3 ms·

Is this a joke? ERROR: Literally the first paragraph of the EAD is about controlling airspeed. [Edit: This is not correct] They hit 700(!!) MPH. They literall

Is this a joke? ERROR: Literally the first paragraph of the EAD is about controlling airspeed. [Edit: This is not correct] They hit 700(!!) MPH. They literally commanded full take off power to accelerate the plane into the ground. You can add power if your pitch is high to arrest a sink rate (ie, during landing), but if you are pitched down, you pull power. There is also a 300 second limit on T/O power - I'd be interested if they exceeded that as well. The maintenance on this plane was terrible. This was not a situation where folks involved "did everything right". For those not familiar, approx 3 minutes after they did a stab trim cutout they put stab trim back to normal. That's never been in any guidance for EAD or runaway. The 4th activation of MCAS moved trim down (to 1 unit, should have probably been at 4.3 - 5.x or so). That probably doomed them.

ummonk 5y ago
The first paragraph of the EAD is: "Disengage autopilot and control airplane pitch attitude with control column and main electric trim as required. If relaxing the column causes the trim to move, set stabilizer trim switches to CUTOUT. If runaway continues, hold the stabilizer trim wheel against rotation and trim the airplane manually."
- WalterBright 5y ago
  The entire EAD must be read, not the first paragraph. Including the digressions (your phrase). It's only two pages. I am not a pilot. But I am an aerospace engineer who worked on critical flight detail designs. You've likely flown on my work. My father was a pilot for the AF for 20 years. You don't get to be an old pilot if you don't pay attention 100% to the instructions and training. Flying isn't like driving a car. Humans are not natural flyers. You rarely get a second chance if you make a mistake flying. Maybe 90% of flight training is dealing with emergencies. If you're not dedicated to doing it right, and doing it 100%, every time, you've got no business being a pilot with hundreds of lives depending on you. P.S. I've gone flying with pilot friends many times. I watch them do the preflight. If they're not 100% perfect with it, I'm getting off.
  - slownews45 5y ago
    One advantage in flying - you are pretty much told EXACTLY how to do many things. This is what makes me think flying will be automatable. There are a lot of checklists already written for almost everything. Ie, electrical power up, preflights, (CDU preflight?) before taxi before takeoff etc. Runaway trim was a memory item (!). ie, so important you have to have it memorized. What's interesting is that because of a jammed actuator motor in an earlier US situation (way back) they have this language about a "maximum two person effort will not break the cables" https://1.bp.blogspot.com/-_jY4nvLmuE4/XQ_n-FaocOI/AAAAAAAAGSw/zpVbp0h6GFYPgv3ILgaWKNjoy7pQK4o7gCLcBGAs/s1600/Screen%2BShot%2B2019-06-23%2Bat%2B1.56.15%2BPM.png https://1.bp.blogspot.com/-_jY4nvLmuE4/XQ_n-FaocOI/AAAAAAAAG... This is because you have to basically break out of a clutch and friction condition if a motor seized which aside from the MCAS crashes could require pretty large efforts. There is evidence of somewhat routine stab trim issues, at least 1x per year mistrim stuff, and more often inop etc. Before these crashes I don't think it was considered even a very serious concern because pilots would handle it in ordinary course of things.
    - WalterBright 5y ago
      > One advantage in flying - you are pretty much told EXACTLY how to do many things. Experience shows that will get you safely out of the vast majority of emergency conditions. The ones that are left require understanding and a brain, which is why we still have human pilots. Runaway stab trim is so serious a condition that the cutoff switches are within easy reach right there on the console. It doesn't really matter how many safeguards there are against runaway trim, the pilot needs to be able to just turn the thing off. It's also deliberate that the electric trim switches override everything but the cutoff switches. Pure speculation on my part, but I suspect that Boeing thought that it was so easy to just turn off a misbehaving trim system, that the pilots would just do that. It's sort of like one day I was working away on my desktop, and smoke started boiling out of the case. My first reaction was to pull the plug out. Fortunately, that stopped the fire. If it hadn't, my second reaction would have been to throw the box outside. My lawnmower, power tools, etc., are all designed so that chopping the power to them is as easy as possible. Even race cars have a large switch mounted on the exterior to shut off all power.

ummonk 5y ago

The first paragraph of the EAD is: "Disengage autopilot and control airplane pitch attitude with control column and main electric trim as required. If relaxing the column causes the trim to move, set stabilizer trim switches to CUTOUT. If runaway continues, hold the stabilizer trim wheel against rotation and trim the airplane manually."

WalterBright 5y ago
The entire EAD must be read, not the first paragraph. Including the digressions (your phrase). It's only two pages. I am not a pilot. But I am an aerospace engineer who worked on critical flight detail designs. You've likely flown on my work. My father was a pilot for the AF for 20 years. You don't get to be an old pilot if you don't pay attention 100% to the instructions and training. Flying isn't like driving a car. Humans are not natural flyers. You rarely get a second chance if you make a mistake flying. Maybe 90% of flight training is dealing with emergencies. If you're not dedicated to doing it right, and doing it 100%, every time, you've got no business being a pilot with hundreds of lives depending on you. P.S. I've gone flying with pilot friends many times. I watch them do the preflight. If they're not 100% perfect with it, I'm getting off.
- slownews45 5y ago
  One advantage in flying - you are pretty much told EXACTLY how to do many things. This is what makes me think flying will be automatable. There are a lot of checklists already written for almost everything. Ie, electrical power up, preflights, (CDU preflight?) before taxi before takeoff etc. Runaway trim was a memory item (!). ie, so important you have to have it memorized. What's interesting is that because of a jammed actuator motor in an earlier US situation (way back) they have this language about a "maximum two person effort will not break the cables" https://1.bp.blogspot.com/-_jY4nvLmuE4/XQ_n-FaocOI/AAAAAAAAGSw/zpVbp0h6GFYPgv3ILgaWKNjoy7pQK4o7gCLcBGAs/s1600/Screen%2BShot%2B2019-06-23%2Bat%2B1.56.15%2BPM.png https://1.bp.blogspot.com/-_jY4nvLmuE4/XQ_n-FaocOI/AAAAAAAAG... This is because you have to basically break out of a clutch and friction condition if a motor seized which aside from the MCAS crashes could require pretty large efforts. There is evidence of somewhat routine stab trim issues, at least 1x per year mistrim stuff, and more often inop etc. Before these crashes I don't think it was considered even a very serious concern because pilots would handle it in ordinary course of things.
  - WalterBright 5y ago
    > One advantage in flying - you are pretty much told EXACTLY how to do many things. Experience shows that will get you safely out of the vast majority of emergency conditions. The ones that are left require understanding and a brain, which is why we still have human pilots. Runaway stab trim is so serious a condition that the cutoff switches are within easy reach right there on the console. It doesn't really matter how many safeguards there are against runaway trim, the pilot needs to be able to just turn the thing off. It's also deliberate that the electric trim switches override everything but the cutoff switches. Pure speculation on my part, but I suspect that Boeing thought that it was so easy to just turn off a misbehaving trim system, that the pilots would just do that. It's sort of like one day I was working away on my desktop, and smoke started boiling out of the case. My first reaction was to pull the plug out. Fortunately, that stopped the fire. If it hadn't, my second reaction would have been to throw the box outside. My lawnmower, power tools, etc., are all designed so that chopping the power to them is as easy as possible. Even race cars have a large switch mounted on the exterior to shut off all power.