MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

[OldnGrounded]

"We simply don't know. We need to know." ~Takwis

Originally Posted by Icarus2001

Do WE really?

No we don't. YOU would like to know but you don't NEED to know.

Umm . . . What Takwis said we need to know is what Loose rivets wondered:

" . . . does the aircraft 'flop' nose-up in the late stages of stall entry?"

I'm pretty sure that the list of those who very definitely need to know is sufficiently long that it's perfectly reasonable to say that WE do.

And I predict that we will know, because there's no way, in view of the present and developing situation, that the information will be kept out of the public record.

[fgrieu]

Originally Posted by safetypee

..technical information from EASA @ https://aviationweek.com/commercial-...02a94c54606e9b

Nice article. Too bad the issue of the excessive effort to manually rotate the trim wheel in certain portions of the flight envelope was not raised. That might get in the way of lifting the ban, especially if the ET302 report comes out before the ban is lifted and contains damning material about that issue being a main contributing factor.

[safetypee]

fgrieu,

The runway trim situation could still be a problem, as you indicate re ET302.

My reading between the lines and from collated opinion, the combined software modifications and monitoring, stick base cutout switch, and a revised (clarified) procedure with refresher crew training, might balance the probability of malfunction - providing no MCAS failures. Even so this depends on human performance to shut the trim off before excessive trim forces would be encountered; perhaps with a big red light identifying trim runaway - but that would be challenging engineering task, dual FGCs at all times …
The training requirement could also apply to the NG, and previous variants.

[PPRuNe Towers]

fgrieu I think is referring to the various reports of a very stiff trim wheel at higher airspeeds. I've plenty of experience of 737NG post maintenance hydraulic flight controls switched off for trim checks but never above 250 knots. I've even repeated the test with the corrections applied in the wrong sense - very unpleasant but trim wheel's still usable.

Rob

[OldnGrounded]

Originally Posted by PPRuNe Towers

fgrieu I think is referring to the various reports of a very stiff trim wheel at higher airspeeds. I've plenty of experience of 737NG post maintenance hydraulic flight controls switched off for trim checks but never above 250 knots. I've even repeated the test with the corrections applied in the wrong sense - very unpleasant but trims wheel's still usable.

Rob

And probably never with the H-stab at or near the stops.

[568]

Originally Posted by Bend alot

There are far better ways to imply being a active commercial pilot on heavy aircraft if that is the case.

A simple check of your log book would prove your "every day" statement incorrect.

I will remind you that there have been many extremely informative posts on this thread, made by persons that certainly are not "Jet Transport /Airline Aircraft Pilots"

Big watches was a 90's thing.

Excellent response.

[568]

Originally Posted by Takwis

'We', certainly the 737 pilots here, DO need to know the handling characteristics of the aircraft, especially when simple malfunctions (loss of AOA) render the aircraft barely flyable. To say that we don't need to know is akin to saying we don't need to know what happens when an engine quits. We don't need to know how significant the yaw is, compared to other aircraft that we have flown? We don't need to know exactly how to handle it? Ridiculous.

Am I going to analyze the data myself, as someone suggested? No, I have neither the skills, nor the time for that. I have suggested, in the quote above, a body willing, able, and that has signaled a desire to do it. Has the data been gathered and analyzed before, of course it has. But those who did so have decided not to make it public...in fact kept their attempt to correct those flight characteristics secret as well, until people started dying. So, we need to rely on someone who is going to be honest and open.

I would say most of the posters here (including myself) would agree with your comments, great response.

[DaveReidUK]

Originally Posted by safetypee

Testing complete this month, certification approval in Jan, but more open-ended about training, simulators, overflights, and other regulators.

Hard to say whether that's posturing by the FAA, or AvWeek being creative. There is no way that the FAA is going to lift the grounding unilaterally if EASA, etc, are still weeks or even months away from doing so.

[Maninthebar]

Originally Posted by DaveReidUK

Hard to say whether that's posturing by the FAA, or AvWeek being creative. There is no way that the FAA is going to lift the grounding unilaterally if EASA, etc, are still weeks or even months away from doing so.

And, in a statement of the bleeding obvious, dependant on the outcome of testing this month. It would appear that parties have previously committed the fallacy of assuming the conclusion....

[Longtimer]

Position taken by Canadian FAs.

Media Advisory - Transport Canada will have to demonstrate that the Boeing 737 Max are safe to fly Français

NEWS PROVIDED BY

Canadian Union of Public Employees (CUPE) Nov 05, 2019, 10:37 ET

SHARE THIS ARTICLE

OTTAWA, Nov. 5, 2019 /CNW/ - The unions representing flight attendants at Air Canada, Sunwing and WestJet stand in solidarity with the American flight attendant unions who expressed safety concerns about the Boeing 737 Max flying again soon. The Air Canada Component of CUPE (Air Canada Mainline and Air Canada Rouge), CUPE local 4055 (Sunwing), and CUPE local 4070 (WestJet, WestJet Encore and Swoop) are calling on Transport Canada to take its responsibility in ensuring the safety of these aircraft.

The safety of passengers and crew must always come first. The federal government's decision to ground the Boeing 737 Max in Canada was the right thing to do. Given the record of Boeing and the Federal Aviation Administration in that file, it will now be up to Transport Canada to provide assurances that these aircraft are fully compliant and safe for our members and the travelling public.

Like the US flight attendant unions, CUPE must be consulted before Transport Canada makes the decision to allow the Boeing 737 Max to fly in our skies again. We need access to all the information required to assess the safety of these aircraft. The highest possible safety standards will be called for to avoid another tragedy. Simply stating these aircraft are safe does not make it so.

Air Canada, Sunwing, and WestJet are the three Canadian airlines operating the Boeing 737 Max. CUPE represents more than 13,000 flight attendants working at those airlines.

SOURCE Canadian Union of Public Employees (CUPE)

[infrequentflyer789]

Originally Posted by MurphyWasRight

Statement after the otherwise successful Starliner spacecraft pad abort test.

And of course the main competitor has one extra chute for more redundancy... (but still had a fail - in the one-chute-failed-by-design test...)

[safetypee]

Another view of the EASA comments:- https://www-rte-ie.cdn.ampproject.or...e/amp/1088643/
Return to service date not defined.
Focus on new software - Collins avionics.

[Flight Alloy]

One question if anyone could answer, is there a flight regime where the electric trim motors/their gear train would not have had the power to further manipulate the stab? Seeing how great the forces were, and even though the electric trim is electrically driven and aided I imagine by a reduction gear set, it would not seem to me to be multiple magnitudes more powerful than the handle+wheel-cable/pulley driven manual system (which itself is a lever and force reduction aided system (handle+wheel plus cable movement per turn vs pulley size on the jack screw drive side) with certain mechanical advantage). Could it be postulated that at a certain speed and AOA, the electric trim may have stalled out itself, unable to bring the stab nose up even if commanded, seeing that the manual system was practically seized?

[CurtainTwitcher]

A couple of articles on the stock buybacks and the financialization of industry and the effect on investment in Research & Development by investment fund manager Ben Hunt: When Was I Radicalized? (Boeing edition) To get the the full back story, read his previous article on Texas Instruments, Yeah, It's is still water.

[ARealTimTuffy]

Originally Posted by Flight Alloy

One question if anyone could answer, is there a flight regime where the electric trim motors/their gear train would not have had the power to further manipulate the stab? Seeing how great the forces were, and even though the electric trim is electrically driven and aided I imagine by a reduction gear set, it would not seem to me to be multiple magnitudes more powerful than the handle+wheel-cable/pulley driven manual system (which itself is a lever and force reduction aided system (handle+wheel plus cable movement per turn vs pulley size on the jack screw drive side) with certain mechanical advantage). Could it be postulated that at a certain speed and AOA, the electric trim may have stalled out itself, unable to bring the stab nose up even if commanded, seeing that the manual system was practically seized?

Not too likely. The electric motor is at the stab itself and the stab backdrives the trim wheels. The pilots are hand cranking the wheels about 100 feet away via cables. We simply don’t have the torque at that distance when out of trim. An electric motor has boat loads of torque and is connected more directly right at the stab.

edit: but it is of course still possible. Who knows anything at this point.

[CurtainTwitcher]

Thanks Gordon, links fixed.

[Phugoidinator]

Question About Stability

Stall at low altitude and airspeed not a good thing. Can this help explain why the second part of MCAS, for lower airspeeds, was added and made stronger than original MCAS? Are there data on this issue from wind tunnel tests or flight tests – does anyone know where I can find them?

[JPJP]

Originally Posted by 568

Sound comments.After hearing the response (s) from Muilenburg at the Congressional hearings, one has to wonder if the Board, senior bean counters and upper Management "types" have a grip on actual reality, after drinking the cool aid for all these years.I really believe that they are all in denial relating to the gravity of the current situation and what needs to be done to start the process of fixing many underlining issues (PR, MAX fix, law suits etc.).

I don’t think you’ll be surprised. But you may be disappointed. I was. Here is the boards view, and a ‘measure of their grip on reality’.

From the vantage point of our board, Dennis has done everything right," Calhoun said in an interview on CNBC. "Remember, Dennis didn't create this problem. From the beginning, he knew that MCAS could and should have been done better and he has led a program to rewrite MCAS to alleviate all of those conditions that ultimately beset two unfortunate crews and the families and victims."

https://www.cnbc.com/2019/11/05/boei...-for-2019.html

[Lake1952]

Originally Posted by Phugoidinator

Stall at low altitude and airspeed not a good thing. Can this help explain why the second part of MCAS, for lower airspeeds, was added and made stronger than original MCAS? Are there data on this issue from wind tunnel tests or flight tests – does anyone know where I can find them?

A behind the scenes software program that controls the entire HS and can point the nose down steeply towards the earth unannounced at low altitude is also not a good thing.

[568]

Originally Posted by JPJP

I don’t think you’ll be surprised. But you may be disappointed. I was. Here is the boards view, and a ‘measure of their grip on reality’.



https://www.cnbc.com/2019/11/05/boei...-for-2019.html

Appreciate the link, thanks.
One word, "unbelievable".
Unless they pull their heads out of their "you know what", I shudder to comprehend what lies beyond "Thunder dome" mark deux.