A component of the crash(es) is that the trim wheel (what your co-pilot is manually winding at 0:42) has a smaller diameter on the Max than earlier models, and therefore the manual winding loads are far higher. Both pilots could not exert sufficient force to alter the stab trim, as well as fly the aeroplane.
As I understand it: the later advice on MCAS trim runaway was to use the electric trim to stabilise THEN isolate stab trim. Or it would have been if the aircraft hadn't been grounded Accident aircraft could not manually retrim due to excessive forces on the trim wheel by the time they shut it off, hence re-engaging elec trim. MCAS also appeared to have access to faster trim speed than elec trim
The crew in the second crash (Ethiopian) let aircraft speed build to nearly 400 kts due to leaving the engine power at Takeoff setting. At those speeds the only way to use manual trim inputs is probably using the "roller coaster" technique, which is not suitable for low altitude.
I'm sure you probably know by now but those pilot were dealing with multiple warning lights and alarms and the tab trim was not spinning constantly but in short bursts. Isn't the stab trim in the 737 Max different in that both switches shut off both electrical and AP. On his primary one is backup?
In the Ethiopian crash, the crew left engine power at Takeoff. Also, the First Officer did deactivate the 2 Stab Cutout switches, but only toward the very end of the event, instead of very early. He then quickly reactivated the switches, probably so the Captain could keep using the electric trim switches. At very the high airspeed it would take a world class body builder to manually trim the aircraft back toward nose level attitude. Not every crew that had the MCAS malfunction happen crashed.
Why was there no off switch for the MCAS only (without turning off the trim motors) is very concerning. A sign thay Boeing is relying on too much automation perhaps? Boeing must be punished for this.
Isn't it just common sense that once you cut off the trim stab it should return to the neutral position first before shutting off? This way you won't have to manually trim while it's shut off in a nose down position.
No. If it’s a runaway trim you should not trust it to return to its previous setting. Manual trimming is very easy and responds quickly. You can also feel the elevator pressure release on the yoke as your trimming making it very easy to return the aircraft to straight and level.
@@firstname5556 Not true. Just because the Ethiopian crew was unable to do it doesn’t make it so. A runaway trim scenario has immediate action items listed in the QRH (Quick reference handbook) and is a memory item to be performed in the event of a runaway trim. When completed in a timely manner, as it should, trimming the aircraft is easy. Waiting too long to perform the immediate action items will be more difficult but not impossible. There are maneuvers called the yo-yo, slowing the airplane to help relieve elevator forces, etc. (Google it for an explanation) Also because the two manual trim wheels, available to both pilots, are interconnected, both pilots can trim the airplane together to overcome the pitch forces.
@@billyjack3361 No matter how you try to cut it. Boeing created a highly dangerous software PAIRED WITH suboptimal physical design AND actively concealed the system that even their OWN test pilots admitted are unpredictable and unsafe. Their own risk assessment revealed catastrophic result every other year. If that isn't a WTF for you then I don't know what is. And you're here blaming the pilots for this unsafe technology, really? The pilots and the passengers shouldn't even have to deal with such unnecessary danger in the FIRST place and that plane SHOULDN'T have been in the market if the FAA weren't so useless. The least Boeing could do is inform pilots about such a travesty of engineering design. You expect pilots who were deliberately have not been made aware of the aggressiveness of this new software to react as if it was protocol while several different alarms blaring in a matter of seconds at the busiest phase of the flight or they'll face "unrecoverable consequence in less than 10 secs". I've never seen such a traitorous death sentence. That thing should have come with a BIG FAT RED WARNING and not purposely hidden by the imbeciles in Boeing. The responsibility for these deaths are squarely and no other than lies on the manufacturers. In fact, this should be a criminal act.
The computer/motors will no longer control the trim wheels. You can still manually trim the aircraft by moving the trim wheel with your hands. You can see that being done by the co-pilot when he leans forward, unfolds the manual trim arm (which is attached to the trim wheel and usually folded away during automatic operation) and begins to add nose-up trim. You can tell when that happens because it looks like he's rolling up the window of a car.
How many planes crashed because of all this auto-stuff which overrides the pilot's controls. Abysmal this crap. There always ought to be a feature to turn that off in the blink of an eye. And when it occurs and meddles with your controls you can just hope for being at high enough altitude to counteract in time. How's that even allowed to be installed in airliners to have this bird take over the controls and ram itself into the ground, into mountains, stalls and whatnot. Unbelievable. Great, helpful videos, as always, Cpt! I like this format a lot.
Thanks for showing those unfamiliar how simple it is to stop runaway trim. Abnormals were memory items for my airline. In my opinion, poor pilot training caused both crashes. I believe Boeing won’t say that for fear of losing customers. BTW- 22 years 727, 13 years 747 retired Captain. Also, the pilot flying ALWAYS trims the airplane, unless of course if it is too difficult to move by one person.
Hi Captain Jack, I wonder if you could offer your opinion on the possible cause of the China Eastern Airlines MU5735 crash yesterday? If we rule out the deliberate nose down theory, then how likely is the crash caused by failing handling of the runaway trim? Thank you in advance!
@@yangjiao9136 First let me say that I offer my condolences to those family members and friends who lost loved ones due to this tragedy. I wish I could help with an opinion as to the cause of this crash but that would be pure speculation. Too little is known, as of today, to offer an accurate assessment of the crash. Only after the FDR (Flight Data Recorder) and CVR (Cockpit Voice Recorder) are retrieved and analyzed will we have a better idea of the cause. I will be looking forward with anticipation to all additional information as it is released. Best wishes.
@@billyjack3361 Boeing caused the crash, not pilots. A safety system that relies on a single sensor is an appaling violation of long standing engineering principle. Not to mention that Boeing concealed MCAS from pilots and mocked airlines who requested sims for the max models. Boeing's own test pilot described the MCAS as agressive and unpredictable. Ultimately Boeing paid the price, it must hurt them now to see how popular A320neo is.
@@firstname5556 If the pilots didn’t cause the crash then how did the Lion Air crew who previously flew the accident airplane suffer the same ‘runaway trim” but successfully land the airplane with any problem? Answer…they knew the QRH and performed the immediate action item as per the manual. Something all trained air crew should know. Also, all airline pilots go through ‘differences’ training. It is required when a crew is moving to an airplane that is ‘different’ in some way. There is no need to know the intricacies of the MCAS system. We are not engineers. We are pilots. We need to know what the system does and how to shut it off. And that is clearly written in the manuals. I don’t believe the Boeing chief pilot said the MCAS system is unpredictable. Please include the publication you got that from. As far a being aggressive? If the airplane is stalling I would hope it is aggressive. The A320 has had its share of problems and continues to do so. Remember the Paris air show? The pilots had NO control of the airplane because the computer took over. Except for the MAX, the 737 continues to outsell the Airbus A320.
@@billyjack3361 You have to remember the role of the AOA sensor. It wasn't malfunctioning the flight before that's why they were able to land safely. It's practically impossible to land it safely with the AOA and the MCAS going haywire. Definitely not the pilots fault. Being a telecommunications engineer, I can tell you that every engineering student knows how to prevent a single point of failure. Boeing must have employed accountants instead of engineers to the engineering work. I'm glad that the only party that was charged by the court was Boeing, neither of the two airlines were charged.
Excellent video! It has been my experience that US pilots are superior to hand flying skills on 73s and there will always be newer and ever changing auto pilot modes and software mechanisms like MCAS, but as pilots we must always train on hand flying the airplane as you did here with immediate stab trim cut outs and performing the upset recovery by hand flying.
Ummmmmmm...the pilots on the lion air were trained in US....and pilot training is pretty standardized across the world...the US pilots don't get any more or less time "hand flying ". Sorry buddy...bet US is better at other things
@@amreekmann6537right and China Air manual on CRM was very small a decade back and American Airlines was 800 pages long. Hard to convince me the training and CRM is the same compared to the US
@@PeteCantillon oh ya..china sucked few years back. agree with you on that...however FAA helped set up the Regulations for China and now they are strict(er) than any other country
Loving these short little videos that just focus on just the one subject. Thanks!
A component of the crash(es) is that the trim wheel (what your co-pilot is manually winding at 0:42) has a smaller diameter on the Max than earlier models, and therefore the manual winding loads are far higher. Both pilots could not exert sufficient force to alter the stab trim, as well as fly the aeroplane.
The smaller trim wheel has been standard since the 737-300.
As I understand it: the later advice on MCAS trim runaway was to use the electric trim to stabilise THEN isolate stab trim. Or it would have been if the aircraft hadn't been grounded
Accident aircraft could not manually retrim due to excessive forces on the trim wheel by the time they shut it off, hence re-engaging elec trim.
MCAS also appeared to have access to faster trim speed than elec trim
The crew in the second crash (Ethiopian) let aircraft speed build to nearly 400 kts due to leaving the engine power at Takeoff setting. At those speeds the only way to use manual trim inputs is probably using the "roller coaster" technique, which is not suitable for low altitude.
What was the airspeed at that time, did those pilots monitor their altitude and airspeed, that should give them an idea on what to do.
Mcas
too much noise in the video. can't hear u talk
I'm sure you probably know by now but those pilot were dealing with multiple warning lights and alarms and the tab trim was not spinning constantly but in short bursts. Isn't the stab trim in the 737 Max different in that both switches shut off both electrical and AP. On his primary one is backup?
Do you do flight training on the side still? Would love to have an instructor like you!
Unfortunately not. I wish I had time to instruct...
Very good explanation, thank you.
Great video
In the Ethiopian crash, the crew left engine power at Takeoff. Also, the First Officer did deactivate the 2 Stab Cutout switches, but only toward the very end of the event, instead of very early. He then quickly reactivated the switches, probably so the Captain could keep using the electric trim switches. At very the high airspeed it would take a world class body builder to manually trim the aircraft back toward nose level attitude.
Not every crew that had the MCAS malfunction happen crashed.
Why was there no off switch for the MCAS only (without turning off the trim motors) is very concerning. A sign thay Boeing is relying on too much automation perhaps? Boeing must be punished for this.
@@aqimjulayhi8798 Because Boeing wanted to conceal that system. The pilots didn't even know about it in detail.
You shouldn't be designing a system that doesn't work and create another system to fix that system that has failed.
What kind system design is this?
@@aqimjulayhi8798 you don't need it.
Isn't it just common sense that once you cut off the trim stab it should return to the neutral position first before shutting off? This way you won't have to manually trim while it's shut off in a nose down position.
No. If it’s a runaway trim you should not trust it to return to its previous setting. Manual trimming is very easy and responds quickly. You can also feel the elevator pressure release on the yoke as your trimming making it very easy to return the aircraft to straight and level.
@@billyjack3361 Manual trimming is impossible if the plane is travelling at high speed at low altitude. This was the case with the Ethiopian max.
@@firstname5556 Not true. Just because the Ethiopian crew was unable to do it doesn’t make it so. A runaway trim scenario has immediate action items listed in the QRH (Quick reference handbook) and is a memory item to be performed in the event of a runaway trim. When completed in a timely manner, as it should, trimming the aircraft is easy. Waiting too long to perform the immediate action items will be more difficult but not impossible. There are maneuvers called the yo-yo, slowing the airplane to help relieve elevator forces, etc. (Google it for an explanation) Also because the two manual trim wheels, available to both pilots, are interconnected, both pilots can trim the airplane together to overcome the pitch forces.
@@billyjack3361 No matter how you try to cut it. Boeing created a highly dangerous software PAIRED WITH suboptimal physical design AND actively concealed the system that even their OWN test pilots admitted are unpredictable and unsafe. Their own risk assessment revealed catastrophic result every other year. If that isn't a WTF for you then I don't know what is. And you're here blaming the pilots for this unsafe technology, really? The pilots and the passengers shouldn't even have to deal with such unnecessary danger in the FIRST place and that plane SHOULDN'T have been in the market if the FAA weren't so useless. The least Boeing could do is inform pilots about such a travesty of engineering design. You expect pilots who were deliberately have not been made aware of the aggressiveness of this new software to react as if it was protocol while several different alarms blaring in a matter of seconds at the busiest phase of the flight or they'll face "unrecoverable consequence in less than 10 secs". I've never seen such a traitorous death sentence. That thing should have come with a BIG FAT RED WARNING and not purposely hidden by the imbeciles in Boeing. The responsibility for these deaths are squarely and no other than lies on the manufacturers. In fact, this should be a criminal act.
Thank you for the video!
Is the STAB CUTOUT switch new or is that the fix to the whole grounding issue and the countless lives lost?
It’s been on the 737 for as long as I’ve been flying it
Been there since the inception. All the way back to the 737-100.
So if this issue happens, you switch stab cutoff to off but are you stuck with a frozen trim or can you switch to a backup?
The computer/motors will no longer control the trim wheels. You can still manually trim the aircraft by moving the trim wheel with your hands. You can see that being done by the co-pilot when he leans forward, unfolds the manual trim arm (which is attached to the trim wheel and usually folded away during automatic operation) and begins to add nose-up trim. You can tell when that happens because it looks like he's rolling up the window of a car.
The ‘Stab Trim cutout switches’ are on all Boeing aircraft starting with the 707 and continued with the 727 and 747 I flew.
How many planes crashed because of all this auto-stuff which overrides the pilot's controls. Abysmal this crap. There always ought to be a feature to turn that off in the blink of an eye. And when it occurs and meddles with your controls you can just hope for being at high enough altitude to counteract in time. How's that even allowed to be installed in airliners to have this bird take over the controls and ram itself into the ground, into mountains, stalls and whatnot. Unbelievable.
Great, helpful videos, as always, Cpt! I like this format a lot.
Thanks for showing those unfamiliar how simple it is to stop runaway trim. Abnormals were memory items for my airline. In my opinion, poor pilot training caused both crashes. I believe Boeing won’t say that for fear of losing customers.
BTW- 22 years 727, 13 years 747 retired Captain. Also, the pilot flying ALWAYS trims the airplane, unless of course if it is too difficult to move by one person.
Hi Captain Jack, I wonder if you could offer your opinion on the possible cause of the China Eastern Airlines MU5735 crash yesterday? If we rule out the deliberate nose down theory, then how likely is the crash caused by failing handling of the runaway trim? Thank you in advance!
@@yangjiao9136 First let me say that I offer my condolences to those family members and friends who lost loved ones due to this tragedy.
I wish I could help with an opinion as to the cause of this crash but that would be pure speculation. Too little is known, as of today, to offer an accurate assessment of the crash. Only after the FDR (Flight Data Recorder) and CVR (Cockpit Voice Recorder) are retrieved and analyzed will we have a better idea of the cause. I will be looking forward with anticipation to all additional information as it is released.
Best wishes.
@@billyjack3361 Boeing caused the crash, not pilots. A safety system that relies on a single sensor is an appaling violation of long standing engineering principle. Not to mention that Boeing concealed MCAS from pilots and mocked airlines who requested sims for the max models. Boeing's own test pilot described the MCAS as agressive and unpredictable. Ultimately Boeing paid the price, it must hurt them now to see how popular A320neo is.
@@firstname5556 If the pilots didn’t cause the crash then how did the Lion Air crew who previously flew the accident airplane suffer the same ‘runaway trim” but successfully land the airplane with any problem? Answer…they knew the QRH and performed the immediate action item as per the manual. Something all trained air crew should know.
Also, all airline pilots go through ‘differences’ training. It is required when a crew is moving to an airplane that is ‘different’ in some way.
There is no need to know the intricacies of the MCAS system. We are not engineers. We are pilots. We need to know what the system does and how to shut it off. And that is clearly written in the manuals.
I don’t believe the Boeing chief pilot said the MCAS system is unpredictable. Please include the publication you got that from. As far a being aggressive? If the airplane is stalling I would hope it is aggressive.
The A320 has had its share of problems and continues to do so. Remember the Paris air show? The pilots had NO control of the airplane because the computer took over.
Except for the MAX, the 737 continues to outsell the Airbus A320.
@@billyjack3361 You have to remember the role of the AOA sensor. It wasn't malfunctioning the flight before that's why they were able to land safely. It's practically impossible to land it safely with the AOA and the MCAS going haywire. Definitely not the pilots fault. Being a telecommunications engineer, I can tell you that every engineering student knows how to prevent a single point of failure. Boeing must have employed accountants instead of engineers to the engineering work. I'm glad that the only party that was charged by the court was Boeing, neither of the two airlines were charged.
Excellent video! It has been my experience that US pilots are superior to hand flying skills on 73s and there will always be newer and ever changing auto pilot modes and software mechanisms like MCAS, but as pilots we must always train on hand flying the airplane as you did here with immediate stab trim cut outs and performing the upset recovery by hand flying.
Ummmmmmm...the pilots on the lion air were trained in US....and pilot training is pretty standardized across the world...the US pilots don't get any more or less time "hand flying ".
Sorry buddy...bet US is better at other things
@@amreekmann6537right and China Air manual on CRM was very small a decade back and American Airlines was 800 pages long. Hard to convince me the training and CRM is the same compared to the US
@@PeteCantillon oh ya..china sucked few years back. agree with you on that...however FAA helped set up the Regulations for China and now they are strict(er) than any other country