Airline Industry

[neeneko]

Loose bolts? That may be a serious quality control problem at Boeing. The video by GG above shows that all bolts ought to be secured by a pin against accidential loosening.

I wonder if there is a certain element of zipf's law here. On the line I am familiar with, their big thing is making sure there is no debris in the aircraft. Signs all over the place about checking for parts or tools or garbage, but not a single sign highlighting that you have to tighten every single bolt.

[bill_g]

I wonder if there is a certain element of zipf's law here. On the line I am familiar with, their big thing is making sure there is no debris in the aircraft. Signs all over the place about checking for parts or tools or garbage, but not a single sign highlighting that you have to tighten every single bolt.

I think the assumption is the tool's torque settings will achieve the correct tightness every time. ziiiiip-da-da-dat

[RTH10260]

Guide roller fittings on Alaska Max 9 door plug are fractured: NTSB

By Pilar Wolfsteller
9 January 2024

The US National Transportation Safety Board (NTSB) said that damage to a door plug which blew out of an in-flight Alaska Airlines Boeing 737 Max 9 last week includes fractured guide fittings that hold the plug in place.

In her third media briefing in as many days, NTSB chair Jennifer Homendy said on 8 January that while information is still being gathered on the cause of the blow-out, experts have been able to identify which parts of the aircraft’s door plug failed, after the piece was found in a yard in Portland, Oregon and recovered.

“We cannot tell you at this time how and why,” she says. “We will have that information, it’s going to take time, we are going to have to analyse the components.”

According to NTSB aerospace engineer Clint Crookshank, there are 12 stop pads on the door frame in the fuselage, and 12 stop pins on the door plug. For the door to be secured in place, they must meet and push against each other.

“To install that plug in the fuselage, you rotate it up so that the plug stop is above the door stop, it translates inboard and down so that the stops engage,” he says. “Four stop bolts are installed in the mechanism. There is a guide roller on each side, on the upper side of the door frame, that engages with a guide fitting on the plug.”

“The examination shows that all 12 stops became disengaged allowing [the door plug] to blow out of the fuselage. Both guide roller tracks were fractured,” Crookshank adds.

“The door translated up, disengaged from the stops, and fractured the fittings.”

“We have not yet recovered the four bolts that restrain it from its vertical movement, and we have not determined if they existed there,” Crookshank adds.

Why all that happened shortly after the aircraft took off is still a mystery, though, the investigators say.



https://www.flightglobal.com/safety/gui ... 07.article

[MN-Skeptic]

Stone Cold Jane Austen
@AbbyHiggs

“When one door closes, another opens.”

— Boeing

[Frater I*I]

Loose bolts? That may be a serious quality control problem at Boeing. The video by GG above shows that all bolts ought to be secured by a pin against accidential loosening.

Called a cotter pin...

The guy in the vid says it's "lockingwire" [correct term would be lockwire] but it's not, that is a different form of safetying...

[Frater I*I]

I wonder if there is a certain element of zipf's law here. On the line I am familiar with, their big thing is making sure there is no debris in the aircraft. Signs all over the place about checking for parts or tools or garbage, but not a single sign highlighting that you have to tighten every single bolt.

Not a sign per say, but such instructions would be in the tech data for the installation of the plug, something that the person installing it would have to have while doing the task per FAA regulations...

[neeneko]

Not a sign per say, but such instructions would be in the tech data for the installation of the plug, something that the person installing it would have to have while doing the task per FAA regulations...

Sometimes people need large brighty coloured signs to remind them to do the thing they are already supposed to be doing.

[raison de arizona]

Boeing CEO acknowledges ‘mistake’ related to terrifying Alaska Airlines flight

Boeing CEO David Calhoun acknowledged the company’s “mistake” in the wake of the Alaska Airlines incident at a staff-wide “safety meeting” Tuesday.

“We’re going to approach this number one acknowledging our mistake,” Calhoun told staff, according to a partial readout of the meeting shared with CNN. “We’re going to approach it with 100% and complete transparency every step of the way. We are going to work with the NTSB who is investigating the accident itself to find out what the cause is.”

A company source told CNN that the company believes “the mistake in question” was introduced in the aircraft’s manufacturing supply chain, however it is not yet known if Calhoun identified any specific error during the presentation.

The source said the meeting also included a reminder of the seriousness of the situation. Employees were told that the company’s Chief Safety Officer is now in charge of the 737 Max fleet, the source said. Mike Delaney is Boeing’s Chief Aerospace Safety Officer.

https://www.cnn.com/2024/01/09/business ... index.html

[qbawl]

Not a sign per say, but such instructions would be in the tech data for the installation of the plug, something that the person installing it would have to have while doing the task per FAA regulations...

Sometimes people need large brighty coloured signs to remind them to do the thing they are already supposed to be doing.

Sort of like the summer job I had running a crew laying sod. I sat in the tuck and every 10 - 15 minutes yelled out the window, "Green side up!"

[neonzx]

And will they now release the 737 Max PRO edition?

I really hate that I have to check what equipment I am flying on when I book a flight.

[RTH10260]

And will they now release the 737 Max PRO edition?

I really hate that I have to check what equipment I am flying on when I book a flight.

They will ground it the day after your flight

[RTH10260]

NTSB at their press conference: they are not even sure that the missing bolts were even there

https://youtu.be/L92zwvkr1pQ

[Foggy]

... and they aren't going to find the bolts in somebody's back yard.

[raison de arizona]

For the 777, Boeing put their heads of software engineering on the test flights.

For the 737 Max, Boeing outsourced the software testing to $9 an hour contractors in India.

Decline is a choice.

[Frater I*I]

For the 777, Boeing put their heads of software engineering on the test flights.

For the 737 Max, Boeing outsourced the software testing to $9 an hour contractors in India.

Decline is a choice.

[/quote]

And the reason for the two hull losses the MAX has suffered...

[RTH10260]

Software cannot compensate when hardware redundancy does not exist in the first place.

[neeneko]

Software cannot compensate when hardware redundancy does not exist in the first place.

No, but it does hint at how the company views its testing process. Reducing the cost and time of testing has been a big part of Boeing's strategy.

[much ado]

NTSB at their press conference: they are not even sure that the missing bolts were even there

https://youtu.be/L92zwvkr1pQ

That was my guess, based on the lack of damage to the cams in the upper part, as shown in the video. Bolts don't really have to be tight, they just have to be present. As long as they are there, they prevent the plug from opening. But the video did not show the condition of the lower part of the opening where the other two bolt were...

So who did it? Was it during assembly at Boeing? Or was it by maintenance checking for leaks? My guess is Boeing, which would probably mean at least two complete fuck-ups, first, the person who was supposed to put the bolts in place, and second, the person who was responsible for checking that the assembly was done correctly.

I'm sure frater knows better than I do.

[Frater I*I]

That was my guess, based on the lack of damage to the cams in the upper part, as shown in the video. Bolts don't really have to be tight, they just have to be present. As long as they are there, they prevent the plug from opening. But the video did not show the condition of the lower part of the opening where the other two bolt were...

So who did it? #1Was it during assembly at Boeing? #2 Or was it by maintenance checking for leaks? My guess is Boeing, which would probably mean at least two complete fuck-ups, #3first, the person who was supposed to put the bolts in place, and #4second, the person who was responsible for checking that the assembly was done correctly.

I'm sure frater knows better than I do.

#1: Yes

#2:: the aircraft was never put into maintenance after the pressurization issues had be reported by the previous day's flight crew. It should have been.

#3: Indeed, this person was not following his tech data, at minimum, he'll be on the unemployment line, if he has an A&P certificate like me, welp...happy suspension time...

#4: Often called QC or Inpection...that person defiantly has an A&P and will be on the unemployment line with a suspended certificate.

And as I posted before the airline will be looking at fines for not adressing the issue when reported by the aforementioned flight crew...

[raison de arizona]

#2:: the aircraft was never put into maintenance after the pressurization issues had be reported by the previous day's flight crew. It should have been.

And as I posted before the airline will be looking at fines for not adressing the issue when reported by the aforementioned flight crew...

So how sound was their alternative plan, Don’t Fly Over Water? Is that a thing? It seems like if a plane is not safe to fly over water, it probably isn’t safe to fly at all.

[Sam the Centipede]

Off Topic

Prompted by this bolts issue but not germane to this specific incident:

A tv program with a title something like Air Crash Investigated (or perhaps Reconstructed) had an episode about a British plane, a BAC-111, in the 1990s which had the pilot's windscreen blow away in flight at 17,000 feet or thereabouts, sucking the pilot half out of the cockpit and causing immediate depressurization of the plane, and intense fogging. Two cabin crew held into the pilot's legs while the copilot arranged and executed an emergency descent and landing. The crew assumed the pilot was dead but held on - the narrator drily pointed out that even if the pilot were dead (spoiler, he wasn't, unconscious, frostbite, and a couple of broken bones, that's all) it was wise to hold on because the body could have flown into the rear mounted engines, not good.

Bolts, yes! The windscreen was secured by bolts from the outside, so the bolts held it in place against the pressurization (I don't know why the designers chose that way round). It had been replaced by an overnight maintenance crew. In a crowded hangar the technician had removed the windscreen and decided to replace the bolts when reinstalling its replacement (I might be wrong on it being a replacement, i can't remember why it had to come out).

The technician decided to renew the bolts. But he didn't look up the correct bolt in the manual/list and ignored a comment from the stores guy about the expected size of bolts but instead found some bolts which he compared and judged to be the same. This is when luck ran out. Some (all?) of the bolts he had removed were not actually the correct size but a size smaller. The windscreen wasn't to spec to start with. And when the technician picked his new bolts they were about two thousands of an inch shorter.

He was working high up in a cramped space in a hangar, leaning over to get at the work area, so he didn't notice (as he might have in more ergonomically appropriate conditions) that perhaps the bolts weren't tightening with the expected feel.

The program said the technician was a conscientious worker and believed he was doing right, but that that episode caused authorities to reflect on avoiding similar issues.

As I said, this is not germane to this door issue, but it's interesting how very important these human factors issues are. The machinery itself is rarely the prime or single cause when things go badly wrong.

[RTH10260]

as above image in article https://www.nzherald.co.nz/travel/image ... YPI7UR54A/


the Wikipedia writeup https://en.wikipedia.org/wiki/British_A ... light_5390



Incident retold by the Mentour Pilot

[Reality Check]

The FAA has indefinitely grounded all the 737 Max-9 fleet indefinitely until they review this door plug issue. Wonder how many other potential issues are out there?

[Suranis]

United Airlines flight to Chicago makes emergency landing in Tampa after door indicator light turns on

https://wgntv.com/news/national/united- ... ns-on/amp/

I cant read it as its region restricted. but apparently it was an Airbus, not a Boeing plane but the article barely mentions that.

[raison de arizona]

United Airlines flight to Chicago makes emergency landing in Tampa after door indicator light turns on

https://wgntv.com/news/national/united- ... ns-on/amp/

I cant read it as its region restricted. but apparently it was an Airbus, not a Boeing plane but the article barely mentions that.

Yes, it was an Airbus a319. The article states "The aircraft that diverted to TPA was not a 737 MAX 9, like the Alaska Airlines plane that had a door blown out mid-flight." but I think that is the only mention.