that the day earlier failure wasn't squawked to the airlines maintenance people and a determination made as to the airworthiness of the plane. I've been on planes where the ongoing legs of the flight were delayed so that maintenance could replace a faulty component. So here we are now with a bunch of dead people and the finger-pointing starting as to were the problem lies. And Boeing has the "deep pockets" so whether or not it's responsible, the ambulance chasing lawyers are beating a path to its door. along with European governments who see this as a way to make hay for Airbus.
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