Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

[GRK2]

Wow...pretty cold. How about you don't talk about your awesome business prowess here on this site?

Nothing cold or prowess related about buying into a long term investment. Because they happened to be the manufacturer of the aircraft that crashed has nothing to do with investing in them.

Let me put it more simple terms there Tbay...this isn't the place for your investment tips...and yes, to tell us all how smart you think you are by posting your stock buying idea on an accident thread is purely chilling. Take it outside buddy, it doesn't belong here.

[CFM Symphony]

Wow...pretty cold. How about you don't talk about your awesome business prowess here on this site?

Nothing cold or prowess related about buying into a long term investment. Because they happened to be the manufacturer of the aircraft that crashed has nothing to do with investing in them.

There is nothing ethically wrong with investing in Boeing after this crash. However given the circumstances, I don't think bragging about it is in good taste. Show some class and tact please.

CFM

[Capt. Underpants]

Lets assume worst case scenario and its a faulty AOA sensor and a mishandled MCAS response. Emergency AD issued changing the FCC software and removing the MCAS trim inputs and the fleet is flying again. Long term it gets fixed with software or addition of a third AOA sensor. The aircraft will continue to be bought and put into service, same as the 787 after the battery issues got fixed.

MCAS was used to certify the flight envelope limitations on the MAX. You don't just "turn it off" and carry on as if nothing happened. Any changes to the system would require re-certification prior to release to the industry.

[Antique Pilot]

In 1985 I spent a few weeks in Ethiopia. I flew on a B-720 from Addis to Asmara Eritrea and back to Addis the next day. I met the crew at their layover hotel and they invited me for dinner. They were all very knowledgeable and professional. The captain had trained on F86’s in the USA in 1960. He also flew T-28’s for the Ethiopian Airforce. Anyways they were all very experienced. Back in Addis I was given a tour of their maintenance base. Again it was first rate, right up there with any major Western airline. I flew to Frankfurt on an ET B767. Flight was on time, service was excellent. I would fly with them anytime.

AP

[Meatservo]

Could someone put this MCAS thing into layperson's terms for us here? I've looked it up and what I have managed to figure out is that it's a modification made to the 737 that compensates for the increased effect that larger and more underslung engines have on longitudinal trim. Is this correct?

I wouldn't normally wish to speculate about accidents before the official reports are out, but the media are already starting to conflate the two recent 737 max-8 accidents and there's been a lot of talk on aviation forums about this MCAS system. How significant is the potential trim excursion from this system if it malfunctions? Is it possible for it to command full nose-up or nose-down trim? Is it impossible for pilots to use the conventional trim wheel to counteract it? I can see an uncommanded trim movement being a bit bewildering in an approach in IMC, but I have more trouble imagining its deadliness in VMC in the daytime, unless this thing is able to command huge trim changes.

I simply don't know enough about this system to understand some of the speculation or imagine how these two events could be related. Please don't jump all over me. I'm just trying to understand some if the ways the computer on a 737 can murder you without recourse to the manual flight controls. I operate a simpler aircraft on which the entire computerized control system including the automatic trim can be completely killed in one move.

[pilotbzh]

Apparently Cayman Airways has grounded their 737 max

https://mobile.twitter.com/CaymanAirway ... 0223787008

All 2 of them....

[ant_321]

Could someone put this MCAS thing into layperson's terms for us here? I've looked it up and what I have managed to figure out is that it's a modification made to the 737 that compensates for the increased effect that larger and more underslung engines have on longitudinal trim. Is this correct?

I wouldn't normally wish to speculate about accidents before the official reports are out, but the media are already starting to conflate the two recent 737 max-8 accidents and there's been a lot of talk on aviation forums about this MCAS system. How significant is the potential trim excursion from this system if it malfunctions? Is it possible for it to command full nose-up or nose-down trim? Is it impossible for pilots to use the conventional trim wheel to counteract it? I can see an uncommanded trim movement being a bit bewildering in an approach in IMC, but I have more trouble imagining its deadliness in VMC in the daytime, unless this thing is able to command huge trim changes.

I simply don't know enough about this system to understand some of the speculation or imagine how these two events could be related. Please don't jump all over me. I'm just trying to understand some if the ways the computer on a 737 can murder you without recourse to the manual flight controls. I operate a simpler aircraft on which the entire computerized control system including the automatic trim can be completely killed in one move.

After I read your post I found this post on social media from a company that makes a manual for pilots on the 737. It does a better job explaining it than I would.

LEAP-1B,
Due to different engine position (more forward) and nacelle shape of the LEAP engines the manoeuvring characteristics of 737 MAX have slightly changed, causing upward pitching moment. It became necessary to install MCAS (Maneuvering Characteristics Augmentation System) to compensate for this unique handling characteristics as part of the certification process.

MCAS is a function of FCC (Flight Control Computer) and takes Angle of Attack (AOA) data from Left AOA vane

MCAS activates automatically when all of the following conditions are met:
High angle of attack
Autopilot disengaged
Flaps are up

When the MCAS is active it trims nose down for up to 10 seconds.

Trimming nose up while the MCAS is active will pause the automatic MCAS nose down trim for up to 5 seconds. MCAS will restart nose down trim if the activation criteria are still met.

MCAS trims 0.27 units per second - up to 2.5 units in 10 second cycle

Erroneous high AOA data might cause un-commanded nose down trim through MCAS

MCAS can be disabled and automatic nose down trimming stopped by switching the Stabilizer Trim Cutout Switches to Cutout.

Long story short, you end up in a sort of “runaway trim” situation. The memory items for that are the same in every type I’ve flown. Hit the cutout switch and trim manually.

[FADEC]

We don't know what happened yet, but it seems there was a control problem.
Putting the MCAS system in and not putting it in the Flight Manual is ridiculous! Why?
Runaway MCAS should be trained for; repeatedly; can't do that if it is not in the Manual.
Hopefully if there is any indication of MCAS problems in the earliest results from the Flight/Voice Recorders the MAX will be grounded.

Remember that earlier 737's had an issue with rogue rudder actuators going hard over. Boeing denied all the evidence.
Several accidents and incidents were blamed on pilots until one crew managed to land an airplane with the malfunction and Boeing was exposed; forced to re-design the part.
Boeing claimed one of the accidents was a pilot committing suicide when the airplane rolled over and flew into the ground.

Boeing 747 engine mount "Fuse Pins" failed and caused a couple of fatals. Had to be re-designed.

Three 707's had the horizontal stabiliser snap off when landing flap was selected with bad results.

Regarding low time co-pilots. Hopefully that had nothing to do with it.
At one time, AC had lots of just over 250 hour pilots; there were several on my course. There was no problem.
Those pilots were mentored by experienced Captains.
I had the odd F/O with lots of time who was not good on a good day; hours were not the issue.
Lufthansa F/O's go on the line with 250 hours; that hasn't been a problem.
Grads from Sault, Seneca and the like are better trained than many of the low time F/O's that were on the line before those programs started.
Sometimes a higher time pilot has bad habits or attitudes that are a detriment.

[digits_]

MCAS can be disabled and automatic nose down trimming stopped by switching the Stabilizer Trim Cutout Switches to Cutout.

Is that the same button/linked to the autopilot disconnect? Or a switch that's somewhere out of easy reach on another panel? Is that the same switch you would use for a "normal" trim runaway?

Freaky to read that such a system is linked to only one AoA vane? After take-off, if you are flying manually, you raise the flaps, the left AoA is sending a wrong signal and off you go...

I hate to say it, but even the "newer" metros had better protection than that

[ant_321]

MCAS can be disabled and automatic nose down trimming stopped by switching the Stabilizer Trim Cutout Switches to Cutout.

Is that the same button/linked to the autopilot disconnect? Or a switch that's somewhere out of easy reach on another panel? Is that the same switch you would use for a "normal" trim runaway?

Freaky to read that such a system is linked to only one AoA vane? After take-off, if you are flying manually, you raise the flaps, the left AoA is sending a wrong signal and off you go...

I hate to say it, but even the "newer" metros had better protection than that

It’s on the center pedistal. Kind of under the thrust levers. Not exactly the most ideal location but not something you would have to look hard for. It would be difficult to be hand flying a very out of trim airplane and hit them yourself. If the PM wasn’t there to help you relatively quickly things could get interesting.

[telex]

[tsgas]

We don't know what happened yet, but it seems there was a control problem.
Putting the MCAS system in and not putting it in the Flight Manual is ridiculous! Why?
Runaway MCAS should be trained for; repeatedly; can't do that if it is not in the Manual.
Hopefully if there is any indication of MCAS problems in the earliest results from the Flight/Voice Recorders the MAX will be grounded.

Remember that earlier 737's had an issue with rogue rudder actuators going hard over. Boeing denied all the evidence.
Several accidents and incidents were blamed on pilots until one crew managed to land an airplane with the malfunction and Boeing was exposed; forced to re-design the part.
Boeing claimed one of the accidents was a pilot committing suicide when the airplane rolled over and flew into the ground.

Boeing 747 engine mount "Fuse Pins" failed and caused a couple of fatals. Had to be re-designed.

Three 707's had the horizontal stabiliser snap off when landing flap was selected with bad results.

Regarding low time co-pilots. Hopefully that had nothing to do with it.
At one time, AC had lots of just over 250 hour pilots; there were several on my course. There was no problem.
Those pilots were mentored by experienced Captains.
I had the odd F/O with lots of time who was not good on a good day; hours were not the issue.
Lufthansa F/O's go on the line with 250 hours; that hasn't been a problem.
Grads from Sault, Seneca and the like are better trained than many of the low time F/O's that were on the line before those programs started.
Sometimes a higher time pilot has bad habits or attitudes that are a detriment.

The FAA in the USA ,upped the minimum experience level to 1500 hrs based on it's concerns for flight safety.

[digits_]

Thanks for the picture.

Speculation, but I have a feeling that this would be exactly what happened, and Boeing will try to blame the crew for not pressing that switch quickly enough.

Any idea what the flap retraction altitude is at Ethiopian Airlines?
And the Lion air one?

[ant_321]

Thanks for the picture.

Speculation, but I have a feeling that this would be exactly what happened, and Boeing will try to blame the crew for not pressing that switch quickly enough.

Any idea what the flap retraction altitude is at Ethiopian Airlines?
And the Lion air one?

Most airlines use 800’ or 1000’. I’m not sure what they use.

[tbaylx]

Wow...pretty cold. How about you don't talk about your awesome business prowess here on this site?

Nothing cold or prowess related about buying into a long term investment. Because they happened to be the manufacturer of the aircraft that crashed has nothing to do with investing in them.

Let me put it more simple terms there Tbay...this isn't the place for your investment tips...and yes, to tell us all how smart you think you are by posting your stock buying idea on an accident thread is purely chilling. Take it outside buddy, it doesn't belong here.

Yup that's what I was doing, not replying to another post on the same subject. Chilling, simply callous and chilling.

[tbaylx]

Lets assume worst case scenario and its a faulty AOA sensor and a mishandled MCAS response. Emergency AD issued changing the FCC software and removing the MCAS trim inputs and the fleet is flying again. Long term it gets fixed with software or addition of a third AOA sensor. The aircraft will continue to be bought and put into service, same as the 787 after the battery issues got fixed.

MCAS was used to certify the flight envelope limitations on the MAX. You don't just "turn it off" and carry on as if nothing happened. Any changes to the system would require re-certification prior to release to the industry.

Not true, it just has to be approved. You don't have to re certify the entire aircraft. Same as when they redid the rudder PCU didn't require a complete re certification.

[Capt. Underpants]

MCAS was used to certify the flight envelope limitations on the MAX. You don't just "turn it off" and carry on as if nothing happened. Any changes to the system would require re-certification prior to release to the industry.

Not true, it just has to be approved. You don't have to re certify the entire aircraft. Same as when they redid the rudder PCU didn't require a complete re certification.

Partly. No, the whole flight test program wouldn't need to be redone. However, given the flight envelope implications and two fatal accidents in short succession, I'd bet the farm that FAA would require all MCAS-related certification flight tests to be redone.

[Meatservo]

Is there any evidence this MCAS thing was responsible for either accident? It sounds pretty easy to deal with.

[telex]

Is there any evidence this MCAS thing was responsible for either accident? It sounds pretty easy to deal with.

From another forum.

“And Boeing have still not explained the logic of of a pseudo-stick-push that keeps operating again and again and again, until you get full forward trim. Have you tried this MCAS-trim-runaway in the sim? According to the sim, the aircraft is only just about controllable with two gorillas hauling back in unison, with both feet up on the foot-bar and hauling about 40 kg pressure on each stick. And that was in level flight with the CofG in the central position. Ok, now try a recovery from a stall-dive, with a forward CofG, with 20º nose down pitch, and with the speed rapidly increasing to 250 kt. It is absolutely impossible - you are doomed. And doomed by an anti-stall system that is supposed to save you. But who in the world would want to recover from a stall, with the trim-stabiliser set fully forward? Who thought that ine up? The stabiliser is more powerful than the elevator, and will take you straight down to terra-firma. Heck, even the Wright Brothers knew not to design something like that.”

[tbaylx]

Is there any evidence this MCAS thing was responsible for either accident? It sounds pretty easy to deal with.

It certainly was a factor in the Lion Air, pure speculation with Ethiopian as no data recorder info has been released yet.

Either way you're correct though, it's a runaway stab regardless of what the root cause of the runaway is, the actions are the same.