Ethiopian 737 MAX 8 crash
06-26-2019, 07:52 PM
#832
In a land of unicorns
Joined APC: Apr 2014
Position: Whale FO
Posts: 6,470
Originally Posted by ShyGuy
https://www.cnn.com/2019/06/26/polit...law/index.html
New flaw discovered with the MAX, a failure of the microprocessor.
When testing the potential failure of the microprocessor in the simulators, "it was difficult for the test pilots to recover in a matter of seconds," one of the sources said. "And if you can't recover in a matter of seconds, that's an unreasonable risk."
Why can't test pilots recover using the stab trim runaway procedure in a matter of seconds?
New flaw discovered with the MAX, a failure of the microprocessor.
When testing the potential failure of the microprocessor in the simulators, "it was difficult for the test pilots to recover in a matter of seconds," one of the sources said. "And if you can't recover in a matter of seconds, that's an unreasonable risk."
Why can't test pilots recover using the stab trim runaway procedure in a matter of seconds?
06-26-2019, 09:56 PM
#833
Gets Weekends Off
Joined APC: Dec 2005
Posts: 8,898
Originally Posted by dera
Ask JohnBurke. He could recover it in microseconds.
“Did you read the article?”
“You have a reading comprehension problem.”
“Stay focused.”
“You’re irrelevant.”
-John Burke trademarks
06-27-2019, 04:37 AM
#834
Gets Weekends Off
Joined APC: Mar 2014
Posts: 281
"While the issue didn’t involve the Maneuvering Characteristics Augmentation System linked to the two accidents since October that killed 346 people, it could produce an uncommanded dive similar to what occurred in the crashes, according to one person, who wasn’t authorized to speak about the matter."-Bloomberg
Curious. They effectively wired in a short to the stabilizer jackscrew actuator under some conditions?
Curious. They effectively wired in a short to the stabilizer jackscrew actuator under some conditions?
06-27-2019, 09:05 AM
#835
Prime Minister/Moderator
Joined APC: Jan 2006
Position: Engines Turn Or People Swim
Posts: 39,293
Originally Posted by F4E Mx
"While the issue didn’t involve the Maneuvering Characteristics Augmentation System linked to the two accidents since October that killed 346 people, it could produce an uncommanded dive similar to what occurred in the crashes, according to one person, who wasn’t authorized to speak about the matter."-Bloomberg
Curious. They effectively wired in a short to the stabilizer jackscrew actuator under some conditions?
Curious. They effectively wired in a short to the stabilizer jackscrew actuator under some conditions?
06-27-2019, 05:40 PM
#836
Disinterested Third Party
Joined APC: Jun 2012
Posts: 6,026
Originally Posted by F4E Mx
"While the issue didn’t involve the Maneuvering Characteristics Augmentation System linked to the two accidents since October that killed 346 people, it could produce an uncommanded dive similar to what occurred in the crashes, according to one person, who wasn’t authorized to speak about the matter."-Bloomberg
Curious. They effectively wired in a short to the stabilizer jackscrew actuator under some conditions?
Curious. They effectively wired in a short to the stabilizer jackscrew actuator under some conditions?
The latest syndicated article is deeply flawed with considerable incorrect information, references to old information with bad reporting, and melodrama.
06-27-2019, 11:07 PM
#837
Gets Weekends Off
Joined APC: Dec 2005
Posts: 8,898
Originally Posted by JohnBurke
No.
The latest syndicated article is deeply flawed with considerable incorrect information, references to old information with bad reporting, and melodrama.
The latest syndicated article is deeply flawed with considerable incorrect information, references to old information with bad reporting, and melodrama.
What basis are you making these statements on?
The article said:
“In simulator tests, government pilots discovered that a microprocessor failure could push the nose of the plane toward the ground. It is not known whether the microprocessor played a role in either crash.
When testing the potential failure of the microprocessor in the simulators, "it was difficult for the test pilots to recover in a matter of seconds," one of the sources said. "And if you can't recover in a matter of seconds, that's an unreasonable risk."
The sources say Boeing engineers are trying to determine if the microprocessor issue can be fixed by reprogramming software or if replacing the physical microprocessors on each 737 Max aircraft may be required.“
So what’s the incorrect information? What’s the deeply flawed info? And melodrama, it’s CNN so what do you expect.
06-28-2019, 01:12 AM
#839
Line Holder
Joined APC: Mar 2019
Posts: 53
Originally Posted by JohnBurke
The captain side indication was inaccurate, but airspeed was available on board, and in the event of no airspeed, every aircraft has a pitch and power schedule that begins with memory items and contains a list of power settings and pitch attitudes, along with aircraft configurations against a schedule of aircraft weight, to establish the correct airspeed for a particular phase of flight.
There was no excuse to accelerate out of the certification envelope and it's airmanship 101 to know that trim is for a particular airspeed, power setting, and configuration. If the aircraft is out of trim, particularly with a runaway trim, accelerating to a higher speed will create greater control forces (unless by dumb luck one accelerates to match airspeed to the newly trimmed state).
By allowing airspeed to increase, the nature of the out of trim condition was made worse. Much, much worse. Unlike a Cessna with a small tab to provide pitch trim, the 737 moves the entire horizontal stabilizer. An increase in speed will make the out of trim condition worse, and make the aircraft harder to fly; an increase to the maximum design speed will make it considerably worse and accelerating beyond the operating limits of the airplane (a place one should go under no circumstance) made it impossible. This was entirely within the control of the crew.
There was no excuse to accelerate out of the certification envelope and it's airmanship 101 to know that trim is for a particular airspeed, power setting, and configuration. If the aircraft is out of trim, particularly with a runaway trim, accelerating to a higher speed will create greater control forces (unless by dumb luck one accelerates to match airspeed to the newly trimmed state).
By allowing airspeed to increase, the nature of the out of trim condition was made worse. Much, much worse. Unlike a Cessna with a small tab to provide pitch trim, the 737 moves the entire horizontal stabilizer. An increase in speed will make the out of trim condition worse, and make the aircraft harder to fly; an increase to the maximum design speed will make it considerably worse and accelerating beyond the operating limits of the airplane (a place one should go under no circumstance) made it impossible. This was entirely within the control of the crew.
I see. Thank you for explaining that. Really interesting to read both arguments in this entire fiasco. I feel that the public will have a hard time accepting pilot error played a role when it happened twice in such a short time. What I don’t understand is how a faulty sensor crashes a plane. I don’t believe it does. But the media is saying otherwise. After I read about the Airbus in 2008 that had 3 AoA sensors. Had two fail which ended up rejecting the 3rd. In the end I read pilots were still at fault in the accident. I think the same outcome will happen in these, but won’t change much seeing how much emotion is being brought into the entire thing.
Thread
Thread Starter
Forum
Replies
Last Post
