Ethiopian 737-800 Max crash - No survivors

[kgwilson]

And Boeings hole just got a bit deeper.

 

 

[Garfly]

[IBob]

Crikey...Ralph Nader. Author of 'Unsafe At Any Speed' 1965:

 

"The subject for which the book is probably most widely known, the rear-engined Chevrolet Corvair, is covered in Chapter 1—"The Sporty Corvair-The One-Car Accident". This relates to the first (1960–1964) models that had a swing axle suspension design which was prone to "tuck under" in certain circumstances. To make up for the cost-cutting lack of a front stabilizer bar (anti-roll bar), Corvairs required tire pressures which were outside of the tire manufacturers' recommended tolerances. The Corvair relied on an unusually high front to rear pressure differential (15psi front, 26psi rear, when cold; 18 psi and 30psi hot), and if one inflated the tires equally, as was standard practice for all other cars at the time, the result was a dangerous oversteer. Despite the fact that proper tire pressures were more critical than for contemporaneous designs, this was not clearly stated to Chevrolet salespeople and Corvair owners. According to the standards laid down by the relevant industry body, the Tire and Rim Association, the pressures also rendered the front tires overloaded when there were two or more passengers on board.

 

An unadvertised at-cost option (#696) included upgraded springs and dampers, front anti-roll bars and rear-axle-rebound straps to prevent tuck-under. Aftermarket kits were also available, such as the EMPI Camber Compensator, for the knowledgeable owner."

 

M...............

 

 

[fly_tornado]

WASHINGTON—A simulator session flown by a U.S.-based Boeing 737 MAX crew that mimicked a key portion of the Ethiopian Airlines Flight 302 (ET302) accident sequence suggests that the Ethiopian crew faced a near-impossible task of getting their 737 MAX 8 back under control, and underscores the importance of pilots understanding severe runaway trim recovery procedures.

 

Details of the session, shared with Aviation Week, were flown voluntarily as part of routine, recurrent training. Its purpose: practice recovering from a scenario in which the aircraft was out of trim and wanting to descend while flying at a high rate of speed. This is what the ET302 crew faced when it toggled cutout switches to de-power the MAX’s automatic stabilizer trim motor, disabling the maneuvering characteristics augmentation system (MCAS) that was erroneously trimming the horizontal stabilizer nose-down.

 

In such a scenario, once the trim motor is de-powered, the pilots must use the hand-operated manual trim wheels to adjust the stabilizers. But they also must keep the aircraft from descending by pulling back on the control columns to deflect the elevator portions of the stabilizer upward. Aerodynamic forces from the nose-up elevator deflection make the entire stabilizer more difficult to move, and higher airspeed exacerbates the issue.

 

The U.S. crew tested this by setting up a 737-Next Generation simulator at 10,000 ft., 250 kt. and 2 deg. nose up stabilizer trim. This is slightly higher altitude but otherwise similar to what the ET302 crew faced as it de-powered the trim motors 3 min. into the 6 min. flight, and about 1 min. after the first uncommanded MCAS input. Leading up to the scenario, the Ethiopian crew used column-mounted manual electric trim to counter some of the MCAS inputs, but did not get the aircraft back to level trim, as the 737 manual instructs before de-powering the stabilizer trim motor. The crew also did not reduce their unusually high speed.

 

What the U.S. crew found was eye-opening. Keeping the aircraft level required significant aft-column pressure by the captain, and aerodynamic forces prevented the first officer from moving the trim wheel a full turn. They resorted to a little-known procedure to regain control.

 

The crew repeatedly executed a three-step process known as the roller coaster. First, let the aircraft’s nose drop, removing elevator nose-down force. Second, crank the trim wheel, inputting nose-up stabilizer, as the aircraft descends. Third, pull back on the yokes to raise the nose and slow the descent. The excessive descent rates during the first two steps meant the crew got as low as 2,000 ft. during the recovery.

 

The Ethiopian Ministry of Transport preliminary report on the Mar. 10 ET302 accident suggests the crew attempted to use manual trim after de-powering the stabilizer motors, but determined it “was not working,” the report said. A constant trust setting at 94% N1 meant ET302’s airspeed increased to the 737 MAX’s maximum (Vmo), 340 kt., soon after the stabilizer trim motors were cut off, and did not drop below that level for the remainder of the flight. The pilots, struggling to keep the aircraft from descending, also maintained steady to strong aft control-column inputs from the time MCAS first fired through the end of the flight.

 

The U.S. crew’s session and a video posted recently by YouTube’s Mentour Pilot that shows a similar scenario inside a simulator suggest that the resulting forces on ET302’s stabilizer would have made it nearly impossible to move by hand.

 

Neither the current 737 flight manual nor any MCAS-related guidance issued by Boeing in the wake of the October 2018 crash of Lion Air Flight 610 (JT610), when MCAS first came to light for most pilots, discuss the roller-coaster procedure for recovering from severe out-of-trim conditions. The 737 manual explains that “effort required to manually rotate the stabilizer trim wheels may be higher under certain flight conditions,” but does not provide details.

 

The pilot who shared the scenario said he learned the roller coaster procedure from excerpts of a 737-200 manual posted in an online pilot forum in the wake of the MAX accidents. It is not taught at his airline.

 

Boeing’s assumption was that erroneous stabilizer nose-down inputs by MCAS, such as those experienced by both the JT610 and ET302 crews, would be diagnosed as runaway stabilizer. The checklist to counter runaway stabilizer includes using the cutout switches to de-power the stabilizer trim motor. The ET302 crew followed this, but not until the aircraft was severely out of trim following the MCAS inputs triggered by faulty angle-of-attack (AOA) data that told the system the aircraft’s nose was too high.

 

Unable to move the stabilizer manually, the ET302 crew moved the cutout switches to power the stabilizer trim motors—something the runaway stabilizer checklist states should not be done. While this enabled their column-mounted electric trim input switches, it also re-activated MCAS, which again received the faulty AOA data and trimmed the stabilizer nose down, leading to a fatal dive.

 

The simulator session underscored the importance of reacting quickly to uncommanded stabilizer movements and avoiding a severe out-of-trim condition, one of the pilots involved said. “I don’t think the situation would be survivable at 350 kt. and below 5,000 ft,” this pilot noted.

 

The ET302 crew climbed through 5,000 ft. shortly after de-powering the trim motors, and got to about 8,000 ft.—the same amount of altitude the U.S. crew used up during the roller-coaster maneuvers—before the final dive. A second pilot not involved in the session but who reviewed the scenario’s details said it highlighted several training opportunities.

 

“This is the sort of simulator experience airline crews need to gain an understanding of how runaway trim can make the aircraft very difficult to control, and how important it is to rehearse use of manual trim inputs,” this pilot said.

 

While Boeing’s runaway stabilizer checklist does not specify it, the second pilot recommended a maximum thrust of 75% N1 and a 4 deg. nose-up pitch to keep airspeed under control.

 

Boeing is developing modifications to MCAS, as well as additional training. Simulator sessions are expected to be integrated into recurrent training, and may be required by some regulators, and opted for by some airlines, before pilots are cleared to fly MAXs again. The MAX fleet has been grounded since mid-March, a direct result of the two accidents.

 

[/url]https://aviationweek.com/commercial-aviation/ethiopian-max-crash-simulator-scenario-stuns-pilots?NL=AW-05&Issue=AW-05_20190513_AW-05_525&sfvc4enews=42&cl=article_1&utm_rid=CPEN1000001417826&utm_campaign=19626&utm_medium=email&elq2=6dd9eec1bd614228a83b544a96f1e97d

 

 

[IBob]

I have read and watched pretty much all the stuff in this thread.

 

As an automation wonk, I would like to more fully understand the relationship between the pilot trim switches and the MCAS.

 

It has been stated at various points that operation of the trim switch cancels the MCAS response, but that the MCAS will then initiate another response 5(?) seconds later.

 

This can be read a number of different ways:

 

Do they mean the MCAS response must have begun for the trim switch to then cancel it?

 

Or will holding the trim switch activated prevent the MCAS response from starting?

 

Will the MCAS then initiate another response even if the switch is being held activated?

 

Or does it take a fresh activation of the trim switch to cancel each MCAS response.

 

And what happens to the trim while all this is going on:

 

If the MCAS tries to trim down, but the trim switch is activated up, is there then a manual trim up instead of the MCAS trim down? Or does the trim switch just cancel that MCAS cycle, and that's it?

 

This is only a partial list, but any combination of these or other possibilities would be simple to program into the automation.

 

I would like to know which ones were.

 

For me, this remains a small but import part of the whole tragic puzzle.

 

 

[Garfly]

[/url]https://www.nytimes.com/2019/05/14/business/boeing-737-max-ethiopian-plane-crash.html?action=click&module=Top%20Stories&pgtype=Homepage

 

 

[Thruster88]

If the MCAS tries to trim down, but the trim switch is activated up, is there then a manual trim up instead of the MCAS trim down? Or does the trim switch just cancel that MCAS cycle, and that's it?

Pilots manual trim switch(electric) overrides MCAS and allows the aircraft to be trimmed up, you can see this at

 

5:40:30. Not sure why they did not trim for longer until the trim indicator was neutral.

 

 

[IBob]

Pilots manual trim switch(electric) overrides MCAS and allows the aircraft to be trimmed up, you can see this at

 

5:40:30. Not sure why they did not trim for longer until the trim indicator was neutral. [ATTACH type=full" alt="ET302-FDR.jpg]42305[/ATTACH]

Yes, you're right.

 

What do you make of the 'Automatic Trim Command With No Change In Pitch Trim' at 5:40.45?

 

Presumably the servos were disabled at that point?

 

But why then were there not further 'Automatic Trim Command With No Change In Pitch Trim' events after that?

 

 

[Garfly]

[IBob]

I'd say good that the locals over there aren't trying to sweep it under the carpet.

 

 

[Bruce Tuncks]

Loading your plane outside of the prescribed limits is the easiest way to make it handle unpredictably.

Once a transport plane flown by a guy who later became very senior in the GFA nearly crashed in Africa. After weeks of putting the lettuce at the rear, the loaders put cucumbers there figuring that they were the same shade of green so therefore interchangeable. The pilot said it taught him a lesson about checking everything.

 

 

[IBob]

American Airlines union: blaming pilots for Boeing 737 Max crashes 'inexcusable'

 

[/url]https://www.theguardian.com/business/2019/may/23/boeing-737-max-crashes-american-airlines-pilots-union-mcas

 

 

[facthunter]

If they bust all the pilots unions there's no one to call this sort of thing out. Boeing have been trying to eliminate union influence in their newer factories and subbies for a while now. Anyone who whistle blows, Goes. Then add cost cutting, corner cutting. quality assurance goes out the window. Profit before all doesn't work especially in Aviation. I can't understand how people who would buy a good or a luxury car and put good tyres on it buy their airfares based just on which is cheapest.. ? Nev

 

 

[Bruce Tuncks]

The real blame lies with our system of over-regulation.

 

If there were no penalties for being honest, Boeing would never have had to withhold information like they did.

 

Over-regulation is the most dangerous thing I have to cope with in my personal flying. Yet it is hard to believe there is any evil genius behind it all. What we actually have is the unintended consequences law.

 

Here is an example of the unintended consequences law in operation... bike helmets are mandated to save lives. In fact they do the opposite, to the surprise of most people.

 

Rod Stiff believes in this law too. When asked about changes to the Jabiru, he said that every change brings about unforseen and undesirable changes. And the history of changes to the Jabiru bear this out. Jabiru were too fast, in hindsight, with some of the changes they made.

 

 

[facthunter]

To the contrary Bruce. One of the problems here was leaving too much of the self certification to Boeing and it's considered that the FAA failed due diligence and it s legal responsibilities in not being more thorough in it's overseeing of the operations by Boeing. FAA is very much under the spotlight here. Self regulation in aviation has proven to be a failed concept in notable cases. I'm afraid the saying "when the Cat's away, The MICE play" is a truism.. When shareholders DEMAND profit above all else, companies respond with cost cutting less staff less money paid to subbies etc. and your Quality Assurance is shot to pieces. and your reputation made over a companies lifetime is gone, and innocent people have died. Not that long ago Aviation( RPT )world wide had a year with NO deaths. That was REMARKABLE but hasn't been sustained by a log shot and may never be repeated.. Boeing's fuselages were separating into 3 sections on landing incidents/accidents with high forces but people didn't die luckily. This year is vastly different already. Did people relax a bit too much? Some of the signs were already there. Nev

 

 

[IBob]

The real blame lies with our system of over-regulation.

 

If there were no penalties for being honest, Boeing would never have had to withhold information like they did.

 

Over-regulation is the most dangerous thing I have to cope with in my personal flying. Yet it is hard to believe there is any evil genius behind it all. What we actually have is the unintended consequences law.

 

Here is an example of the unintended consequences law in operation... bike helmets are mandated to save lives. In fact they do the opposite, to the surprise of most people.

 

Rod Stiff believes in this law too. When asked about changes to the Jabiru, he said that every change brings about unforseen and undesirable changes. And the history of changes to the Jabiru bear this out. Jabiru were too fast, in hindsight, with some of the changes they made.

I think you raise a very valid point, Bruce. And I would think just about everyone here would agree that the regulation juggernaut is out of control.

 

However, my understanding is that the reason Boeing chose to do what they did was in order to market the Max as an aircraft requiring minimal retraining of flight crew. The penalty for being honest (as you put it) would have been the commercial disadvantage, not a regulatory one. Unless you are questioning the regulatory requirements for pilot training?

 

 

[kgwilson]

In simple terms Boeing f!#*@ed up big time by putting profit before safety. They are now trying desperately to minimise the disaster they created. Nev said this way back. "Boeing HAD a good reputation. Not any more. You cannot buy a reputation when you have thrown it away"

 

 

[derekliston]

In simple terms Boeing f!#*@ed up big time by putting profit before safety. They are now trying desperately to minimise the disaster they created. Nev said this way back. "Boeing HAD a good reputation. Not any more. You cannot buy a reputation when you have thrown it away"

Bit like the Australian cricket team!!!

 

 

[Bruce Tuncks]

I feel empathy towards those Boeing engineers. Raising the engines would not, in my opinion, have done that much harm, and when it led to ( surprising ) stability problems, I for one would have been convinced that a software fix was all that was necessary. How could raising the thrustline just a few inches cause a pitch up? I would have thought that a low thrustline would have a pitch-up moment, and this would be lessened a bit.

 

It was the secrecy of all this which did the harm. And why was there any need for secrecy? Because of the regulations. Regulations about crew training, for example.

 

 

[fly_tornado]

boeing are in a heap of legal trouble, some of the bigger airlines are going to be getting some free planes

 

 

[kasper]

I feel empathy towards those Boeing engineers. Raising the engines would not, in my opinion, have done that much harm, and when it led to ( surprising ) stability problems, I for one would have been convinced that a software fix was all that was necessary. How could raising the thrustline just a few inches cause a pitch up? I would have thought that a low thrustline would have a pitch-up moment, and this would be lessened a bit.

 

It was the secrecy of all this which did the harm. And why was there any need for secrecy? Because of the regulations. Regulations about crew training, for example.

Not so much regulations on crew training but a very strong marketing desire from Boeing. To counter the sales boom and market share that the A320 family had establish with a single training across most of the family Boeing has to maintain what has turned out to be the fiction that they too had crew commonality with little to no training.

 

The fiction was not from training requirements but from a sales requirement to have a extremely low training requirement they used to sell it into airlines as a practically nil training cost aircraft that cut seat miles with the new engines being so efficient.

 

Reality appears that the changes the new engines imposed required systems that from an external eye look poor - single point of failure - and it appears a difficulty of control fairly rapidly appearing even if the processes Boeing said to use.

 

When there is an automated system I would expect to know from training what it’s doing doing and what failure modes the system might have.

 

 

[Bruce Tuncks]

Quote

 

When there is an automated system I would expect to know from training what it’s doing doing and what failure modes the system might have.

 

That's my point: What made it costly for Boeing to do this? If it was the regulations, then those regulations are to blame. The point about training is exactly as things should be.

 

The situation is a bit like reporting of incidents in Australia. Personally, I would report to a forum like this in preference to the safety bureaucracy. I can imagine a situation where you could report an incident without fear of retribution, but that would require more trust than I have.

 

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[facthunter]

The OLD RAAUs leaked like a sieve. Perhaps because it was "matey" and smaller. But that's not acceptable. You must be able to trust the system but today which system can anybody trust? There is a "confidential" system in CASA. I don't know how good it is.

 

Whistleblowers don't get a good run in this modern world. In aviation learning from other's mistakes has been the cornerstone of progress in design and training and flight standards right from the beginning. Its the cheapest and best way in the long run. You don't live long enough to learn from your own mistakes. Don't think mistakes only happen to other (lesser)? Pilots either. Nev

 

 

[fly_tornado]

The Wall Street Journal (subscription required) is reporting the return to service of the Boeing 737 MAX is being pushed back because something in the investigation has prompted a review of training in the previous model. There are more than 5,000 Boeing 737NG models in use all over the world and the safety record of the type is considered good. The news clearly annoyed Boeing. “While we are working with the FAA to review all procedures, the safety of the 737 NG is not in question,” a Boeing spokesman told the Journal’s Andy Pasztor. The spokesman also noted “its 20-plus years of service and 200 million flight hours.” Earlier this week, acting FAA Administrator Dan Elwell said the FAA was going to take its time with the MAX investigation and he wasn’t concerned if it took another year.

 

The revisiting of procedures for a 20-year-old design was prompted by the fact that emergency training for the MAX was largely based on that from the NG. The NGs don’t have the MCAS system that is at the root of the investigation but the Journal says some of the MAX procedures are based on an assumption that pilots would know what to do (stabilizer trim cutoff switches) within seconds of the nose going down for no apparent reason. The Journal says the FAA is looking at whether the software fix for the MAX will give pilots more time, about 20 seconds, to react.

 

Meanwhile, pilots unions have told Boeing to stop blaming the pilots for the two fatal crashes that prompted this ever-expanding investigation. The crews of Lion Air 610 and Ethiopian Airlines 302 fought a losing battle to try and overcome the persistent nose-down actions of the MCAS resulting in 346 deaths and top Boeing officials have said some of that’s on the pilots. "Shame on you ... we're going to call you out on it," Dennis Tajer, head of the Allied Pilots Association, which represents American Airlines pilots, told CNN. "That's a poisoned, diseased philosophy."

 

 

[kgwilson]

The hole is not only getting deeper but wider as well.