Alaska Airlines flight forced to make an emergency landing... 82

[dik]

Maybe Boeing is looking for new employees... and management thought it was a posting by them?

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Alistair_Heaton]

It's more likely it's taxing and takeoff runway lights it gives the high g bumps

 

[EdStainless]

https://leehamnews.com/2024/01/11/a...ity-assurance-at-boeing-or-spirit/#more-43658

This is a good discussion of the situation. My guess is that every Boeing plane (of any model) with a plug in place of a door will be subject to added inspections.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Alistair_Heaton]

I think all makes will be checking the pins required or not...

Although I can't think of others with plug doors. But I am particularly talent limited on spotting and aircraft specs unless I have to waggle a stick of one

 

[dik]

"Some Boeing critics and the uninformed suggest that the door plug is a remnant of the 1997 merger with McDonnell Douglas Corp. and that MDC-inspired cost-cutting led to the door plug design. Some others suggest the same cost-cutting culture is responsible for launching the MAX.

Both of these theses are wrong, fundamentally because this is a quality control issue and not an airplane issue like the MCAS design. But on the facts, the origination of the MAX was a parallel design study against a new airplane design during the years leading up to the July 2011 launch of the MAX."

That doesn't make me feel any more comfortable... and I'm not sure it is true.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Alistair_Heaton]

Nah it dates back to the 1960's and prior approval.

It was legal on the NG so don't change anything even if it's safer

Although to be honest in this case I really thing it's a quality issue not design

 

[JohnRBaker]

It's been reported that a second Apple iPhone has been found that had fallen from the Alaska Airlines flight which lost the door over Portland. And yes, it was still functional with little or no apparent damage.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[jrs87]

Is this senior plausible? *

1. Exit is open and ready to be closed.
2. Plug was pushed down against the springs and the top tracks and roller pins seated.
3. Two upper cross locking bolts are forgotten but the spring does not push the plug upward and out of the tracks because the stop pads are conical in the fit functions as a strong enough detent.
4. Over time the springs work the plug up leading to leaks detected 3 times.
5. Under flight pressure the stop pads instead of mating, pop past each other and the door blows out.

*Are the stop pads indeed conical to any degree?
By the way, I know of the two upper lock bolts, I hear of two lower lock bolts but have not seen them. The hinge spring over-travel arrester bolts do not lock the plug or do they? As a whole, this method of plugging the exit seems sketchy.
p.s. I like the term anti-defect used by 3DDave.

 

[Murph 9000]

I'm pretty certain the bolts which pass radially through the green collar and hinge extension tube are the lower locking bolts, not over-travel bolts. There's a nut and washer on the end (top when closed) of the hinge extension tube, which I believe is to prevent the plug coming off the hinges when open.

 

[Alistair_Heaton]

what's the deal with locking wire?

 

[Murph 9000]

New from the 737 tech YouTube channel, clarifying the design and function of the plug, and a few new details (e.g. the stop fittings on the plug have adjustable stop pins secured with lock wire):

737 Technical Aspects of AS1282 FAQs

 

[1503-44]

I don't see Alaska Air as entirely blameless. They had a high enough concern to severly restrict operations of the AC. That indicates it had some probability of failure, apparently from depressurization, yet they restricted the maximum distance from a runway. That makes no sense at all, if the worry is about decompression. If I'm worried about pipeline blowouts, I restrict the operating pressure, not how far I can pump product. The plane's maximum altitude should have been restricted. This makes the lack of a major disaster just freeking luck. That don't cut it for me. Yet Alaska Air isn't catching any sh!t at all.

"And she said Alaska’s decision to restrict the jet from long-range routes over water was not required by regulations but was a precautionary measure the airline takes voluntarily to provide an additional safety margin when any important systems show any sign of a repetitive problem."

If that is true, what exactly was the reason for the restriction? Just "too many alarms"? Nobody looked at the alarm log and said, uh it's a pressure problem. Nobody looked to see what the hell it was and deduce the appropriate flight restriction. Really? Nobody?

"Intermittent warning lights indicating a brief reduction in cabin pressurization had occurred on flights of this new MAX 9 on Dec. 7 and then again on Jan. 3 and 4, (2 in the previous) two days before the incident."

They had 3 warnings. Increasing in frequency. That is in itself a signal of increasing danger. Then they reach a daily basis. What the hell are they thinking. Keep the plane flying! Just when, or how many warnings does Alaska Air need to stop and figure out what's wrong? 2 per day? 3? 5? What's their limit? It's obviously much higher than mine. Do I have to ask "Hey, how many warning lights did you get lately" each time I board. It looks to me like they are not interested in passenger safety at all. Just giving lip service.

Homendy said the policy to restrict it from doing so at any sign of a system issue is “an extra step that Alaska Airlines put in place.”

Guess what. That does no good, none at all, if you do not take the right precautions. FAA, time for a new regulation. PROMENATELY POST THE NUMBER OF WARNING LIGHTS RECEIVED IN THE LAST 30 DAYS and ANY CURRENT RESTRICTIONS ON OPERATIONS OF THE AC. POST IT ON THE PASSENGER ENTRANCE RAMP IN 8" TALL LETTERS. I'll make my own decisions, thank you. With immediate 4x ticket cost cash refunds for anyone deciding not to take their joy rides.

I want to know exactly when an airline can make you fly on whatever POS that they decide to field at the other end of the boarding ramp. What exactly classifies as "not flight worthy", besides the obvious. Are all warning lights ? Doesn't look like it.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[jrs87]

Hi Murph9000,

Thanks, the video you linked to sends my entire contribution to rubbish bin. Good find.

https://youtu.be/kKSNdqtG3dY

 

[MintJulep]

Referencing this video: 737 Technical Aspects of AS1282 FAQs

If the stop pins are not adjusted correctly then pressurization loads will be taken through the guide track and roller. Given that there are stop pins and stop pads that are intended to transmit the pressurization loads, we could speculate that the guide track and roller are not designed for pressurization loads.

This might explain the reported fracture of the guide track.

Also, if the stop pins are not adjusted correctly, then pressurization will cause the plug to move outward more than intended. This would relax the gasket, possibly explaining the reported depressurization alarms in the days prior.

 

[1503-44]

But, but

we have no indications whatsoever that this (decompression warning lights) correlated in any way to the expulsion of the door plug and the rapid decompression.”

Shush. Nobody even suspects. The probability is only 99.9999

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[jrs87]

New speculation, Boeing accidentally switched the door with another Spirit fuselage's door. The mismatched micro adjustments went unnoticed. This presumes Spirit was responsible for the adjustments.

 

[waross]

"But Homendy said she believes these three incidents are likely unrelated to the door plug blowout and that Alaska’s decision makes sense."
Three pressurization alarms followed by a plug blowout, "likely unrelated"
There goes my respect for Homendy.
Note to Alaskan; The next time that you get a pressurization alarm it may be prudent to check that all the doors and plugs are secure.

And this from Boing;

CEO Dave Calhoun, the new Chief Operating Officer Stephanie Pope, Chief Safety Officer Mike Delaney and Stan Deal, CEO of the Commercial Airplane division, all spoke at noon before about 500 employees in the factory where the MAX is assembled. The meeting was webcast to all Boeing employees.
He said Boeing will try to restore airline confidence by “our willingness to work directly and transparently with them, and to ensure they understand that every airplane that Boeing has its name on that’s in the sky is in fact safe.”

The check's in the mail
and
I'm from the Government NTSB and I'm here to help you.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[MintJulep]

The more I look at this the worse I think the design is.

Depending on many variations for component dimensions and assembly variation, as the plug is moved down the interaction between the Upper Guide Roller and the Upper Guide Track might pull the plug inwards, or it might push the plug outwards.

 

[3DDave]

I believe the pin bracket is adjustable, hence the use of bolts rather than rivets to fix it to the fuselage.

 

[dik]

Was there a huge change in Boeing quality after McDonnell Douglas took over? Douglas' manner of doing business?

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik