MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
Join Date: Jun 2019
Location: Tdot
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
Watched all 9 hrs of testimony the last 2 days.
Mr Muilenburg got it so wrong during the hearings. He could have come out looking way better for himself, but it seems he still doesn’t understand why the world is pissed. And there seems to be a lot he doesn’t know about going on around this case.
He he claimed to be unaware of Boeing’s attempts to move litigation to Indonesia vs the USA. I’d be surprised. This among so many others.
Mr Hamilton, on the other hand, seemed educated on the facts, remorseful, and truthful to the questioned being asked.
Mr Muilenburg got it so wrong during the hearings. He could have come out looking way better for himself, but it seems he still doesn’t understand why the world is pissed. And there seems to be a lot he doesn’t know about going on around this case.
He he claimed to be unaware of Boeing’s attempts to move litigation to Indonesia vs the USA. I’d be surprised. This among so many others.
Mr Hamilton, on the other hand, seemed educated on the facts, remorseful, and truthful to the questioned being asked.
Join Date: Sep 2019
Location: leftcoast
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
The ANU case is less demanding but still requires handling that is not part of the normal training of the flight crew by the airlines, it may be part of advanced training gained in military training. For the ANU case, rolling the aircraft into a turn will allow control of airspeed while sorting out the underlying control problem.
Join Date: Nov 2007
Location: australia
Posts: 168
Likes: 0
Received 0 Likes
on
0 Posts
I told the story here somewhere, of a late night test flight after an elevator pushrod installation ( the wrong way, unfortunately) When the mechanic turned off the hydraulic pumps to put us into manual reversion, there was an immediate forceful pitch-up. Both the Captain and I pushed forward with all our might, but didn’t really regain control until the mechanic got the pumps back on. As far as I can remember, recognition was instantaneous, the altitude gain was minimal, and the negative Gs put us put us light in the seats. It was all done in a few seconds. Fighting with something we didn’t understand, I am sure it would have been much more serious.
The purpose of the the Elevator Power Off Test is to see how many turns of the Stabiliser Trim Wheels it takes to trim the aircraft, from memory its about 2.5 turns, any more than that then adjustments have to be made.
These procedures are written in the AMM and also in the DDG.
Join Date: Dec 2011
Location: Ottawa, Canada
Posts: 28
Likes: 0
Received 0 Likes
on
0 Posts
Since Lion Air I can't get out of my mind how ludicrous it seems to use movement of the horizontal stab to correct control force non-linearity when there are much easier, more conventional and safer ways to do it. I accept that a software add-on to STS may be the cheapest approach but it is such a brutal solution it just doesn't compute. Unless it is not just non-linearity that is the problem. JATR suggested FAA determine the bare, un-enhanced stall characteristics of the MAX. Could it be that this airplane just doesn't stall safely? In that case Stall PREVENTION would indeed need a brutal approach.
737-MAX may have been mis-named. It should have been 737-2MUCH.
737-MAX may have been mis-named. It should have been 737-2MUCH.
Join Date: Oct 2019
Location: Great White North of the 49th
Posts: 77
Likes: 0
Received 0 Likes
on
0 Posts
From 42:30 onward needs to be played, replayed and looped over and over again to all the narrow minded share holder valued bean counters at Boeing. It’s talks about “why Americans make better aeroplanes”. Unfortunately his answer is not true today. This man is brilliant. Have a listen.
Since Lion Air I can't get out of my mind how ludicrous it seems to use movement of the horizontal stab to correct control force non-linearity when there are much easier, more conventional and safer ways to do it. I accept that a software add-on to STS may be the cheapest approach but it is such a brutal solution it just doesn't compute. Unless it is not just non-linearity that is the problem. JATR suggested FAA determine the bare, un-enhanced stall characteristics of the MAX. Could it be that this airplane just doesn't stall safely? In that case Stall PREVENTION would indeed need a brutal approach.
737-MAX may have been mis-named. It should have been 737-2MUCH.
737-MAX may have been mis-named. It should have been 737-2MUCH.
Thread Starter
Join Date: Apr 2015
Location: Under the radar, over the rainbow
Posts: 788
Likes: 0
Received 0 Likes
on
0 Posts
Since Lion Air I can't get out of my mind how ludicrous it seems to use movement of the horizontal stab to correct control force non-linearity when there are much easier, more conventional and safer ways to do it. I accept that a software add-on to STS may be the cheapest approach but it is such a brutal solution it just doesn't compute. Unless it is not just non-linearity that is the problem. JATR suggested FAA determine the bare, un-enhanced stall characteristics of the MAX. Could it be that this airplane just doesn't stall safely? In that case Stall PREVENTION would indeed need a brutal approach.
737-MAX may have been mis-named. It should have been 737-2MUCH.
737-MAX may have been mis-named. It should have been 737-2MUCH.
And, really, as ktcanuck says, MCAS is a sledgehammer solution for a rather delicate problem, if the problem really is stick force gradient.
I thought, when I first read it in the JATR report, that the recommendation to test the bare airframe was an indication that the Joint Authorities team has serious doubts about the MAX's stability in certain corners of the envelope. Reading it a couple more times hasn't changed the impression -- that was a very striking recommendation to include.
And, really, as ktcanuck says, MCAS is a sledgehammer solution for a rather delicate problem, if the problem really is stick force gradient.
And, really, as ktcanuck says, MCAS is a sledgehammer solution for a rather delicate problem, if the problem really is stick force gradient.
It is therefore unsurprising that certifying authorities would/should want to know what might be happen, and how air crew should respond, in the event of MCAS Fail Off
Join Date: Sep 2019
Location: Here
Age: 73
Posts: 238
Likes: 0
Received 0 Likes
on
0 Posts
The kicker to this is that Boeing engineers found that their original implementation (presumably not based on guesswork) was markedly insufficient to meet the need they had identified. Therefore a naive person might imagine that the 'delicate problem' as originally scoped turned out to be much more indelicate on the final airframe.
It is therefore unsurprising that certifying authorities would/should want to know what might be happen, and how air crew should respond, in the event of MCAS Fail Off
It is therefore unsurprising that certifying authorities would/should want to know what might be happen, and how air crew should respond, in the event of MCAS Fail Off
It occurs to me that the "bare airframe characteristics" issue may be at the bottom of the "phased approach" that Muilenburg talked about in the 3Q call, with FAA granting approval ahead of non-US regulators. Could the FAA be ready to accept Boeing's fail-safe Mk2 MCAS, with curbs and restraints imposed on the existing system and appropriate training, while ROW holds out for fail-operational Mk3, that also gets backfitted to the US fleet?
If so, there may be a long gap between FAA and ROW certification, and a lot of deeply unhappy bunnies in the global base, not to mention a Godawful image problem.
If so, there may be a long gap between FAA and ROW certification, and a lot of deeply unhappy bunnies in the global base, not to mention a Godawful image problem.
My question was not to do with either accident but the circumstances for which MCAS was designed to work. Its implementation suggests that Boeing did not believe that the Pitch and Power mantra would be insufficient support to air crews if they reached "certain corners of the envelope"
A technical point which I may have missed: with the stick full back, MCAS remained active, but the main electric trim is disabled by the lower stick cutout switch. In this condition would any pilot stick-top trim switch have any effect in moving the trim?
One version of ‘the drill’ required re-trimming before isolating the trim system; if as above, this would not be effective if the stick was already full back - MCAS failure.
Thus for any abnormality where the stick is full back, then the pilot cannot reduce stick force with electric trim - revert to manual wheel trim - if able, spare hands and difficult to move.
One version of ‘the drill’ required re-trimming before isolating the trim system; if as above, this would not be effective if the stick was already full back - MCAS failure.
Thus for any abnormality where the stick is full back, then the pilot cannot reduce stick force with electric trim - revert to manual wheel trim - if able, spare hands and difficult to move.
Join Date: Sep 2019
Location: Here
Age: 73
Posts: 238
Likes: 0
Received 0 Likes
on
0 Posts
My question was not to do with either accident but the circumstances for which MCAS was designed to work. Its implementation suggests that Boeing did not believe that the Pitch and Power mantra would be insufficient support to air crews if they reached "certain corners of the envelope"
Given that original mcas has it's own issues, an airspeed unreliable condition in takeoff configuration (as the cases under discussion) need to be handled with Pitch & Power until causes identified, no major changes in configuration and speed, will most likely end up in a return to dep rwy. (valid for FBW and conventional flight control system, sounds all over the cockpit increasing distraction and workload).
JATR are recommending that certifying authorities (re)consider the handling characteristics of the airframe in the case where MCAS does not activate WHEN IT IS DESIGNED TO.
Can you address that?
Join Date: Jul 2013
Location: Within AM radio broadcast range of downtown Chicago
Age: 71
Posts: 842
Received 0 Likes
on
0 Posts
Case to Indonesia?
I'd agree, Muilenburg's responses to inquiries about the company's legal manuever to try to move the Lion Air case(s) to Indonesia sounded like well-rehearsed segments from the obvious Damage Control/Speak Little script-playbook with which he had been coached and drilled.
Beyond that, it isn't up to Boeing, or any defendant in any type of lawsuit. It's a complicated procedural motion, one the judge decides based on a set of some six or eight factors (one reason it's complex is that how much weight to give to any one factor, or factors, can be disputed in a given lawsuit). For the officially inclined, it's a motion based on the legal doctrine of forum non conveniens.
The things that struck here as surprising were, first, the evidence about Boeing's design affairs, and its interactions with FAA (especially), is in the U.S. Hard to argue that this evidence would be equally accesible in discovery in the other forum (Indonesia) - even if we assume for the sake of talking about it, that the discovery process works the same there, which I seriously doubt. And without lurching into the pedantic, these motions often admit liability, short-circuiting the importance of discovery. I don't....quite see....Boeing admitting....liability in this matter......yet. (And if the plaintiffs seek discovery from and by the officials who worked on the JATR panel, which was conducted under U.S. federal agency processes....if I were the judge I'd tell Boeing to withdraw their motion as frivolous.)
So second, seems like a typical defense attorney stall manuever.
As a kicker, Sen. Blumenthal's efforts to get the Boeing CEO to say something unkind and derogagory about the Indonesia court system was comic relief, though tragicomic in essence.
Beyond that, it isn't up to Boeing, or any defendant in any type of lawsuit. It's a complicated procedural motion, one the judge decides based on a set of some six or eight factors (one reason it's complex is that how much weight to give to any one factor, or factors, can be disputed in a given lawsuit). For the officially inclined, it's a motion based on the legal doctrine of forum non conveniens.
The things that struck here as surprising were, first, the evidence about Boeing's design affairs, and its interactions with FAA (especially), is in the U.S. Hard to argue that this evidence would be equally accesible in discovery in the other forum (Indonesia) - even if we assume for the sake of talking about it, that the discovery process works the same there, which I seriously doubt. And without lurching into the pedantic, these motions often admit liability, short-circuiting the importance of discovery. I don't....quite see....Boeing admitting....liability in this matter......yet. (And if the plaintiffs seek discovery from and by the officials who worked on the JATR panel, which was conducted under U.S. federal agency processes....if I were the judge I'd tell Boeing to withdraw their motion as frivolous.)
So second, seems like a typical defense attorney stall manuever.
As a kicker, Sen. Blumenthal's efforts to get the Boeing CEO to say something unkind and derogagory about the Indonesia court system was comic relief, though tragicomic in essence.
Join Date: Mar 2019
Location: On the Ground
Posts: 155
Likes: 0
Received 0 Likes
on
0 Posts
Last edited by Takwis; 31st Oct 2019 at 14:48.
Join Date: Mar 2019
Location: On the Ground
Posts: 155
Likes: 0
Received 0 Likes
on
0 Posts
The elevator pushrods cannot be installed upside down.
The purpose of the the Elevator Power Off Test is to see how many turns of the Stabiliser Trim Wheels it takes to trim the aircraft, from memory its about 2.5 turns, any more than that then adjustments have to be made.
These procedures are written in the AMM and also in the DDG.
Last edited by Takwis; 31st Oct 2019 at 13:46.
Maybe you've overlooked the fact that this thread is about MCAS, Boeing's ridiculous, secret, flawed, killer system. MCAS took control of the pitch away from the pilots.
The results speak for themselves.
PS, added: I see the infant 'wunderkid' Twatsupheadsdown has confined their great wisdom almost entirely to solving all matters MCAS in a spirited burst of posting since joining.... all of 4 weeks ago. Didn't there used to be a forum dedicated to the sandpit, an aptly named arena for this one?
Last edited by pilotmike; 31st Oct 2019 at 13:50.
Join Date: Mar 2019
Location: French Alps
Posts: 326
Likes: 0
Received 0 Likes
on
0 Posts
The NTSB/JATR reports, as well as Hamilton's testimony on Wednesday, emphasized the fact that the MCAS misfire was never tested in the sim, let alone in flight. And that Boeing was not aware of the consequences.
They replaced it with a trim runaway event just to suit the assumptions.
So any "pitch and power" or "runaway trim" argument just misses the point.
Agree.
The NTSB/JATR reports, as well as Hamilton's testimony on Wednesday, emphasized the fact that the MCAS misfire was never tested in the sim, let alone in flight. And that Boeing was not aware of the consequences.
They replaced it with a trim runaway event just to suit the assumptions.
So any "pitch and power" or "runaway trim" argument just misses the point.
The NTSB/JATR reports, as well as Hamilton's testimony on Wednesday, emphasized the fact that the MCAS misfire was never tested in the sim, let alone in flight. And that Boeing was not aware of the consequences.
They replaced it with a trim runaway event just to suit the assumptions.
So any "pitch and power" or "runaway trim" argument just misses the point.
KNKT carried out test flights which included MCAS activation on the same terms as the accident flight - these were done with knowledge aforethought and demonstrated that if the event was expected then the outcome, though challenging, could be managed through application of the right NNCs in the right order.
None of which makes the implementation of MCAS 'right' - as previous posters have pointed out it is a system which is designed to run for 10 seconds in "normal" operation and yet a pilot is supposed to recognise runaway trim in 3 seconds. the information given to air crew on the operation of this system was minimal and no training was offered.
Boeing recognised that the system was powerful enough to pile an aircraft nose first into the ground and completely failed to assess the risk accurately