Connect and get the inside scoop on Airline Companies

Welcome to Airline Pilot Forums - Connect and get the inside scoop on Airline Companies

If this is your first visit, be sure to check out the FAQ. Join our community today and start interacting with existing members. Registration is fast, simple and absolutely free.


User Tag List

Post Reply
 
Thread Tools Search this Thread
Old 09-16-2020, 07:52 AM   #1  
Gets Weekends Off
Thread Starter
 
docav8tor's Avatar
 
Joined APC: Apr 2019
Posts: 107
Default Boeing 737 MAX Investigation

Final Committee Report Materials

docav8tor is offline  
Old 10-12-2020, 03:57 AM   #2  
Line Holder
 
takingmessages's Avatar
 
Joined APC: Mar 2017
Posts: 83
Default Sully Says MAX Needs More Fixes

https://www.avweb.com/aviation-news/...ds-more-fixes/

Flight 1549 Capt. Chesley Sullenberger says he’ll fly on the recertified Boeing 737 MAX but he wants to see improvements to the aircraft and its ancestors for flaws laid bare in the investigation of the MAX flight control system. “People are going to fly on it and I will probably be one of them,” he told the Seattle Times. “I’m going to keep on pushing for future improvements to this airplane even if it flies in the meantime,” he said.


The FAA is likely weeks away from clearing the MAX for revenue service after Boeing spent the last year rewriting a major portion of the flight control software to change the way the Maneuvering Characteristics Augmentation System (MCAS) behaves. Bad data from single-source angle of attack indicators on a Lion Air MAX and an Ethiopian Airlines MAX started a catastrophic chain of events that led to both aircraft entering high-speed dives that killed a total of 346 people in late 2018 and early 2019. Sullenberger says the MCAS fix is fine but the process of achieving it showed the MAX and its predecessor, the NG series, need upgrades in other systems.

Part of the MCAS revision was making it require agreement from both angle of attack indicators. Sullenberger agrees with the European Aviation Safety Agency (EASA) that there should be a third AOA and not necessarily a conventional aerodynamic type. Boeing 787s have a digital AOA that calculates attitude based on various sensor inputs and it acts as a check on the other two so pilots know which of those is acting up. Boeing considered adding the digital AOA to the MAX but it was rejected because of the cost.

Sullenberger also says something must be done about the cacophony of alarms and flashing lights that assault pilots when something goes wrong with the MAX. He said the noise and resulting confusion in the Lion Air and Ethiopian cockpits likely played a role in the outcome as they tried to isolate the source of the problems. “It was clear to me how the accident crews could have run out of time and altitude,” he said. He said he also agrees with Transport Canada that there should be a switch to turn off the stick shaker when pilots are sure it was triggered erroneously. With the flaws now revealed, Sullenberger says the FAA and Boeing have a duty to address them and not just leave it at the MCAS fix. “I’m not going to say, ‘We’re done, good enough, move on,'” said Sullenberger.
takingmessages is offline  
Old 10-12-2020, 08:15 PM   #3  
Gets Mon-Sun Off
 
TransWorld's Avatar
 
Joined APC: Aug 2016
Position: Up Front
Posts: 2,428
Default

For something as critical as MCAS, I never could figure out why it was not mandatory to have both AOA sensors installed and both in agreement, called 2oo2 voting. If instruments don’t agree, kick it to the pilots to fly the plane. Give them the sensor disagreements and let skilled, experienced humans make the decision. Seems too obvious to me. Maybe Monday morning quarterbacking, but...
TransWorld is offline  
Old 10-12-2020, 10:33 PM   #4  
Gets Weekends Off
 
JamesNoBrakes's Avatar
 
Joined APC: Nov 2011
Position: Volleyball Player
Posts: 3,564
Default

Quote:
Originally Posted by takingmessages View Post
https://www.avweb.com/aviation-news/...ds-more-fixes/

Flight 1549 Capt. Chesley Sullenberger says he’ll fly on the recertified Boeing 737 MAX but he wants to see improvements to the aircraft and its ancestors for flaws laid bare in the investigation of the MAX flight control system. “People are going to fly on it and I will probably be one of them,” he told the Seattle Times. “I’m going to keep on pushing for future improvements to this airplane even if it flies in the meantime,” he said.


The FAA is likely weeks away from clearing the MAX for revenue service after Boeing spent the last year rewriting a major portion of the flight control software to change the way the Maneuvering Characteristics Augmentation System (MCAS) behaves. Bad data from single-source angle of attack indicators on a Lion Air MAX and an Ethiopian Airlines MAX started a catastrophic chain of events that led to both aircraft entering high-speed dives that killed a total of 346 people in late 2018 and early 2019. Sullenberger says the MCAS fix is fine but the process of achieving it showed the MAX and its predecessor, the NG series, need upgrades in other systems.

Part of the MCAS revision was making it require agreement from both angle of attack indicators. Sullenberger agrees with the European Aviation Safety Agency (EASA) that there should be a third AOA and not necessarily a conventional aerodynamic type. Boeing 787s have a digital AOA that calculates attitude based on various sensor inputs and it acts as a check on the other two so pilots know which of those is acting up. Boeing considered adding the digital AOA to the MAX but it was rejected because of the cost.

Sullenberger also says something must be done about the cacophony of alarms and flashing lights that assault pilots when something goes wrong with the MAX. He said the noise and resulting confusion in the Lion Air and Ethiopian cockpits likely played a role in the outcome as they tried to isolate the source of the problems. “It was clear to me how the accident crews could have run out of time and altitude,” he said. He said he also agrees with Transport Canada that there should be a switch to turn off the stick shaker when pilots are sure it was triggered erroneously. With the flaws now revealed, Sullenberger says the FAA and Boeing have a duty to address them and not just leave it at the MCAS fix. “I’m not going to say, ‘We’re done, good enough, move on,'” said Sullenberger.
There was a fascinating article I read last year about using an artificial airspeed indicator to provide a backup, similar to the artificial AOA. It found that the margin of error estimating airspeed from GPS/FMS speed after having input the winds-aloft data was very small, I don't remember if it was 5%, but 5-10% and generally enough to safely fly the airplane in any condition. This was more directed towards the air-france accident and a few others, where people thought they were stalling when they started getting erroneous airspeed readings, but same general idea. The real interesting part was the error was not nearly as big as one might think.
JamesNoBrakes is offline  
Old 10-13-2020, 08:58 AM   #5  
Gets Weekends Off
 
PerfInit's Avatar
 
Joined APC: Oct 2008
Position: JAFO- First Observer
Posts: 902
Default

From what I read in the report, The OEM floated the idea of synthetic airspeed for the Max but realized quickly that due to “new & novel” language in Part 25 Cert rules, this would delay the cert and jeopardize their plan of “minimal training differences (Level B) between NG and Max.

The ADIRUs provide HDG/Groundspeed display to the ISDU on the overhead. Not stated in the NNC for Unreliable Airspeed explicitly, but this could be useful information if the pilots know where to find it and how it is determined.
PerfInit is offline  
Old 10-13-2020, 09:22 AM   #6  
Prime Minister/Moderator
 
rickair7777's Avatar
 
Joined APC: Jan 2006
Position: Engines Turn Or People Swim
Posts: 27,338
Default

Quote:
Originally Posted by PerfInit View Post
From what I read in the report, The OEM floated the idea of synthetic airspeed for the Max but realized quickly that due to “new & novel” language in Part 25 Cert rules, this would delay the cert and jeopardize their plan of “minimal training differences (Level B) between NG and Max.
Lessons learned the hard way drive stringent regulation and oversight bureaucracy in aviation... the flip side of that is that it naturally slows technical progress. The only reason we're getting new alternatives to our ASEL motors designed in the 1940's is because of leaded gas and environmental pressure.

Quote:
Originally Posted by PerfInit View Post
The ADIRUs provide HDG/Groundspeed display to the ISDU on the overhead. Not stated in the NNC for Unreliable Airspeed explicitly, but this could be useful information if the pilots know where to find it and how it is determined.
Could be useful for triage on instrument disagreements... if you have the presence of mind to use it in the heat of battle. I'd hate to have to fly the plane by reference to the overhead panel though. Unless you had a jumpseater who could call out the parameters for you.
rickair7777 is offline  
Old 10-13-2020, 03:30 PM   #7  
Gets Weekends Off
 
firefighterplt's Avatar
 
Joined APC: Mar 2020
Posts: 296
Default

Hornet runs dual probes and a third INS-derived AOA. If a probe mismatch occurs, you get a warning, and can manually select the good probe by comparing them to the INS-derived AOA (which is pretty tight).

I’m sure the software is very different, but the logic is already there...in another Boeing product, nonetheless.......
firefighterplt is offline  
 
 
 

 
Post Reply
 



Thread Tools Search this Thread
Search this Thread:

Advanced Search


Related Topics
Thread Thread Starter Forum Replies Last Post
Indonesia to Fault 737 MAX Design... docav8tor Safety 10 09-24-2019 01:20 PM
The Roots of Boeing’s 737 Max Crisis... docav8tor Safety 6 08-02-2019 08:58 AM
The Boeing 737 Max Crisis Is a Leadership... docav8tor Safety 0 07-20-2019 09:00 AM
Boeing 737 Max's Autopilot Has Problem docav8tor Safety 7 07-10-2019 11:20 AM
Need help from Pinnacle and Skywest pilots... essw Regional 7 06-27-2009 01:00 PM


All times are GMT -8. The time now is 04:59 PM.