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

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

Post by FICU »

Manual electric trim is the electric trim on the yoke with the auto pilot disengaged. Boeing calls it “Main electric trim”.

Manual trim is using the stab trim wheel handles.

When the electric trim is running away you disengage auto pilot and auto throttles and use the electric trim manually which stops the trim runaway and allows nose up trim. You trim to a stabilized state and disconnect the stab trim, both autopilot and main electric trim switches.
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Last edited by FICU on Mon Jan 02, 2023 9:18 pm, edited 1 time in total.
boeingboy
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by boeingboy »

pelmet wrote: Mon Jan 02, 2023 4:06 pm
FICU wrote: Mon Jan 02, 2023 12:45 am
pelmet wrote: Sun Jan 01, 2023 7:21 pm I haven't read the report but I think the Ethiopian crew did perform the action to turn off the stab switches and the stop automatic, intermittent nose-down trimming but found that a large pull force was required to not descend. Their attempt to manually trim nose-up was unsuccessful so they selected the trim switches back on in order to be able to electrically trim nose up but that allowed the trim to automatically go further nose-down creating nose down forces beyond their control.
The manual nose up electric trim will over ride the MCAS nose down trim from what I understand, just as it does in a normal stab trim runaway. The procedure is to use manual electric trim to trim back to a stabilized condition then shut off the trim switches and manually trim with the handle on the trim wheel from then on. The big mistake the Ethiopian crew did was to not control the thrust by shutting off the auto-throttles and bringing the thrust back to help control the speed. MCAS and how it was handled was a factor but the thrust mismanagement was huge.

Ultimately, the first MCAS runaway on the Lion Air jet was handled and managed and the aircraft landed safely so it was possible to save the aircraft. Unfortunately the second Lion Air crew and the Ethiopian crew were not able to do it.
I don’t think there is such a thing as manual electric trim.

If I remember correctly, the excess speed led to higher forces on the stab preventing manual trim, which is already a difficult thing to operate. That is why the switches were selected back on. But one would think that electric nose up trim could have been used at that point but I’m not sure what the result is when the MCAS input is trimming the opposite way.

If MCAS is automatically trimming nose down and the pilot selects nose up trim with the electric switches - the stab will trim for nose up. In fact this is what it was doing as shown by the FDR. Why the pilots only trimmed half the time the airplane had trimmed nose down is unknown.

In the case of the Lion air crash - the captain was manually flying the aircraft against MCAS while he tried to get his useless first officer to actually do something useful. He flew it at 6000 feet for 6 min before he finally turned control over to the first officer to find the appropriate checklist items and complete the memory items. His first officer froze on the controls and 30 secs later he splashed it.

The aircraft was always recoverable...no matter how badly the design was fumbled - the crew actions ultimately doomed both flights.
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by HavaJava »

Spot on BoeingBoy. In both cases the aircraft could have been brought back into trim with manual electric trim and then “stabilizer cutout” used.

Basic airmanship followed by a simple memory item would have saved the day.

I also flew the A320 which for a while had a memory item where if the airplane went into a uncommanded dive you had to shut off 2 air data computers. That’s just as bad or worse than the MCAS issue. Airbus just got lucky.
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by digits_ »

HavaJava wrote: Tue Jan 03, 2023 8:12 am I also flew the A320 which for a while had a memory item where if the airplane went into a uncommanded dive you had to shut off 2 air data computers. That’s just as bad or worse than the MCAS issue. Airbus just got lucky.
Does that system on the A320 rely on the data from only one AoA sensor?
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by HavaJava »

digits_ wrote: Tue Jan 03, 2023 8:15 am
HavaJava wrote: Tue Jan 03, 2023 8:12 am I also flew the A320 which for a while had a memory item where if the airplane went into a uncommanded dive you had to shut off 2 air data computers. That’s just as bad or worse than the MCAS issue. Airbus just got lucky.
Does that system on the A320 rely on the data from only one AoA sensor?
Can’t remember as it was 8 years ago, but there was an ATB on the A320 for almost 2 years regarding this uncommanded dive issue. Doesn’t really matter at the end of the day because both aircraft had situations which cause uncommanded dives and according to some so called “professional” pilots would require god-like airmanship to overcome. Airbus just got lucky that none of the pilots who experienced their faults fucked up like the Lion or Ethiopian guys. But don’t kid yourself…that was just pure, dumb luck.
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by digits_ »

HavaJava wrote: Tue Jan 03, 2023 8:36 am
digits_ wrote: Tue Jan 03, 2023 8:15 am
HavaJava wrote: Tue Jan 03, 2023 8:12 am I also flew the A320 which for a while had a memory item where if the airplane went into a uncommanded dive you had to shut off 2 air data computers. That’s just as bad or worse than the MCAS issue. Airbus just got lucky.
Does that system on the A320 rely on the data from only one AoA sensor?
Can’t remember as it was 8 years ago, but there was an ATB on the A320 for almost 2 years regarding this uncommanded dive issue. Doesn’t really matter at the end of the day because both aircraft had situations which cause uncommanded dives and according to some so called “professional” pilots would require god-like airmanship to overcome. Airbus just got lucky that none of the pilots who experienced their faults fucked up like the Lion or Ethiopian guys. But don’t kid yourself…that was just pure, dumb luck.
You can influence luck by not having your system fail if one sensor fails. I doubt the A320 had 5 uncommanded dive issues in the first 5 months it hit the market.

If we assume the same competence level for pilots flying the 737 and 320, and only the 737s had deadly crashes, we could logically assume the 320 was designed better in this regard.
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by ogopogo »

Is it worth reading this again, now that the reports are out?

https://www.nytimes.com/2019/09/18/maga ... ashes.html
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by BTD »

Having flown the Max for 3 years as well as having done sim training, I have seen enough North American pilots make simple mistakes when they are distracted that put the airplane in some less then ideal places. In regards to the overspeed on Ethiopian I can’t tell you how many times I have seen a crew do a engine failure at v1 then at level off overlook for a short period that the autothrottle is off and pick up an extra 20 or 30 knots over what was planned. And that’s single engine.

While there are issues with training in that part of the world, these particular accidents to me are highlights of human factors and our limitations. Especially the Ethiopian. There are plenty of other accidents that show the culture/training issues. But When you have that many distractions coming at you that quickly, that close to the ground from a more or less unknown origin, I don’t think it matters where the crew is from, it’s a crap shoot whether they figure it out or not. We can look at many other North American carrier accidents where the crews have made bad decisions or miss managed the profile and they didn’t need MCAS to help them screw it up. They did it all on their own.

While Boeing screwed the pooch on the technical side, they really screwed the pooch of the human factors side. The crews could have flown the aircraft out of the situation for sure. But given all the distractions going on if we turn a blind eye to how a human responds to those distractions we are turning our backs on the biggest threat.

Even though Boeing has fixed that problem, at my airline, training put together an excellent flight control malfunction sim, that leaves me confident the crews could handle a similar situation. Prior to this I’m not so sure crews North American or otherwise would have a great batting average. The hard data already shows 2/3 of crews lost the battle.

I no longer fly the max, but the 737 has some gotchas on it. As do all other aircraft. Knowing the enemy is an important first step in combat. A benefit these crews didn’t really have.

Speaking of flaws. Here is a report that highlights a software problem that sat in the a320 FCCs for over 10 years before it became an issue. When the next one of these shows up (and it will) I wish the crew luck. It could be any one of us.

https://skybrary.aero/sites/default/fi ... lf/335.pdf
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by boeingboy »

Today - the French BEA released their comments on the Ethiopian final report....
The BEA notes that the contributing factors identified by the EAIB are only related to the MCAS system. The following contributing factors, that come out of the analysis of the event, should also be stated in the report:

1) Flight crew’s failure to apply, immediately after take-off and before the first MCAS activation, the Approach to Stall or Stall Recovery Maneuver and the Airspeed Unreliable Non-Normal Check-list;

2) Captain’s insistence on engaging the A/P, contrary to the Approach to Stall or Stall Recovery maneuver procedure;

3) Insufficient use of the electric trim to relieve the high control column forces after the MCAS nose down orders;

4) Captain’s lack of thrust reduction when the speed became excessive, which in combination with insufficient trim, caused an increase of the forces which became unmanageable on both the control column and the manual trim wheel.

5) The use of the Logipad system by the airline as the sole means to disseminate information on new systems and/or procedures, which doesn’t allow the evaluation the crews’ understanding and knowledge acquisition on new systems and procedures. This system was used to disseminate the information related to the MCAS system issued following the previous 737 Max accident and did not allow the airline to ensure that the crews had read and correctly understood this information.

All pretty damming against the crew and airline. Items 3 and 5 are ones I have been saying forever were big causes. Item 3 is basic airmanship - something every pilot learns from their first pilot lessons. Item 5 shows that even after the first one - Boeing put out information about the possible issues and how to deal with them. How the airlines informed and trained their crews is a big factor.
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by Eric Janson »

boeingboy wrote: Tue Jan 03, 2023 9:45 pm All pretty damming against the crew and airline. Items 3 and 5 are ones I have been saying forever were big causes. Item 3 is basic airmanship - something every pilot learns from their first pilot lessons. Item 5 shows that even after the first one - Boeing put out information about the possible issues and how to deal with them. How the airlines informed and trained their crews is a big factor.
I'd add item 2 - a huge issue which is not being addressed.

The autopilot is not longer being used as a tool - it is being used as a crutch to hide an inability to actually fly an airplane manually.

I've seen it over and over again - both in the Sim and in the aircraft.

https://www.smartcockpit.com/docs/Golden_Rules.pdf
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by sportingrifle »

Shortly after the 737-Max was grounded, the FAA did a study and concluded that if the aircraft was allowed to keep flying, even with the additional training that Boeing was proposing, an estimated further 6 hull losses would occur worldwide in the next 2 years.

That an airplane was ever certified when it was known that in the normal flight envelope the aerodynamic loads could overpower the manual trim system, speaks volumes to both how sub-standard the design is, and how much the FAA certification people lost the plot.
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by sportingrifle »

sportingrifle wrote: Sat Jan 07, 2023 12:39 am Shortly after the 737-Max was grounded, the FAA did a study and concluded that if the aircraft was allowed to keep flying, even with the additional training that Boeing was proposing, an estimated further 6 MCAS related hull losses would occur worldwide in the next 2 years.

That an airplane was ever certified when it was known that in the normal flight envelope the aerodynamic loads could overpower the manual trim system, speaks volumes to both how sub-standard the design is, and how much the FAA certification people lost the plot.
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by Eric Janson »

sportingrifle wrote: Sat Jan 07, 2023 12:39 am That an airplane was ever certified when it was known that in the normal flight envelope the aerodynamic loads could overpower the manual trim system, speaks volumes to both how sub-standard the design is, and how much the FAA certification people lost the plot.
Not a single person prosecuted - Dennis Muilenburg got a nice severence package.

Boeing paid some fines - production of these aircraft continue ( Boeing just got a waiver on the Max 7 and Max 10 otherwise they would have needed a complete cockpit re-design).

It's a disgrace.
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by ‘Bob’ »

Jail time is the only way these types of corporate shenanigans will stop.

Fines can be rationalized from a cost-benefit analysis and ultimately passed on to the consumer.

I think you'd see a rapid reduction in these types of things if those who made the decisions faced the modern day slavery that for-profit American prisons are allowed to have under the Thirteenth Amendment.
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Re: Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

Post by pelmet »

‘Bob’ wrote: Sun Jan 08, 2023 4:49 pm Jail time is the only way these types of corporate shenanigans will stop.

Fines can be rationalized from a cost-benefit analysis and ultimately passed on to the consumer.

I think you'd see a rapid reduction in these types of things if those who made the decisions faced the modern day slavery that for-profit American prisons are allowed to have under the Thirteenth Amendment.
Lots of Throw the Business Guys in Jail types out there. But what are the chances that if any of these types had ever in their life not written up a snag and just verbally passed it on, and if somehow it didn’t get fixed and combined with another fault, caused distraction leading to an accident, they would blame the accident pilot.
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