Boeing 737 Max is safe to fly again, Europe’s aviation regulator says

[Guest]

10 hours ago, daydreamer said:

There are two sensors.  They are located on the outside of the cockpit, below the pilot side windows.  All large aircraft have these.  What was missing from the Indonesian and Ethiopian 737 Max aircraft were the angle of attack indicator (not sensor) and the disagree alert to alert the pilot if the two sensors do not match. 

That may also be missing, but to have a MCAS system that automatically compares the 2 sensors and disables MCAS, with a warning would be better than relying on the pilot to spot the problem and switch it off.     In principle, we should try to reduce the risk of human error.    

Better still would be to have a third source of angle of attack data, either from another similar sensor, or calculated from other information, then just flag up a sensor error and keep MCAS running as long as there are still 2 independent sources of data. 

Besides, from what I have seen in a documentary, they don't just switch have to switch MCAS off, but have to switch off electrical actuation of the pitch control.  The manual system relies on pulleys and according to 1 simulation, the pilot would have as little as 4 seconds to respond before the aero loading becomes too high.  

There is nothing fundamentally wrong with using software to improve control.  Despite this high profile failure, software on planes has been a huge net contributor to safety.   They just need to engineer the software properly, following established processes.     

Boeing failed to do that

Then they inexplicably tried to cover it up, even when anyone who understood the system must have understood it was a very plausible cause of the first crash. 

[reader]

On 10/17/2020 at 4:00 AM, 10tazione said:

Can those changes easily be applied to all the existing 737 Max? Is it only a software upgrade? Does anyone know?

Boeing believes that the changes can make existing MAX equipment safe to fly. Euro authorities appear to agree and it's not unlikely that the FAA (US) will follow suit before the end of the year.

From National Public Radio (30 Sept.)

The head of the Federal Aviation Administration conducted his own test flight of a Boeing 737 Max Wednesday, and he's giving it a positive review, as the regulatory agency gets closer to allowing the troubled jet to return to commercial passenger service more than 18 months after it was grounded.

FAA Administrator Steve Dickson, a former Delta Air Lines pilot, sat at the controls of a 737 Max and flew it through a number of different scenarios to test how the plane handled in crisis situations and to evaluate Boeing's revisions to the flight control system.

"I completed a number of test profiles today to examine the functionality of the aircraft and I liked what I saw, so it responded well," Dickson told reporters in a news conference after the flight. "I did two landings and also some air work maneuvers over about a two hour period... and I felt prepared. I think most importantly, I felt that the training prepared me to be very comfortable."

In the days leading up to his test flight, Dickson says he completed new pilot training procedures and a trial run in a 737 Max simulator.

The FAA administrator's test flight was a significant step in the agency's review of design and software changes made by Boeing to the flight control system after the crashes, as the regulatory agency works to re-certify the 737 Max and return the plane — long a mainstay of medium-haul routes — to passenger service.

But Dickson says his agency's technical and test flight data reviews are still ongoing and the re-certification process cannot and will not be rushed.

"We are not to the point yet where we have completed the process," Dickson said. "We're in the home stretch but that doesn't mean that we're going to take shortcuts to get it done by a certain date."

"The FAA and I in particular will not approve the plane for a return to passenger service until I'm satisfied that we've adequately addressed all of the known safety issues that played a role in the tragic loss of 346 lives aboard Lion Air flight 610 and Ethiopian Airlines flight 302."

But some family members of those killed call the test flight "a PR stunt" and "a gimmick." They're calling on the FAA and Boeing to release the technical descriptions and test data they are using to re-certify the plane, so it can be analyzed by outside aviation experts.

"Without that secret data, independent experts and the public cannot confirm whether the aircraft is safe," said Michael Stumo, whose 24-year old daughter Samya Rose Stumo, was among those who died in the Ethiopian 737 MAX crash.

But Dickson on Wednesday insisted "This is not a publicity stunt."

"This is simply the fulfillment of a commitment, a promise I made within my first few weeks at the FAA," he told reporters.

In response to the call to share data from the FAA's analysis and review of the 737 Max, Dickson said: "I think we have been transparent to an unprecedented degree... we are providing everything we can within the law," but he added that "much of the data that I believe is being asked for is proprietary in nature."

Since taking the helm of the FAA last fall, Dickson has said repeatedly that he was "not going to sign off" on the 737 Max "until I fly it myself and am satisfied I would put my own family on it without a second thought."

There are indications the 737 Max could be re-certified by the FAA sometime in late October or November, putting it on track to return to service before the end of the year or in early 2021.

[PeterRS]

Was reading a website today which provided information on one of the workhorses of aviation in the UK some decades ago. The BAC 1-11 had four AOA sensors! The revamped Max will still only have two.

There was also another interesting Seattle Times article last week where Captain Chesley Sullenberger (the "miracle on the Hudson" captain) states he is not satisfied with the changes being made by Boeing and the FAA. The main change he seeks is a third AOA indicator. This is included of Boeing's 787 Dreamliners but was rejected and is still rejected on the Max on grounds of cost. The article is here -

https://www.seattletimes.com/business/boeing-aerospace/celebrated-pilot-sully-urges-further-updates-to-boeings-737-max-and-to-older-737s/?utm_source=marketingcloud&utm_medium=email&utm_campaign=TSA_101020032254+'Capt.+Sully'+says+he's+not+satisfied+with+Boeing+737+MAX+yet_10_9_2020&utm_term=Registered User

In an exclusive interview, the celebrated pilot said that even if the FAA ungrounds the jet next month as expected, additional modifications are needed as soon as possible to improve the plane’s crew alerting system and add a third check on the jet’s angle of attack data.

“I’m not going to say, ‘We’re done, good enough, move on,'” said Sullenberger. 

“People are going to fly on it and I will probably be one of them,” he added. “The updated MAX will probably be as safe as the (previous model) 737 NG when they are done with it. But it’s not as good as it should be.”

Dennis Tajer, spokesman for the Allied Pilots Association (APA), the union representing American Airlines pilots, said he’s with Sullenberger.

Though the specific flight control software — the Maneuvering Characteristics Augmentation System (MCAS) — that brought down the jets in two fatal crashes is now fixed, Tajer said, the investigations into the crashes “have exposed other areas we can do better on that airplane” and also on the 737 NG.

“We cannot lose this opportunity to address something that needs to be enhanced,” Tajer said. 

With Boeing financially strapped, the cost of what they propose could be a major barrier — not least because the safety issues raised apply not just to the MAX but equally to older versions of the 737 currently flying, like the 737 NG.

But Sullenberger says these improvements will make 737s safer — both the MAX and the older models — and shouldn’t be shelved due to cost.

“Is that really something we are comfortable saying out loud to everybody who boards an airplane?” he said. “I just don’t think that’s defensible. In safety-critical domains, ‘just good enough’ isn’t.”

[Re the AOA sensors, Sully makes the point that] if one of two sensors is faulty, the computers won’t know which is correct.

The likely solution is not a third angle of attack vane on the jet’s exterior, but an indirect, “synthetic” software calculation of the angle of attack based on parameters such as the aircraft’s weight, speed, inertial position and GPS signal.

Boeing’s newest jet, the 787, has such a check on the reliability of its air data sensors called Synthetic Airspeed, a system Boeing rejected for the MAX on cost grounds.

[Guest]

15 minutes ago, PeterRS said:

In an exclusive interview, the celebrated pilot said that even if the FAA ungrounds the jet next month as expected, additional modifications are needed as soon as possible to improve the plane’s crew alerting system and add a third check on the jet’s angle of attack data.

I also favour a third source of data for this system, for reasons outlined in my previous post.   

Mind you, comparison with earlier aircraft which had 4 sensors is a little simplistic.   On a similar theme, the Boeing 747 launched in the 1960s had 4 engines, as engine reliability was not so good back in those days.    Now 787s have 2 engines, due to much better engine reliability.  

Whilst I expect a 2020 787 with 2 engines is more reliable than a 1970 787 with 4 engines, of course I feel slightly better seeing 4 engines on the plane.   Also, flying from London to Thailand, there are all sorts of countries where I really wouldn't want to make a forced landing in case of an engine failure on a twin engine plane.   Top of the list is Afghanistan.

Incidentally, Boeing were in some financial difficulty during the 747 development and were under some pressure to make the first flight, despite problems with the engines.  The first fight took place with a load of 12v batteries available to run back up hydraulics, just in case all 4 engines failed.  

Boeing were also unhappy with the rate of progress being made to fix the engine problems.    So Boeing took the boss of Pratt & Whitney for a flight, opened one engine to max throttle & blew it up in the air.    Then the pilot started increasing the load on a second engine, at which point, apparently commitments were made to get the issue fixed  quickly.  A fix was found shortly afterwards.

[PeterRS]

10 hours ago, z909 said:

Mind you, comparison with earlier aircraft which had 4 sensors is a little simplistic.   On a similar theme, the Boeing 747 launched in the 1960s had 4 engines, as engine reliability was not so good back in those days.    Now 787s have 2 engines, due to much better engine reliability. 

Tou are certainly correct about engine reliability and there was little point my bringing up the comparison. At least the early 747s did not self combust due to faulty battery protection as happened to some of the early 787s and required that entire fleet to be grounded  

[PeterRS]

Seems the Boeing 737 Max just cannot stay out of the nes. The BBC website has an article today with two respected airline experts claiming it is "too early" for the aircraft to be cleared to fly again.

Ed Pierson worked on the aircraft production for four years. He gave evidence against Boeing at the Congressional hearings. During those years he claims the factory in Renton outside Seattle was in a "chaotic" and "dysfunctional" state. He believes the not all the fault issues have been addressed in clearing the aircraft to fly again.

His concerns are backed up by Captain Chesley Sullenberger (the Miracle on the Hudson pilot). He believes the Max modifications do not go far enough. In particular he believes changes are needed to warning systems which were carried over from an earlier version of the 737 and "are not up to modern standards."

I have no idea who is correct. I don't even care. I will  just never fly a 737 Max. Period.

 

 

[vinapu]

who needs aircrafts those days anyways ?

[Guest]

31 minutes ago, PeterRS said:

I will  just never fly a 737 Max. Period.

I will just attempt to wait 5 years before flying one.

This will be more difficult than usual, since the short haul mass market is very roughly 50% 737s and 50% A320s.   The only way to be really sure of avoiding a max variant is by avoiding every airline that takes delivery of one or more max planes.