3 ms·

What is never mentioned is that since forever runaway stabilizer is one of the FEW memory items. Here it is. To be qualified as a pilot you have to have this m

What is never mentioned is that since forever runaway stabilizer is one of the FEW memory items. Here it is. To be qualified as a pilot you have to have this memorized. I. Runaway Stabilizer CONTROL COLUMN - HOLD FIRMLY AUTOPILOT (if engaged) - DISENGAGE Do not re-engage the autopilot. If the Runaway Continues STAB TRIM CUTOUT SWITCHES (both) - CUTOUT All this drama around "fighting the controls" and "fighting the plane" is weird. This is not some procedure you need to lookup, this is one of a few memory items.

ratsimihah 8y ago
That would make sense. Do you think they lacked experience or received improper training? From what I remember when preparing for the helicopter license, it was emphasized that being able to use manual sensors and controls was critical in case of such failures.
- privateSFacct 8y ago
  A couple of factors played into this. Terrible maintenance (well known issue with this airline). Seriously, a plane in US is HIGHLY unlikely to fly this many times with this type of issue. So in the US, risk of this even happening is MUCH lower. We don't hear about the situations pilots respond properly too. Despite the other person correcting me, most pilots do know this stuff in US. Go arounds, single engine landings, stab trim cutout etc all happen with some frequency. Runaway stabilizer has a cutout switch and wheel for a reason, the manual control you describe. It's actually a memory item - memory or recall items are used for time critical situations with risks of severe aircraft damage. You do the memory items and then look at checklist. There are not that many. My own view here - despite what others are saying, if pilots had cut out the electric trim, they would have been fine. 99% of time flights go per the plan and are boring, so pilots do sometimes take shortcuts. They don't brief the flight properly, they don't maintain a sterile cockpit, they don't look over past issues on a plane before takeoff (maintenance log book) and they don't follow procedures exactly. Planes are so safe a lot of pilots lean HEAVILY on the automation. So I'd be very curious about cockpit voice recorder. It seems almost impossible to go 12 minutes without doing the 20 second memory item. An example - properly using an elevator - you hit the button, when doors open, you enter. If doors closing you hit the button outside again or hit the door hold button inside and then enter or WAIT if doors don't open. The sensors in the door to avoid crushing you are meant as a backup. BUT, folks are so confident in those backup sensors they skip the procedure, and actually stick their hand into a closing door on purpose to keep it open. It works 99% of time I'm sure - but there will be that .01% where it doesn't. That's like flying. 99.999% it actually works if you take a shortcut (ie, in many cases you can cut out trim with control column input). But that IS NOT the actual procedure. So you see pilots say things like, "I've always done it this way", and yeah, it works 99.9% of the time BUT the designers intended you to follow the damn procedure - in which case you'll almost never have a problem. Another problem, you remember what you do. So if you are used to cutting out stab trim with control column as a shortcut and not switches, then yes, you could be in trouble here, especially if you never fall back to the actual procedure. There was a change here which mean more cases in which stab trim would be flight commanded and some shortcuts wouldn't work on it.
dingaling 8y ago
That process isn't sufficient on the 737Max. That is the point; to make it fly like a 737NG Boeing added an additional system, MCAS, that requires the AoA sensors to be manually disconnected during a malfunction or it will continue commanding elevator pitch. You could run through your memory drill as many times as you like, it wouldn't have helped in this case.
- privateSFacct 8y ago
  I hope this level of training isn't common with pilots - if so we are in trouble! Seriously. This is basic 101 type stuff, and if pilots have this little clue, we need to work to get them out of the cockpit. "requires AoA sensors be manually disconnected" ? Where is this coming from? "it will continue commanding elevator pitch" even though stab cutout?? Uh? Again, do you have a citation here? Seriously, where / what airline is training that? The airworthiness directive literally says - don't forget to follow the runaway stabilizer procedure in this situation. That is LITERALLY what Boeing and FAA are saying, and now you are telling us this other stuff? Pilot training in the US has gotten terrible!
- mannykannot 8y ago
  The FAA Airworthiness Directive (2018-23-51) can be found at the address below (pdf). There is no mention of manually disconnecting the AofA sensors. The addition to the Airplane Flight Manual required by the AD explicitly says "do the existing AFM Runaway Stabilizer procedure above, ensuring that the STAB TRIM CUTOUT are set to CUTOUT and stay in the CUTOUT position for the remainder of the flight." While I don't think pilot training is the only issue, we can't assume a crash was the most probable outcome following from the failure of the AofA indicator in question. https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/fe8237743be9b8968625835b004fc051/$FILE/2018-23-51.pdf https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf...

ratsimihah 8y ago

That would make sense. Do you think they lacked experience or received improper training? From what I remember when preparing for the helicopter license, it was emphasized that being able to use manual sensors and controls was critical in case of such failures.

privateSFacct 8y ago
A couple of factors played into this. Terrible maintenance (well known issue with this airline). Seriously, a plane in US is HIGHLY unlikely to fly this many times with this type of issue. So in the US, risk of this even happening is MUCH lower. We don't hear about the situations pilots respond properly too. Despite the other person correcting me, most pilots do know this stuff in US. Go arounds, single engine landings, stab trim cutout etc all happen with some frequency. Runaway stabilizer has a cutout switch and wheel for a reason, the manual control you describe. It's actually a memory item - memory or recall items are used for time critical situations with risks of severe aircraft damage. You do the memory items and then look at checklist. There are not that many. My own view here - despite what others are saying, if pilots had cut out the electric trim, they would have been fine. 99% of time flights go per the plan and are boring, so pilots do sometimes take shortcuts. They don't brief the flight properly, they don't maintain a sterile cockpit, they don't look over past issues on a plane before takeoff (maintenance log book) and they don't follow procedures exactly. Planes are so safe a lot of pilots lean HEAVILY on the automation. So I'd be very curious about cockpit voice recorder. It seems almost impossible to go 12 minutes without doing the 20 second memory item. An example - properly using an elevator - you hit the button, when doors open, you enter. If doors closing you hit the button outside again or hit the door hold button inside and then enter or WAIT if doors don't open. The sensors in the door to avoid crushing you are meant as a backup. BUT, folks are so confident in those backup sensors they skip the procedure, and actually stick their hand into a closing door on purpose to keep it open. It works 99% of time I'm sure - but there will be that .01% where it doesn't. That's like flying. 99.999% it actually works if you take a shortcut (ie, in many cases you can cut out trim with control column input). But that IS NOT the actual procedure. So you see pilots say things like, "I've always done it this way", and yeah, it works 99.9% of the time BUT the designers intended you to follow the damn procedure - in which case you'll almost never have a problem. Another problem, you remember what you do. So if you are used to cutting out stab trim with control column as a shortcut and not switches, then yes, you could be in trouble here, especially if you never fall back to the actual procedure. There was a change here which mean more cases in which stab trim would be flight commanded and some shortcuts wouldn't work on it.

dingaling 8y ago

That process isn't sufficient on the 737Max. That is the point; to make it fly like a 737NG Boeing added an additional system, MCAS, that requires the AoA sensors to be manually disconnected during a malfunction or it will continue commanding elevator pitch. You could run through your memory drill as many times as you like, it wouldn't have helped in this case.

privateSFacct 8y ago
I hope this level of training isn't common with pilots - if so we are in trouble! Seriously. This is basic 101 type stuff, and if pilots have this little clue, we need to work to get them out of the cockpit. "requires AoA sensors be manually disconnected" ? Where is this coming from? "it will continue commanding elevator pitch" even though stab cutout?? Uh? Again, do you have a citation here? Seriously, where / what airline is training that? The airworthiness directive literally says - don't forget to follow the runaway stabilizer procedure in this situation. That is LITERALLY what Boeing and FAA are saying, and now you are telling us this other stuff? Pilot training in the US has gotten terrible!
mannykannot 8y ago
The FAA Airworthiness Directive (2018-23-51) can be found at the address below (pdf). There is no mention of manually disconnecting the AofA sensors. The addition to the Airplane Flight Manual required by the AD explicitly says "do the existing AFM Runaway Stabilizer procedure above, ensuring that the STAB TRIM CUTOUT are set to CUTOUT and stay in the CUTOUT position for the remainder of the flight." While I don't think pilot training is the only issue, we can't assume a crash was the most probable outcome following from the failure of the AofA indicator in question. https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/fe8237743be9b8968625835b004fc051/$FILE/2018-23-51.pdf https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf...