Ethiopian airliner down in Africa
Join Date: Feb 2010
Location: Thailand
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
Boeing tumbled early Monday on heightened scrutiny by regulators and prosecutors over whether the approval process for the company’s 737 Max jetliner was flawed.
A person familiar with the matter on Sunday said that the U.S. Transportation Department’s Inspector General was examining the plane’s design certification before the second of two deadly crashes of the almost brand-new aircraft.
Separately, the Wall Street Journal reported that a grand jury in Washington, D.C., on March 11 issued a subpoena to at least one person involved in the development process of the Max. And a Seattle Times investigation found that U.S. regulators delegated much of the plane’s safety assessment to Boeing and that the company in turn delivered an analysis with crucial flaws.
737 Max Is Turning Into a Major Problem for Boeing | Time
A person familiar with the matter on Sunday said that the U.S. Transportation Department’s Inspector General was examining the plane’s design certification before the second of two deadly crashes of the almost brand-new aircraft.
Separately, the Wall Street Journal reported that a grand jury in Washington, D.C., on March 11 issued a subpoena to at least one person involved in the development process of the Max. And a Seattle Times investigation found that U.S. regulators delegated much of the plane’s safety assessment to Boeing and that the company in turn delivered an analysis with crucial flaws.
737 Max Is Turning Into a Major Problem for Boeing | Time
Join Date: Sep 2016
Location: USA
Posts: 803
Likes: 0
Received 0 Likes
on
0 Posts
And thrust always controls vertical flight path, so if they reduced thrust they would have only hit the ground sooner. In a desperate fight for altitude, "piloting" would dictate maximum thrust.
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,350
Likes: 0
Received 0 Likes
on
0 Posts
You're mistaken, "climbing" (or, put more precisely) elevator/AOA control always controls speed. Of course, under the likely MCAS scenario discussed, they did not have AOA control and the airspeed was running away from them.
And thrust always controls vertical flight path, so if they reduced thrust they would have only hit the ground sooner. In a desperate fight for altitude, "piloting" would dictate maximum thrust.
And thrust always controls vertical flight path, so if they reduced thrust they would have only hit the ground sooner. In a desperate fight for altitude, "piloting" would dictate maximum thrust.
You're mistaken, "climbing" (or, put more precisely) elevator/AOA control always controls speed. Of course, under the likely MCAS scenario discussed, they did not have AOA control and the airspeed was running away from them.
And thrust always controls vertical flight path, so if they reduced thrust they would have only hit the ground sooner. In a desperate fight for altitude, "piloting" would dictate maximum thrust.
And thrust always controls vertical flight path, so if they reduced thrust they would have only hit the ground sooner. In a desperate fight for altitude, "piloting" would dictate maximum thrust.
.
Gender Faculty Specialist
Gender Faculty Specialist
My experience of this is unusual attitude recovery during manual reversing air tests. Reducing thrust, if you're already using everything you have to keep the nose up, WILL result in a further nose down moment and no reduction in speed. They'd have been better off sticking the speed brakes up.
And in fact Boeing DO publish this in the QRH.
Join Date: Sep 2016
Location: USA
Posts: 803
Likes: 0
Received 0 Likes
on
0 Posts
Having taught out of control flight in high performance aircraft I can tell you we never taught that. It’s also not taught in current airline simulator training. It is not what Boeing puts out. The last thing you want with trim stuck or running nose down is excessive speed. You control that with thrust. Again it’s called piloting. Had they reduce thrust and kept the speed back below 250 they would not have hit the ground at all. Control forces would have been much lighter. You have to establish the aircraft in a regime where it is controllable. Max thrust is the worst thing you could do in a nose down trim situation.
Gender Faculty Specialist
Join Date: Sep 2016
Location: USA
Posts: 803
Likes: 0
Received 0 Likes
on
0 Posts
And to that end, I'm afraid spoilers won't help either, but they'll certainly be a lot less harmful than a thrust reduction with underslung engines.
Unless the pitching moment they add is nose up, which is an answer I don't know. But a nose up pitching moment is what we want, both for the instantaneous normal acceleration upward, and the energy-state perspective on reducing airspeed.
[/QUOTE]
Join Date: Nov 2018
Location: Jakarta
Posts: 20
Likes: 0
Received 0 Likes
on
0 Posts
It seems both aircraft were porpoising before going in. Is it possible the crews were trying to overcome excessive aerodynamic loads on the stabiliser which had gone towards the forward limit, after cutting electrical power to the stab trim motor and were now trying to wind manual trim during the unloading maneuver called roller coasting? See extract from a Boeing 737-200 PTM date 1982 and migrated from Tech Log
Extract from the Boeing 737-200 Pilot Training Manual February 1982 page 04.80.31. Edited for brevity
Runaway and Manual Stabiliser - Recovery from Severe Out-of-Trim
"In an extreme nose-up out-of-trim condition, requiring almost full forward control column, decelerate, extend the flaps and/or reduce thrust to a minimum practical setting consistent with flight conditions until elevator control is established. Do not decrease airspeed below the minimum maneuvering speed for the flap configuration. A bank of 30 degrees or more will relieve some force on the control column. This, combined with flap extension and reduced speed should permit easier manual trimming.
If other methods fail to relieve the elevator load and control column force, use the "roller coaster" technique. If nose-up trim is required, raise the nose well above the horizon with elevator control. Then slowly relax the control column pressure and manually trim nose-up. Allow the nose to drop below the horizon while trimming. Repeat this sequence until the airplane is trim.
Extract from the Boeing 737-200 Pilot Training Manual February 1982 page 04.80.31. Edited for brevity
Runaway and Manual Stabiliser - Recovery from Severe Out-of-Trim
"In an extreme nose-up out-of-trim condition, requiring almost full forward control column, decelerate, extend the flaps and/or reduce thrust to a minimum practical setting consistent with flight conditions until elevator control is established. Do not decrease airspeed below the minimum maneuvering speed for the flap configuration. A bank of 30 degrees or more will relieve some force on the control column. This, combined with flap extension and reduced speed should permit easier manual trimming.
If other methods fail to relieve the elevator load and control column force, use the "roller coaster" technique. If nose-up trim is required, raise the nose well above the horizon with elevator control. Then slowly relax the control column pressure and manually trim nose-up. Allow the nose to drop below the horizon while trimming. Repeat this sequence until the airplane is trim.
maybe neutralized with up with column electrical trim first than kill the 2 switches like jt043. It’s already proven
Join Date: Jan 2008
Location: farmm intersection, our ranch
Age: 57
Posts: 206
Likes: 0
Received 0 Likes
on
0 Posts
Gender Faculty Specialist
Join Date: Mar 2019
Location: Europe
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Mar 2012
Location: Arizona
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
VESBOT states:
You're mistaken, "climbing" (or, put more precisely) elevator/AOA control always controls speed. Of course, under the likely MCAS scenario discussed, they did not have AOA control and the airspeed was running away from them.
And thrust always controls vertical flight path, so if they reduced thrust they would have only hit the ground sooner. In a desperate fight for altitude, "piloting" would dictate maximum thrust.
If the above is true, when you are ready for take off, try this:
Pump the elevators up and down until you has reached VR, then when you reach VR, shove the throttles to maximum to rotate.
You're mistaken, "climbing" (or, put more precisely) elevator/AOA control always controls speed. Of course, under the likely MCAS scenario discussed, they did not have AOA control and the airspeed was running away from them.
And thrust always controls vertical flight path, so if they reduced thrust they would have only hit the ground sooner. In a desperate fight for altitude, "piloting" would dictate maximum thrust.
If the above is true, when you are ready for take off, try this:
Pump the elevators up and down until you has reached VR, then when you reach VR, shove the throttles to maximum to rotate.
I think you are getting confused with recovering from flight near stall with a nose up attitude and high AOA. In that specific situation slamming the power to max will cause the nose to pitch up further because the stabilator has far less control authority.
Join Date: Sep 2016
Location: USA
Posts: 803
Likes: 0
Received 0 Likes
on
0 Posts
VESBOT states:
You're mistaken, "climbing" (or, put more precisely) elevator/AOA control always controls speed. Of course, under the likely MCAS scenario discussed, they did not have AOA control and the airspeed was running away from them.
And thrust always controls vertical flight path, so if they reduced thrust they would have only hit the ground sooner. In a desperate fight for altitude, "piloting" would dictate maximum thrust.
If the above is true, when you are ready for take off, try this:
Pump the elevators up and down until you has reached VR, then when you reach VR, shove the throttles to maximum to rotate.
You're mistaken, "climbing" (or, put more precisely) elevator/AOA control always controls speed. Of course, under the likely MCAS scenario discussed, they did not have AOA control and the airspeed was running away from them.
And thrust always controls vertical flight path, so if they reduced thrust they would have only hit the ground sooner. In a desperate fight for altitude, "piloting" would dictate maximum thrust.
If the above is true, when you are ready for take off, try this:
Pump the elevators up and down until you has reached VR, then when you reach VR, shove the throttles to maximum to rotate.
Join Date: Jan 2015
Location: Banksville
Posts: 70
Likes: 0
Received 0 Likes
on
0 Posts
Does anyone know ETs procedure for Airspeed Disagree? Experiencing that error due to AoA vane failure, would they have simply gone for ex 80% N1, and then Flaps Up to keep bits from coming off?
At which point they’re soon rocketing along, MCAS kicks in, and they can’t climb?
At which point they’re soon rocketing along, MCAS kicks in, and they can’t climb?
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,350
Likes: 0
Received 0 Likes
on
0 Posts
Yes but reducing thrust on the 737 creates a large nose down moment (pitch/power couple) so as Vessbott stated they would have just hit the ground sooner.
My experience of this is unusual attitude recovery during manual reversing air tests. Reducing thrust, if you're already using everything you have to keep the nose up, WILL result in a further nose down moment and no reduction in speed. They'd have been better off sticking the speed brakes up.
And in fact Boeing DO publish this in the QRH.
My experience of this is unusual attitude recovery during manual reversing air tests. Reducing thrust, if you're already using everything you have to keep the nose up, WILL result in a further nose down moment and no reduction in speed. They'd have been better off sticking the speed brakes up.
And in fact Boeing DO publish this in the QRH.