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

[dik]

I used to have a Corsair Corsa... it was a really neat car... once you got use to handling it, there was no issue... not a lot different than the Volkswagen or the Porsch 911... the 911 had the handling worked out a little better.

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

-Dik

 

[dik]

3DD... excellent clip

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

-Dik

 

[SnTMan]

Ralph Nader was wrong

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[dik]

concur

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

-Dik

 

[thebard3]

The Corvair and Pinto got all the bad publicity, mostly undeserved. The 737 MAX is definitely deserving of bad publicity. Boeing as a whole really seems to have lost it's way.

Brad Waybright

The more you know, the more you know you don't know.

 

[1503-44]

Its not a production QA problem, Now it's a corporate cultural issue.

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

 

[MintJulep]

I'd be very interested to see the plug on the opposite side of the plane.

 

[waross]

Its not a production QA problem, Now it's a corporate cultural issue.

Or a corporate cultural problem lading to production QA problems,
Either way,

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

 

[SWComposites]

The culture problem started with McD buying Boeing in 1997.

 

[thebard3]

The saying is that McDonell Douglas bought Boeing with Boeing's money.

Brad Waybright

The more you know, the more you know you don't know.

 

[waross]

And wasn't that because McD was going down the tubes partly as a result of their culture problem?
If a culture disrespects engineers, eventually they will no longer have the top tier of engineering talent available.

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

 

[waross]

I thought that that was;
Boing bought McD with McD's money.

But think about it;
A door blowing out in flight.
That must have been incredibly distracting.
Something like that could result in the pilots forgetting to turn off the anti-icing heaters.

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

 

[JohnRBaker]

The saying is that McDonell Douglas bought Boeing with Boeing's money.

While this all happened six years after MDC sold our division to EDS, this isn't how we heard it from our old workmates, although in the end, the new Boeing logo did bare an amazing resemblance to the old McDonnell Douglas logo:

Prior to the 1997 acquisition of MDC by Boeing, the Boeing logo consisted of just the word 'Boeing'.

And for the record, I'm drawing a monthly pension from Boeing, a company I never worked for. But then, I'm also drawing a monthly pension from HP, another company I never worked for.

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]

https://www.youtube.com/shorts/K6hephOelG0?feature=share

The way the large doors have to move inside first before the door opens has always made me confident. A plug of this size that depends on just bolts may not be as failsafe.

Why did this plug popout? Who at Boeing is feeling queasy right now?

 

[jrs87]

https://youtu.be/DumCQPPjkbA

 

[Alistair_Heaton]

I am not sure there would have been the door + frame sitting there covered up.

They want to keep the weight down. Those doors weight plus frame must be around 200kg each. Your not going to fly around nearly a ton of extra metal which does nothing. Apart from anything else it decreases the traffic load by having a higher basic mass plus increases the fuel burn. A220 fuel burn increases by 60kg per 1000kg of weight per hour. That's why its an option which only high capacity airline's go for to be able to get more seats shoe horned in. An extra 50kg per hour doesn't sound much but when the thing is in the sky 12 hours a day that's 600kg. That's 219 tons of fuel per year at 700$ per metric ton. So basically 1.5 million over 10 years.

There are also no rivet holes on the skin round the hole plus no damage to the surrounding skin.

I have zero clue what they might have put instead in that failed. Just don't think it will be what's depicted in the picture. I am quiet happy to be wrong though.

Note the calculation above is done with me thinking there are 4 of these unused. If its only two of them divide by 2.

 

[Murph 9000]

Going by the following video (already posted by 3DDave above), the bolts do not hold the non-door plug against pressurisation. It looks to me like the non-door plug is essentially the same structure as a door, but with all of the extra bits removed (i.e. the opening handle and mechanism, pressure equalisation vent, slide, etc), and a full size window instead of the smaller port hole.

737 Mid-Cabin Emergency Exit Doors

As I interpret it, the plug slides downwards (the same as a door, if fitted) behind "stop fittings", and the bolts just prevent it from sliding up again. The air pressure pushes the structural fittings on the plug or door against the structural fittings on the frame, and the bolts should only have minimal stress on them (relative to the in-service maximum of around 8psi (I'm not certain of the max delta on the 737 MAX, but it should be around that) multiplied by the door area from pressurisation). I'm not saying the frame is exactly the same frame used if a door is fitted (it may or may not be), only that the mechanism that resists the pressure looks to be essentially the same.

Purely speculatively, I'm wondering if someone either forgot to fit the bolts, or used insufficient torque or Loctite on them.

 

[3DDave]

Anyone who hasn't done so - watch the video I posted a link to. The weirdness of the speculations is freaking me out.

Yes, some airlines opted to put an emergency exit door, but inoperative, in place. Others went with a plug door. The inop door means they can reconfigure the seating and interior panel without having to recertify the plane. The plug door means they believe they will never recertify or are willing to eat the cost.

JRS87 - the second video you linked to - that's a different situation caused by a passenger. The plug door that escaped uses the same plug features as Airbus does on all their main doors. The bolts that are installed on the escaped door were supposed to keep the door from moving up to unalign the capture fingers around the door. The features that keep the door from moving outward are the capture fingers, again, the same as Airbus uses on their main doors.

The fasteners are to have castellated nuts and cotter pins. Even without that there is a spring load to supply some friction.

One mystery for me now is that the door has to come in before it can move up, so how was that possible with the plane pressurized? If all the bolts had fallen out (just being loose would not allow movement) then why did this not happen during the taxi process with much vibration and no pressure? There are retaining straps that hold the door from fully opening, so if the door popped open during taxi they would not have been able to pressurize the plane. Or, maybe, that is what happened and the interior cover is what kept the pressure in up until it could not do so any longer and the failed interior cover pushed against the open door and broke the retaining straps.

A passenger could have noticed the wall of the plane was no longer where it should be, but we'll see if that comes out. They may not have realized what it meant or no one was paying attention. The seat next to the panel was unoccupied, so no one would be leaning against it to feel it move. They could also have seen the window was 5-6 inches farther out than all the other windows and not aligned with the interior trim opening by the 1.5 inch vertical movement to release it.

Additionally perplexing is they had pressurization issues reported, but if the door hasn't moved in then why was the door seal not functioning correctly?

I can picture that the door has been loose for a while, the bolts all out, and the door lift spring pushing up and allowing the seal to open just a tiny amount. Then, when pressure is applied the door pushes back and down, sealing correctly. But if the interior panel has been preventing the door from moving fully up in the past, then why did that happen this time?

 

[Alistair_Heaton]

Do you know what the weight penalty is between the two?

 

[Cool_Controls]

Is the strap assembly left in place on these plug doors or is it only installed during maintenance operations?