Ethiopian airliner down in Africa
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The 787 was grounded for three months in 2013. I assume they will be checked at the same time as the software patch and AoA sensor re-jig is done.
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If I remember AF447 correctly it was all speculation as there was no data until over a year later when the recorders were recovered. At that time, if my memory serves me right, data showed the flight crew member in the right seat was commanding pitch up with his joystick while the pilot in the left seat was either neutral or pitch down. Basic flaw of joysticks on 2 crew cockpits in that they do not provide input by feel between flight crew. Thales sensors were speculation due to failure history.
I keep looking here to see if there is data confirming why Ethiopian crashed similar to the data on Lion Air. Have I missed it? In the case of the Lion Air there was the history of the previous flight where the pilot experienced the same sensor malfunction yet flew to destination. Ethoiopian says the previous flight was normal with no write-ups. It reminds me so much of the AA DC-10 in Chicago where the action was to shoot first and ask questions later with the evidence of what happened lying on the runway. Yes, the DC-10 had many faults resulting from rushing into production but engines falling off wings was not one of them. Engines falling off wings causing the slats to retract was a design flaw.
Now the media is interviewing MAX pilots who say they have spent their time as MAX pilots terrified of their life due to control problems. How come they did not say this before? And we have Donald Trump saying airplanes today are too complex for pilots to fly. It just keeps getting worse and worse.
I keep looking here to see if there is data confirming why Ethiopian crashed similar to the data on Lion Air. Have I missed it? In the case of the Lion Air there was the history of the previous flight where the pilot experienced the same sensor malfunction yet flew to destination. Ethoiopian says the previous flight was normal with no write-ups. It reminds me so much of the AA DC-10 in Chicago where the action was to shoot first and ask questions later with the evidence of what happened lying on the runway. Yes, the DC-10 had many faults resulting from rushing into production but engines falling off wings was not one of them. Engines falling off wings causing the slats to retract was a design flaw.
Now the media is interviewing MAX pilots who say they have spent their time as MAX pilots terrified of their life due to control problems. How come they did not say this before? And we have Donald Trump saying airplanes today are too complex for pilots to fly. It just keeps getting worse and worse.
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Aireon FAA
It seems Aireon had better data than FR24 and this led to the FAA decision. This is surprising because Aireon update rate is said to be once per minute.
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Quote:
American air safety experts are trying to persuade their Ethiopian counterparts not to send the flight data to crash investigators in London, The Wall Street Journal reported. Instead, they want it examined by the National Transportation Safety Board in the United States.
American air safety experts are trying to persuade their Ethiopian counterparts not to send the flight data to crash investigators in London, The Wall Street Journal reported. Instead, they want it examined by the National Transportation Safety Board in the United States.
That's bordering on all-out National panic of losing their big aircraft manufacturer. Wouldn't have expected the Panic going that far and reaching formerly largely independent Organisations (NTSB) in the US.
So far I had not really been concerned the US would go from Template Democracy to Bananas Republic in just one Presidency. Seeing this I start scratching my head...
Well my dear fellow Ppruners,
Perhaps this is the day that we, as an aviation resource site, have caused the global grounding of an aircraft type. I believe that the discussion that was/is going on here, and the raised concerns by some very knowledgeable experts (between some questionable commenters) has provided the world the leverage that was necessary.
Sometimes it is better to be prudent. Maybe this is it.
I am looking forward to the FAA “new evidence” that they mentioned.
Perhaps this is the day that we, as an aviation resource site, have caused the global grounding of an aircraft type. I believe that the discussion that was/is going on here, and the raised concerns by some very knowledgeable experts (between some questionable commenters) has provided the world the leverage that was necessary.
Sometimes it is better to be prudent. Maybe this is it.
I am looking forward to the FAA “new evidence” that they mentioned.
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Now Boeing have joined the party
https://www.bbc.co.uk/news/business-47562727
https://www.bbc.co.uk/news/business-47562727
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FCeng84FCeng84 , 12th Mar 2019 22:26
Quote:
Originally Posted by hans brinker
You would be making things worse by adding power. To get out of a high AOA, you lower the nose before adding power.....
Hans - your patience is amazing. You are correct about the relationship between 737MAX engines and need for MCAS. It has nothing to do with the thrust pitching moment!!!
There is a cert requirement that as AOA increases, the nose up pilot command required must not decrease. This is demonstrated at fixed thrust levels so there is no change in thrust pitching moment. The 737MAX issue here that gives rise to the need for MCAS is that as AOA increases the lift provided by the engine cowling that is so large and mounted so far forward of the wing causes a nose up pitching moment that results is a decrease in the column pull needed to maintain a steady positive AOA rate. That characteristic is not compliant with the requirements. MCAS comes active during this maneuver putting in nose down stabilizer that must be countered by the column. The net effect of engine cowling lift and MCAS nose down stabilizer as AOA increases is that the column needed to complete the maneuver does not decrease part way through the range of AOA for which characteristics must be demonstrated. 737MAX without MCAS fails the cert demo. 737MAX with MCAS passes the cert demo.
Quote:
Originally Posted by hans brinker
You would be making things worse by adding power. To get out of a high AOA, you lower the nose before adding power.....
Hans - your patience is amazing. You are correct about the relationship between 737MAX engines and need for MCAS. It has nothing to do with the thrust pitching moment!!!
There is a cert requirement that as AOA increases, the nose up pilot command required must not decrease. This is demonstrated at fixed thrust levels so there is no change in thrust pitching moment. The 737MAX issue here that gives rise to the need for MCAS is that as AOA increases the lift provided by the engine cowling that is so large and mounted so far forward of the wing causes a nose up pitching moment that results is a decrease in the column pull needed to maintain a steady positive AOA rate. That characteristic is not compliant with the requirements. MCAS comes active during this maneuver putting in nose down stabilizer that must be countered by the column. The net effect of engine cowling lift and MCAS nose down stabilizer as AOA increases is that the column needed to complete the maneuver does not decrease part way through the range of AOA for which characteristics must be demonstrated. 737MAX without MCAS fails the cert demo. 737MAX with MCAS passes the cert demo.
1. MCAS activated by errant AoA vane data. (This same data may also lead to warnings such as stall etc.)
2. So, by the time you run through checklist, source the problem and stop the MCAS from further inputs by flicking the Stab trim cutout, the stab is already at X° nose down.
3. At relatively low speed you're able to manage this by pulling back on the yoke, and the now fixed stab angle may even go unnoticed and forgotten about for a while
4. Additional engine power may already have been applied, but, if not, you do so now as you need some height, especially with advancing terrain and the loss of altitude that you'd suffered.
5. The effects of the engine cowling on aerodynamics, as stated in the comment above, helps lift, as does the thrust moment created by the engines
6. You think you have the problem somewhat under control compared to the situation you were in a minute ago. You've now been able to climb and seem to have relatively stable manual control.
7. Now you're at Y feet, (still with X° nose down stab trim) with an increased airspeed of Z, up until now has been controllable due to your elevator inputs being assisted by thrust moment and engine aerodynamics, but, at this new increased airspeed and increased altitude the yoke is becoming even more difficult to keep holding back. The stab is still in the same X° nose down it was when you switched the cut-outs, and up until now you mightn't have thought about it because you'd disabled it- in accordance with the checklist.
8. You think about returning and getting this back on the ground
9. Once you level off, or even before then, with that stab STILL at X° nose down (now with a much higher airspeed component) there's only one place you're going. Once this vertical direction change has momentum there's now no chance, no elevators in the world are going to help you.
Look at the memory item for stab runaway- i.e.- not told to manually wind back trim wheel, the instruction is to "grab and hold".
All this could be caused by one errant sensor? Madness that it was certified.
Last edited by positiverate20; 13th Mar 2019 at 22:20.
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Issued by whom?
<pedant mode> A number of PPRuNe posters and news outlets have said that Trump has issued an emergency order. Perhaps I'm not reading the right news, but I see only that Trump has said that "we" and "the FAA" will issue an emergency order, and I see that the FAA has said, "The FAA is ordering the temporary grounding of Boeing 737 MAX aircraft..." - no emergency order from the White House per se. </pedant mode>
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FAA chief says data aligns Ethiopia flight data to Lion Air accident
From CNN's Greg WallaceSpeaking with reporters on a conference call, acting FAA Administrator Daniel Elwell said the grounding of the 737 Max 8 and 9 will remain in effect pending new information including from the flight data recorder and voice recorder.
“Since this accident occurred we were resolute that we would not take action until we had data,” Elwell said.
“That data coalesced today.” Elwell said the new data was "added fidelity -- missing pieces that we did not have prior to today." It aligned the Ethiopian flight data to the Lion Air incident.
Elwell declined to guess how long the grounding would last but he said he hoped to keep it "as short as possible."
“I can’t and I don’t want to hazard a guess as to how long. My hope is that the FAA, the carriers, the manufacturer, that all parties will work very hard to make this grounding as short as possible so that these airplanes can get back up into the sky," he said.
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If one presumes the grounded aircraft will be towed to an unused corner of their respective airports rather than taking up valuable space on the apron, or at gates, would preventative preparations be made for an extended grounding? How long can the aircraft be grounded for in a "cold" state without requiring extensive checks and maintenance prior to returning to service?
Would the airports be levying a "storage charge"?
Would the airports be levying a "storage charge"?
From the Order:
