Alaska Airlines 737-900 MAX loses a door in-flight out of PDX

[MLHeliwrench]

Originally Posted by Feathered

The NTSB, Alaska Airlines, Boeing, and Spirit Aerosystems owe Mr. Sauer some thanks for going outside on a dark rainy night to search for missing Boeing parts. Amazing that the door plug, two mobile phones, and an airline IFE headphones pair were found relatively undamaged.
From The Oregonian:


https://www.oregonlive.com/portland/...r-in-yard.html

I love local interest stories for quips like this:He showed off the National Transportation Safety Board “Special Operations” patch and a NTSB board member medallion, with the board chair Homendy’s name on it, as his souvenirs.

Sauer said he’s been receiving interview requests from media around the world. Due to his unexpected moment in the spotlight, he lamented Monday afternoon that he’s getting behind on grading and getting reports in on his student’s grades before the end of the semester. He is looking forward to taking a group of students cross-country skiing in Montana this weekend. They’re going by train.
”I’m curious to what actually happened that caused this,” he said. He said he’s thankful no one was hurt.Now, he signs all his notes and emails: “The Bob, finder of missing aircraft parts.”

[lateott]

Originally Posted by dragon6172

The 15 year old was likely in Row 25. You can see in the video taken in flight that the same fella is sitting in 26C. Also, after landing you can see the flight attendant come and ask if anyone had been sitting in 26A/B and being told no. Then you can see, but can not hear, him gesture towards the empty seats in Row 25, passengers point towards the RH side of the aircraft and forward. Which would match the news story you linked.
Video:
https://twitter.com/bradhowardnews/s...vrMrEKFMELDFVQ

Yes, thanks, I think you are right. I see that same passenger now in 26C at 0:17 and 0:19 of the TikTok video.

I can also imagine 15 year old "Jack" telling the witness Kelly Bartlett, to whom he moved to sit adjacent, that he was in "the row." If he was in 25A it must have felt the same, and his seat is the one that is deformed and twisted backwards with a missing head cushion. "Kelly" would not have known the difference because she was a few rows forward and must have gotten her info from "Jack."

[Grummaniser]

One additional observation - on the NTSB photo of the door with the polythene sheet and the "2" annotation in red. This appears to show the lift-assist slide together with the bracket that normally attaches it to the frame. This is the same bracket shown in another photo with loose bolts. I believe that second photo was of an aircraft which was picked up during the AD inspection.

[lateott]

Originally Posted by Feathered

The NTSB, Alaska Airlines, Boeing, and Spirit Aerosystems owe Mr. Sauer some thanks for going outside on a dark rainy night to search for missing Boeing parts. Amazing that the door plug, two mobile phones, and an airline IFE headphones pair were found relatively undamaged.
From The Oregonian:


Bob Sauer, a science teacher at Catlin Gabel, was monitoring the news over the weekend about the blown-out door plug from the Alaska Airlines flight over Portland, but it wasn’t until Sunday night that he searched his yard — after his ex-wife called and alerted him that authorities suspected the part might have landed nearby.

Sauer, 64, grabbed a flashlight and decided to check around his house around 8 p.m. Sunday.

It was dark and raining out. As he stepped around the corner of his house, he shined his light along a bank of cedar trees that he and his children had planted about 20 years ago to separate his property from his neighbor

https://www.oregonlive.com/portland/...r-in-yard.html

Great story!

Door landing geolocated here: 45.516377457813434, -122.77628750905718

I believe phones were found on Barnes Road 1500-3000 feet away.

[Capn Bloggs]

Phones, Hats...

[Consol]

Originally Posted by Grummaniser

One additional observation - on the NTSB photo of the door with the polythene sheet and the "2" annotation in red. This appears to show the lift-assist slide together with the bracket that normally attaches it to the frame. This is the same bracket shown in another photo with loose bolts. I believe that second photo was of an aircraft which was picked up during the AD inspection.

Correct, last pic is from a United 9 Max. Question is did the bracket in the earlier pic come loose causing the failure or was it wrenched out by the air loads after the door had already failed and opened?

[Old Ag]

Originally Posted by Consol

Correct, last pic is from a United 9 Max. Question is did the bracket in the earlier pic come loose causing the failure or was it wrenched out by the air loads after the door had already failed and opened?

Likely it is the latter as the failure of one of the slide assemblies by itself, would not let the door translate upwards and depart the aircraft. At worst, a failed slide would have the door pressed against the lugs or pads at three spots which should still be enough to hold the door firmly against the pads even when depressurized. If both sides were to fail, then the bottom of the door could come off the lower pads as it moves inward in its frame. But with the upper bolts in, the door still couldn’t open. But it could move slightly away from the frame until pressurization pushed it back up against the pads.

A damaged or disconnected hinge slide would make for a nasty surprise if one attempted to open the door like that.

[ozaub]

My theory at #467 is entirely consistent with earlier pressurisation issues. On prior flights plug jiggled up just a fraction before pressure locking against contour pads. Then dropped back into positron under gravity when cabin depressurised. It would take a particular timing of turbulence and pressurisation before plug ejected. We’ll know soon enough

[lateott]

Originally Posted by Old Ag

Likely it is the latter as the failure of one of the slide assemblies by itself, would not let the door translate upwards and depart the aircraft. At worst, a failed slide would have the door pressed against the lugs or pads at three spots which should still be enough to hold the door firmly against the pads even when depressurized. If both sides were to fail, then the bottom of the door could come off the lower pads as it moves inward in its frame. But with the upper bolts in, the door still couldn’t open. But it could move slightly away from the frame until pressurization pushed it back up against the pads.

A damaged or disconnected hinge slide would make for a nasty surprise if one attempted to open the door like that.

Also the spring seems to have sprung, so there is no retention bolt in place for the retained spring assembly. One of the images may show the empty retention bolt hole. Of course the retaining bolt could have sheared as the door was being ripped off. Interesting to see 2 different failure points for the 2 hinges.

[Edoil17]

In The photo of the bracket assembly with the loose bolts.

I find it hard to understand how all the bolts, would have able to become loose and be jostled / rotated, wriggle free?

The assist spring appears to be compressed, forcing the bracket assembly upwards against the bolts in the holes, so I think one, or more of bolts is likely to be a "Key Bolt" the last remaining bolt, taking the force of the spring, and be in a state of shear for some time, whether this spring force and jostling would actually lead to failure or not? Who knows? Just really curious to see outcome of this investigation.

[Chris2303]

Originally Posted by Maninthebar

The advance of technology and reduction in cost makes it VERY hard to understand why on-board systems are limited to 2 hours voice

Because, in it's apparent wisdom, the FAA has so far declined to mandate longer, even though the on board recorder can support a lot longer than 2 hours

[tsumini]

Questions;
1. Does this AC have RH plug/door?
2. If so has it been examined for this AD?
3. If so what are the results?
4. Are plugs interchangeable RH.>LH?

[MJA Chaser]

"final bolt worked its way out during the incident flight"

I wonder where it and the others are then? Can we get Bob to have alook around inside the aircraft with his torch?

[AerocatS2A]

https://news.alaskaair.com/alaska-ai...tions/as-1282/

More loose hardware found, by Alaska this time.

We continue to wait for final documentation from Boeing and the FAA before we can begin the formal inspection process.

As our maintenance technicians began preparing our 737-9 MAX fleet for inspections, they accessed the area in question. Initial reports from our technicians indicate some loose hardware was visible on some aircraft.

[Big Pistons Forever]

R

Originally Posted by AerocatS2A

https://news.alaskaair.com/alaska-ai...tions/as-1282/

More loose hardware found, by Alaska this time.

Uh huh

[lateott]

To be more clear:

1. Tonight NTSB said "we know what broke. We don't know why or how."
2. They found that the guides on the door plug were fractured.
3. The failure occurred because the door plug translated upwards, and the stop pins disengaged from the stop fittings.
4. They don't know whether the 4 bolts which exist to prevent the door plug from translating upwards were in place, they have not found the bolts.
5. The door plug is being shipped to their lab, and they believe they can determine in the lab whether the bolts were installed.

NTSB Video Press Conference

[MLHeliwrench]

To add to your list of highlights:

- the right hand plug was fully inspected by the NTSB and found to be installed correctly.

- spirit aero systems was invited to be a party to the investigation. (The tone of this remark, along with the fact they can’t find the four retention/lock bolts points a certain direction. - my interpretation)

- the NTSB had no comment on reports of missing / loose bolts found during checks of other aircraft by United and Alaska - talk to FAA about that.

- further clarified that the fractured guide rails on the plug door broke as a result of the door sliding up off the retention pads. The four bolts are meant to stop this upward slide.

- at this time the previous few pressurization system snags appear to have nothing to do with the blow out. They will however analyze the FDR and pressurization system controllers (which have an internal memory) for any correlation

[aeromech3]

Back in LHR 1969 a wheel change on a BAC1-11, time and motion bod watching, 20min turnaround was their target, axle nut tightened to a hi load then backed off (maybe twice) and final torque of axle nut followed by a locking bolt and slotted nut and split pin; some flight cycles later a station engineer changed the same wheel and reported it was loose when removing, big inquiry which my Mechanic had to attend.
Fast forwards circa 1973, licensed and looking after Caribbean BAC 1-11's, along with contract mechanics from an American airline, change wheel, slotted nut and split pin for locking bolt, some time later same wheel position found lock bolt with only stiff nut, reason given: easier, I had never seen them used on my side of the pond!
Likely the semi plugs were, even with modern manufacturing methods, dedicated serial numbered, during outfitting and painting likely the plug was installed and removed several times with easy fit locking pins being used.
Now QA will no doubt point out that the task card is there to be followed for the final assembly and duly stamped off, pointing a finger towards QC at same time.
Other loose hardware is going to be hard to explain and I am a little surprised that bolts were used and not a hi-lock type fastener or was this another easy fit?

[incompleteness]

Originally Posted by lateott

To be more clear:

1. Tonight NTSB said "we know what broke. We don't know why or how."
2. They found that the guides on the door plug were fractured.
3. The failure occurred because the door plug translated upwards, and the stop pins disengaged from the stop fittings.
4. They don't know whether the 4 bolts which exist to prevent the door plug from translating upwards were in place, they have not found the bolts.
5. The door plug is being shipped to their lab, and they believe they can determine in the lab whether the bolts were installed.

If any of the bolts were installed and were pushed out of the way by some mysterious and huge force, they would have elongagted the holes, no question. If they are looking at holes that seem normal and need a scanning electron microscopes to see if there is any scoring due to the presence of bolts, then there were no bolts.

[lateott]

Another general point:

NTSB disclosed it learned for the first time today that the cockpit door is designed to slam open during rapid decompression.

• Nobody among the flight crew knew about this "feature."
• NTSB shared this with Boeing, and apparently Boeing will make some changes in communication (training)?

Anybody remember the PowerPoint delta training as a marketing feature for the Max to minimize costs of pilot transition? MCAS?