jeremyp
Illuminator
https://www.channelnewsasia.com/bus...n-request-safety-scrutiny-intensifies-4084281
Boeing withdraws request to self certify the Max 7.
I’m surprised that marketing and PR haven’t told them not to call it “Max” anything.
https://www.channelnewsasia.com/bus...n-request-safety-scrutiny-intensifies-4084281
Boeing withdraws request to self certify the Max 7.
I find some of the information in this article worrying
https://www.bbc.com/news/world-us-canada-67909417
Particularly this bit
"Alaska Airlines placed restrictions on the Boeing plane involved in a dramatic mid-air blowout after pressurisation warnings in the days before Friday's incident, investigators say.""An additional maintenance look" was requested but 'not completed' before the incident"
Really? That's all they did - had a "maintenance look" and placed restrictions!!?
I was an aircraft engineer in military aviation, I have never worked in the civil aircraft industry. However, I can't imagine that maintenance and safety procedures would be all that different from an engineering standpoint.
If we had pressurization warnings in a aircraft, this would absolutely be investigated with physical examinations and testing. In the example I know best, the Lockheed C-130 Hercules, every pressure door or openable/removable panel in the pressure hull would be checked for seal integrity - this would include the forward crew egress door, the two paratroop doors on either side of the rear fuselage and the cargo ramp and door...
[qimg]https://www.dropbox.com/scl/fi/7zj1aoyy5ta30n9dhgf60/C-130-FwdCrewEntryDoor.jpg?rlkey=iwm8atckcaig2pxxp5w2arn4f&raw=1[/qimg] [qimg]https://www.dropbox.com/scl/fi/g98tpt84rt2c16d2etnsl/C-130-ParatroopDoors.jpg?rlkey=t9deg2v71dmeq7sabolk8f2ig&raw=1[/qimg] [qimg]https://www.dropbox.com/scl/fi/jtra2s9pudtejuba04zpw/C-130-CargoRamp-Door.jpg?rlkey=w7gxtcmuucv1ip2txr1lx1ow7&raw=1[/qimg]
Also, any pressure panels such as the Doppler radar and radar altimeter radomes on the bottom of the aircraft would be checked for pressure leaks.
This procedure involves first an inspection of the seals, followed by a ground pressurization check. On the C-130 this means closing the aircraft up, shutting the outflow valves and starting up the GTC (in later models the APU) to begin pressuring the aircraft to a pre-set level. Then the ground crew works their way around the aircraft checking for leaks at the doors and panels mentioned above.
I struggle to imagine a scenario in civilian aviation where pressurization warnings would not be followed up with inspection and testing, but it seems all Alaska Airlines did was "have a look".
In my book, this is in no way good enough when you are dealing with the lives of the the public.
No. That's not all they did. The article says it had not been completed by the time of the "accident" flight. So they hadn't even done a "maintenance look".
Incidentally, would a ground pressurisation test have discovered the problem? If the door happened to be correctly seated when they did the test, it would have shown no problem. In fact, maybe the reason why they were treating the pressurisation warnings in such a relaxed way is because they had done ground pressurisation tests and found no issue and thus assumed it was a sensor fault.
Seems quite likely. On the basis that the plug door was seated in the correct place by gravity whilst on the ground it would not leak if pressurised. If there was no leak detected outside the plug there would have been no reason to pull the inner liner away to check the fixings. The last landing might well have been enough to reseat the door as far down as it was designed to go.
Incidentally, would a ground pressurisation test have discovered the problem? If the door happened to be correctly seated when they did the test, it would have shown no problem. In fact, maybe the reason why they were treating the pressurisation warnings in such a relaxed way is because they had done ground pressurisation tests and found no issue and thus assumed it was a sensor fault.
Nope! That is completely, wrong.
https://www.npr.org/2024/02/07/1229...ug-that-blew-off-a-boeing-737-max-9-ntbs-says
The NTSB appears to have determined that the four bolts required to ensure the exit blank is lifted up before being pushed out pretty much rips the rug out from under any notion that gravity was holding it in place. Without the bolts, there is no vertical movement of the exit blank required. The only things holding it in place were the 12 stop pads (6 pairs on either side).
A Commenter on this page who I can tell knows exactly what he is talking about, makes this very clear (my bolding for emphasis).
"It cannot be emphasized enough that the bolts do not do the work of holding the Exit Blank against pressure.
That is the job of 12 pads (6 on both the exit blank and the door frame.) When Pressure is applied inside, it pushes the exit door against those pads and those are what hold the door against pressure.
The Bolts are in two tracks (left and right) at the top and across the springs at the bottom (again two – its a more nuanced that that at the bottom but all 4 keep the door from moving upwards)
Upwards and then out moves the door off the pads and flimsy brackets hold it onto the hull of the aircraft. Those are simply to hold the door in place so the Exit Blank can be inspected or maint done. They serve no purpose for holding against pressure nor letting the door be moved into its maint position.
Once in the maint position the exit blank can stay there until returned to its normal position or removed if more in depth maint is needed on the exit blank (this also is a position a seal can be put around the plug/exist blanks)
Its is very possible that the 15,500 foot event could only occur in a band at lower attitudes (below 20k for instance). The more pressure on the pads the more friction and the exit blank may not move above say 20k.
But below X altitude with no bolts it can move and it did.
It was always clear there were not bolts in place as there was not tearing damage (though one bolt might have kept it form moving, no telling)
It ejected so cleanly it was clear there was nothing there.
It was possible they had “rattled” loose but that gets into impossible if the washers, nuts and cotter key wee installed at all on any one of them (and if one bolt was installed correctly its a certainty that all of them would have been as the mechanic would have been aware and the lack would catch his eye or not having 4 in hand would send red flags up)
It is my professional opinion as a retired aeronautical engineer, one who has not only worked on aircraft pressurization systems, but also supervised their repair, maintenance and testing, and given the fact there were no bolts in place, that a properly conducted ground pressurization test was very likely to have revealed severe leaks around that door, and depending on what altitude they pressurized to during the test, may have actually blown the exit blank out during the test. Doing a ground pressurization test is an SOP when the aircrew are repeatedly reporting pressurization alarms, and no sensor issues are found.
For this reason, I am confident no such test was done in this case.
And how is the plug to be opened for maintenance past the 12 stop pads without raising it up? Those pads are fixed on both door and fuselage.
I doubt the plug could be moved from it's correct position whilst pressurised due to the loads on the stop pads, which suggests to me that the door had already moved up to partially disengage the stop pads before pressurisation took place on the flight in question.
I can picture the plug moving up and down on it's hinges/tracks during unpressurised flght, and then seating correctly during the landing and subsequent taxi to the gate.
I agree that the four security pins were not in place, I am not convinced that tests were not carried out on the ground. If the door was moving up and down during unpressurised flight it is quite possible it was in the correct position on the ground and thus passed a pressurisation test.
Here is the thing though... everyone makes mistakes.
Oh sure, it has to be pushed up, but with the bolts not in place, a bump on landing, or even while taxiing could do that and there is no guarantee that the exit blank would come back down to its correct position. A misplaced exit blank would be almost impossible to spot during the the flight crew pre-flight inspection. It might not even be detected at all from the outside, and there is no way to detect it from the inside because it is covered up by the interior lining.
I agree
What unpressurized flight?
No part of a flight in a pressurized airliner is unpressurized. An airliner begins to pressurize from the moment the pilot pushes the engine levers to TOGA, and is still partially pressurized on the ground at touchdown.
From the Boeing 737 Flight Crew Operations Manual
- The cabin begins to pressurize on the ground at higher power settings. The controller modulates the outflow valve toward close, slightly pressurizing the cabin. This ground pressurization of the cabin makes the transition to pressurized flight more gradual for the passengers and crew, and also gives the system better response to ground effect pressure changes during takeoff.
- The descent mode is activated when the airplane descends 0.25 psi below the selected FLT ALT. The cabin begins a proportional descent to slightly below the selected LAND ALT. The controller programs the cabin to land slightly pressurized so that rapid changes in altitude during approach result in minimum cabin pressure changes.
While taxiing in, the controller drives the outflow valve slowly to the full open position depressurizing the cabin.
As I pointed out above, there is no "unpressurized flight"
The default position is that a GPC was not conducted unless there is evidence that it was.
Alaska Airlines said they did "another maintenance look but it was not completed" - "Maintenance look" is not a term I am familiar with, but is likely similar to the "Level One Inspections" we did in military aviation - a cursory inspection looking for obvious defects such as loose high-speed tape and frayed or missing rats rails on the trailing edges of control surfaces. It would include things such as pushing a "press-to-test" button to electrically check a sensor system was working.
"We did another maintenance look but it was not completed" is a euphemism for "we kicked the tyres and everything seemed fine - and we didn't even kick all of them".
A "maintenance look" is NOT a GPC. If you can provide evidence that a proper GPC was carried out, I will change my stance. Until then, I'll stick with what my professional experience tells me.
Ok, thank you for the details. So skip unpressurised flight and add unpressurised taxiing as per your first paragraph. Whilst there may be no guarantee that the plug might not return to the correct position during taxi to the gate there is no certainty it wouldn't do so.
There is a larger black section at the top of the plug on the outside, which I assume is the pressure seal. The black section appears to be there to allow the plug to be pushed up to open without hitting the fuselage opening. If the plug remained raised on the ground, even partially, the black patch at the top would be smaller and a corresponding black patch would appear at the bottom. That isn't to say the aircraft would be inspected on the outside, but the evidence would be there. You choose to deny the possibility of a pressure test having been done on the basis of your cynical view of the Alaska maintenance crews. I consider the evidence inconclusive either way.
Not related to Sir Humphrey Appleby by any chance?
I deny the possibility that a GPC was done because I know for a fact that it was not.
This is a CNN interview from three days ago, where Brianna Kielar is talking with David Soucie (author of "Why Planes Crash" and "Safer Skies") He has 45 years experience as an aircraft engineer, and is one of the world's leading experts on aviation mishaps and crashes.
If you won't accept this fact from me, perhaps you will accept it from him!
Kielar: That is a bombshell, as Pete said there, especially since it seemed before this door plug blew off, it was an airplane that was kind of giving some signs, right, with the pressurization issues that it had been experiencing on multiple occasions.
Soucie: Yeah, three times before this, they had pressurization indications, and the airplane was put on the ground. They inspected it, they checked it. They didn't go to the extent of doing a pressurization check on the ground, which typically isn't done. They'll do a couple of other things before they do that, but that's the one thing that I think is missing here. But this problem started long long before this actual door came out, that's for sure..... at Boeing.
You can watch the whole article here: https://www.youtube.com/watch?v=DSl3l1-UkHE
The interview with David Soucie starts here: https://youtu.be/DSl3l1-UkHE?t=224
Ok, I watched it. Did this CNN expert actually inspect the Alaska Airlines maintenance records?
Was he there at the time?
"Typically isn't done" isn't a statement of fact, it's a statement of opinion.
So, no, it still isn't a fact that they didn't pressurise it, but I accept that it is very unlikely they did, and even if they had, the door might well have been back in the correct position after taxi. ( in which case even an external examination would have shown no signs of movement)
They didn't need to, they talk to people with expertise as well as people involved in the investigation.
Did he need to be?
Do you disbelieve that the sun rises in the east unless you personally observe it rising.
Do you disbelieve that Neil Armstrong walked in the Moon in 1969 because you were not personally there to see it?
But "They didn't go to the extent of doing a pressurization check on the ground" is not a statement of opinion, it is a statement of fact! He is stating this in a way which clearly shows that he knows one was not done.
"Typically isn't done" is also a statement of fact... one that I can back up with personal experience. GPCs are not typically done unless there are repeated pressurization issues that have not been resolved with other inspections and tests. I can promise you that as NCO i/c servicing, if the aircrew flying any of the C-130's I was responsible for, twice reported pressurization alarms, the very next thing I would do is order a GPC, and it would be a "no-fly" priority (which means, the plane don't fly until the GPC is done and passes!)
I completely disagree with you on this. I seems clear to me now that no matter what evidence you are presented with, you have decided that you are right and everyone else is wrong. But I will give it one last try.
Have you seen pictures of the exit blank and the hole in blew out from? Here let me help you with that...
[qimg]https://www.dropbox.com/scl/fi/1ks9j1jms08p117zfbcx0/737-ExitBlank3.jpeg?rlkey=4x92dsav25ixh21p1oinu8t3w&raw=1[/qimg]
[IMGw=800]https://www.dropbox.com/scl/fi/w7otbadpw47w35pkjxq5w/737-ExitBlank1.jpg[/IMGw]
[qimg]https://www.dropbox.com/scl/fi/wpps5nh84mvih43z52k01/737-ExitBlank2.png?rlkey=h82desxbnjygcfwqpy7ki7irp&raw=1[/qimg]
Look at the three photos above, and thinking about the issue of pressurization and the fact that the door blew out when the aircraft was pressurized, what do you notice about those three photographs?
In 2018, Ed Pierson decided that he could no longer work as a senior manager for Boeing’s 737 MAX program.
At the company’s production facility in Renton, Washington, he had watched as employee morale plummeted and oversight and assembly procedures faltered. He told his superiors but retired soon after. But then fatal MAX 8 crashes occurred in 2018 and 2019. He decided to speak up publicly and was then called to testify before Congress on the problems he says he saw up close.
Five years later, after a door plug blew off of a 737 MAX 9 in the middle of an Alaska Airlines flight last month, Pierson is again trying to sound the alarm. Regulators ultimately approved the plane to return to the air nearly two years after the 2019 crash, but Pierson still doesn’t trust the MAX line — the modernized, more fuel-efficient version of Boeing’s predecessor planes.
“The Boeing Company is capable of building quality airplanes,” says Pierson, now the executive director for the nonprofit Foundation for Aviation Safety. “The problem is leadership, or lack thereof, and the pressure to get airplanes out the door is greater than doing the job right.”
The plot thickens...
Boeing whistleblower found dead in US
What plot? Thickens how?
Boeing stating that the guy died of a self-inflicted wound is really nasty.
I was appalled when I heard that announced on the news here, and more appalled now that I see the article attributes that comment to Boeing.
Boeing stating that the guy died of a self-inflicted wound is really nasty.
I was appalled when I heard that announced on the news here, and more appalled now that I see the article attributes that comment to Boeing.
Boeing said it was saddened to hear of Mr Barnett's passing. The Charleston County coroner confirmed his death to the BBC on Monday.
It said the 62-year-old had died from a "self-inflicted" wound on 9 March and police were investigating.
I'm still appalled that the 'self inflicted wound' stuff was announced at all.
Another oopsie with 737-800
https://abc7news.com/united-flight-missing-panel-sfo-medford-oregon/14529741/
"United plane apparently loses external panel mid-flight after taking off from SFO, officials say
A United Airlines flight that took off from San Francisco International Airport Friday morning landed in Oregon with a missing external panel, according to officials.
United Flight 433 left San Francisco at 10:20 a.m. and landed at Rogue Valley International-Medford Airport in Medford shortly before noon, according to FlightAware. The airport's director, Amber Judd, said the plane landed safely without incident and the external panel was discovered missing during a post-flight inspection."
If its Boeing, I ain't going!!
Another oopsie with 737-800
https://abc7news.com/united-flight-missing-panel-sfo-medford-oregon/14529741/
"United plane apparently loses external panel mid-flight after taking off from SFO, officials say
A United Airlines flight that took off from San Francisco International Airport Friday morning landed in Oregon with a missing external panel, according to officials.
United Flight 433 left San Francisco at 10:20 a.m. and landed at Rogue Valley International-Medford Airport in Medford shortly before noon, according to FlightAware. The airport's director, Amber Judd, said the plane landed safely without incident and the external panel was discovered missing during a post-flight inspection."
If its Boeing, I ain't going!!
I'm still trying to figure out how much of this is quality control issues from the manufacturer, and how much of this is airlines cutting corners on routine maintenance.
The door plug incident is pretty clearly a manufacturer issue. A lot of these others seem like they're happening to parts of planes that the airline is responsible for maintaining.
As someone who used to maintain aircraft for the Navy, a missing panel sounds likely to be a maintenance issue rather than a manufacturing issue.
However, I can't say conclusively.
The retaining bolts for the plug were removed by the manufacturer so they could take the door off to fix an unrelated issue, but they weren't replaced afterwards. That is conclusively a manufacturing issue.
Fixing an issue is maintenance not manufacturing. Maintenance involves more than just changing the oil.
You understand that the issue jeremyp is talking about happened during the manufacture of the aircraft concerned, right?
It was carried out on the production line, by the same workers actually manufacturing the fuselages, propulsion systems and wing systems on the line at Spirit Aerosystems, and the work was signed off by the same Boeing supervisors that sign off all the steps and tasks during manufacture.
You might want to split hairs and call this actual, specific task "maintenance" on a technicality, but this happened at the factory where these aircraft are manufactured. The FAA would not be impressed by your hair-splitting.
The retaining bolts for the plug were removed by the manufacturer so they could take the door off to fix an unrelated issue, but they weren't replaced afterwards. That is conclusively a manufacturing issue.
March 15, 2024
Commercial Aviation / Medford, Oregon
United Airlines Flight 433 landed safely at Medford Airport in Oregon around 11:30 a.m. local time on Friday, March 15. A post landing airline inspection revealed a missing panel. The Boeing 737 departed from San Francisco International Airport. The FAA will investigate. Please contact the airline for more information.
Fixing an issue is maintenance not manufacturing. Maintenance involves more than just changing the oil.
If you want to blame it onBoeingmanufacturing, discuss why the bolts were needed at all and/or whether a more failsafe system could have been devised.
Are we talking about the same incident? United Flight 433? Was it a panel or a door?
https://web.archive.org/web/20240321131047/https:/www.faa.gov/newsroom/statements
Well, if we are splitting hairs, maintenance is "the process of preserving the condition of something". In this case, they were not preserving any kind of condition, they were fixing a manufacturing fault. That is part of the manufacturing process, and more importantly, it was done by the manufacturer, not the customer, which is what really counts here.Yes, I will split the hairs, and I don't give a stuff what the FAA think. Taking the plane to bits again to fix a problem is maintenance.
Whatever the cause, the plane was being manufactured by Boeing and Spirit was Boeing's subcontractor. The buck stops with Boeing.As to being signed off by Boeing staff, I thought the problem was that the actual workers were Spirit staff working at Boeing and there was no actual sign off of refitting the bolts since the quality systems were incompatible.
And I see you don't feel there should be any criticism of the design? No wondering if putting springs under the hinges was perhaps a mistake since the absence of the bolts allowed the springs to help the door upwards? No? okay then, it was just perfect as it was...