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

[1503-44]

Yeah OK. Anyway I solved my problem in 2018.
My ticket purchase app will not proced to checkout when
If InStr(AC_TYPE, "max") = True
Print "WARNING Unapproved AC Type"
Exit Sub

Think I must change "max" to "boeing"

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

 

[MintJulep]

Seems like wishful hoping for all 12 stop pad/fittings to share the load anywhere near equally.

What actually holds the pressure in?

 

[TugboatEng]

If you look at the construction of the door the horizontal stiffeners are quite robust while the vertical stiffeners are slender. This means the door will be somewhat flexible about a horizontal axis which will help it share the load amongst the stop fittings vs a more rigid door.

 

[Alistair_Heaton]

The structure has to take negative pressure 0.5 PSI I think it is before the safety valve triggers to prevent implosion.

I presume the stop pads are to distribute the load to the rest of the hull structure. Any less and you would have to beef up the ribs and stringers. And have cylindrical buckling issues.

The pressurisation system is meant to control things so you don't blow the ears out of everyone onboard. So you really want 500ft/min or less. The aircraft can descend and we do at over 3000 ft/min, above 10k, most company's have limits to reduce that to some max value below that. But 1500/2000ft/min is normal. Cabin at 41k will be at 8000ft. Which gives 14 mins to get it down to sea level (it actually lands with -500ft) . The aircraft can do it in less than 13 mins. So you "catch the cabin" so things have to be protected against implosion.

Again its a 1960's system... Modern aircraft have a schedule which is linked to density and perceived pressure change on the ears so work on a rate of pressure change. So may start off at 800-1000 ft/min high up then reduce to 350ft/min at lower altitudes. I have never managed to catch the cabin on the A220 and I have done some border line emergency descents rates due to Air traffic restrictions. Q400 it was almost daily.

 

[1503-44]

$ 13B (8%) loss in the market value yesterday. That will go lower still.

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

 

[MintJulep]

There is some sort of fastener in the stop fittings.

Perhaps to hold on a wear pad and shims?

 

[RobWard]

I'm thankful the door missed the tail on the way out - I believe that's brought down aeroplanes in the past.

"I love deadlines. I love the whooshing noise they make as they go past." Douglas Adams

 

[Alistair_Heaton]

An update brief

https://www.youtube.com/watch?v=kGWLBLb9Pm4&t=1s

I must say I am well impressed with that lady. Excellent communicating technical content without dumbing down.

And she obviously "gets" the engineering and understands it.

 

[Alistair_Heaton]

Seems on the door there is evidence of fractured guide fittings.

 

[Murph 9000]

Looking at the relative size of the guide fittings and stop fittings, I think the guide fittings will remain engaged after the plug has moved upwards off the stop fittings, transferring the full pressure load onto the guide fittings and hinges. That makes the fracture unsurprising to me, and a consequence rather than a cause of the problem.

 

[Alistair_Heaton]

As an aside I had 3 pax out 280 moved yesterday ask me about if we had something similar.

One had asked the cabin crew who pointed them towards me.

The public are definitely getting more upfront asking about stuff in the media.

Explained what had happened to the CC during the cruise and the next two they dealt with themselves. Much too thier own amusement after they got a compliment by another pax listening in about thier technical correctness. Which they blamed on me...

 

[Tomfh]

Those connections look pretty flimsy. Is that sort
of thing common in aerospace?

 

[Ng2020]

Such connections are not uncommon in aircraft structures. The plug in question not an especially novel design. It utilises the same means of attachment as the functional emergency exit door it replaces. That exit door configuration existed on 737s prior to MAX.

 

[Alistair_Heaton]

Humour that's doing the rounds

 

[waross]

OMG. Voice recorder overwritten (when the 2h loop reinitialized ???).

Freaking incredible.
The micro chip in my dash cam records good quality video, speed, time and GPS coordinates.
It will run several days before over-writing.
Voice recording? The chip in my dash cam would probably record weeks of audio before over-writing.


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

 

[Murph 9000]

Looking at the relative size of the guide fittings and stop fittings, I think the guide fittings will remain engaged after the plug has moved upwards off the stop fittings, transferring the full pressure load onto the guide fittings and hinges. That makes the fracture unsurprising to me, and a consequence rather than a cause of the problem.

Having just watched today's NTSB media brief, this was actually stated in it by one of the lead investigators, at 29:12 in the livestream.

NTSB Media Brief - Alaska Airlines Flight 1282 (Jan 8) livestream @ 29:12

 

[cranky108]

Why do you need a dash cam? So you can record other bad drivers? What are you going to do with it?
I have one, but only because it was on sale, at a good price.

 

[waross]

If it's Boing, I'm not Going.

Boing??
I've checked the spelling several times:

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

 

[TenPenny]

A couple of years ago, when Boeing was going through a rough patch due to the 737 (no, this wasn't after the MCAS thing, it was more recent than that), I picked up some shares at $121 per share...They're still ok now at what, $229, but I maybe should have cashed out at $250.

The question is, should I pick some up now?

 

[TugboatEng]

Quote:
OMG. Voice recorder overwritten (when the 2h loop reinitialized ???).
Freaking incredible.
The micro chip in my dash cam records good quality video, speed, time and GPS coordinates.
It will run several days before over-writing.
Voice recording? The chip in my dash cam would probably record weeks of audio before over-writing.

A few years ago, at SFO airport, an Air Canada flight lined up with a an occupied taxiway for landing. There would likely have been well over 1000 casualties if the plane impacted the other loaded planes on the ground. They came within 15 feet of crashing. The flight data recorder was not preserved. No disciplinary action was taken. Good news, they stopped using that flight number.

https://en.m.wikipedia.org/wiki/Air_Canada_Flight_759