Alaska Airlines 737-900 MAX loses a door in-flight out of PDX
Join Date: Nov 2010
Location: Canada
Posts: 133
Likes: 0
Received 0 Likes
on
0 Posts
The door plug has been found! Below is a link to a comprehensive news article including a video of NTSB press conference.
News article with NTSB brief regarding found door plug
News article with NTSB brief regarding found door plug
Ecce Homo! Loquitur...
As an aside…. I’m sure Apple will be all over it for an ad.
Found an iPhone on the side of the road... Still in airplane mode with half a battery and open to a baggage claim for #AlaskaAirlines ASA1282 Survived a 16,000 foot drop perfectly intact!
When I called it in, Zoe at @NTSB said it was the SECOND phone to be found.,,,
Found an iPhone on the side of the road... Still in airplane mode with half a battery and open to a baggage claim for #AlaskaAirlines ASA1282 Survived a 16,000 foot drop perfectly intact!
When I called it in, Zoe at @NTSB said it was the SECOND phone to be found.,,,
Ms Homendy later announced that the part of the fuselage that detached had been found, after a teacher named Bob located the missing section in his yard.
Perhaps the BBC writer or editor noticed something that occurred to me straight away I saw the first quoted version, that it wasn't yet Monday in that part of USA at the time of writing.
We’ll soon know if safety bolts were in place. Without them what prevents door disengaging under negative G and low cabin pressure? Or more likely jiggling loose under a series of reduce G encounters, again with low pressure differential.
Can we all agree that the missing part of the plane is a "door" that replaces an emergency exit "door, That it is NOT a "plug"?, it is not designed as a "plug", does not function as a "plug" under pressurization of the hull. In fact, it performs exactly the opposite. The outward forces work to stress the door against its retainers not the frame in any intrinsic or hermetic manner..
Join Date: Nov 2015
Location: UK
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
So if lowwer bolts missing it's possible that the spring loads caused an upper boult or guide to fail but this seens unlikely to me.
A couple comments:
1) Can we all agree that the missing part of the plane is a "door" that replaces an emergency exit "door, That it is NOT a "plug"?, it is not designed as a "plug", does not function as a "plug" under pressurization of the hull. In fact, it performs exactly the opposite. The outward forces work to stress the door against its retainers not the frame in any intrinsic or hermetic manner..
1) Can we all agree that the missing part of the plane is a "door" that replaces an emergency exit "door, That it is NOT a "plug"?, it is not designed as a "plug", does not function as a "plug" under pressurization of the hull. In fact, it performs exactly the opposite. The outward forces work to stress the door against its retainers not the frame in any intrinsic or hermetic manner..
Join Date: Nov 2015
Location: UK
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
Follow on to my response to JamiaJoe above. I said there should not be significant loads on the quides, pins or upper lock-out bolts.
Unless of course, as I suggested yesterday, the stops were not correctly adjusted. This would put pressurisation loads on the guide / pin possibly resulting in low cycle fatique failure of the guide / pin/ bolt and loss of the plug.
I've seen no comment on this theory.
Unless of course, as I suggested yesterday, the stops were not correctly adjusted. This would put pressurisation loads on the guide / pin possibly resulting in low cycle fatique failure of the guide / pin/ bolt and loss of the plug.
I've seen no comment on this theory.
Join Date: Jan 2024
Location: Cotswolds
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Quite a lot of detail here in a USA NBC account, including a range of comments from the NTSB
Missing door plug that detached from Alaska Airlines plane found in Oregon backyard (nbcnews.com)
Notable is it had pressurisation issues on both the two days before the accident, and although removed from ETOPS as a result, it states "the inspection had not been completed". Which is not surprising because it had been in full all day use every day. The accident flight was right after arrival in Portland from New York. It's also apparent, from the usual "reading between the lines" of accident investigator comments, that they don't like the idea of this sort of door plug at all, and would rather either proper fuselage structure or a proper exit door. Which as it makes its was back to the FAA could lead to some interesting decisions.
Missing door plug that detached from Alaska Airlines plane found in Oregon backyard (nbcnews.com)
Notable is it had pressurisation issues on both the two days before the accident, and although removed from ETOPS as a result, it states "the inspection had not been completed". Which is not surprising because it had been in full all day use every day. The accident flight was right after arrival in Portland from New York. It's also apparent, from the usual "reading between the lines" of accident investigator comments, that they don't like the idea of this sort of door plug at all, and would rather either proper fuselage structure or a proper exit door. Which as it makes its was back to the FAA could lead to some interesting decisions.
Join Date: Sep 2015
Location: UK
Posts: 110
Likes: 0
Received 0 Likes
on
0 Posts
"Jennifer Homendy, chair of the National Transportation Safety Board, said at a news conference that after Alaska Airlines Flight 1282 returned to Portland International Airport, no one pulled the circuit breaker on the cockpit voice recorder or otherwise preserved the audio, which holds only its most recent two hours.
“The cockpit voice recorder was completely overwritten. There was nothing on the cockpit voice recorder,” Homendy said."
"The NTSB chief revealed that Alaska Airlines had blocked the plane from being used on flights to and from Hawaii because of a warning light that had lighted up at least three times, possibly indicating a pressurization problem on the aircraft.
The warning light had turned on during flights on Dec. 7, Jan. 3 and Jan. 4, and each time, maintenance crews tested and then reset the light.
“We don’t know that there was any correlation” between the warning lights and what happened during Friday night’s flight, Homendy said. But Alaska Airlines had restricted that jet from transcontinental routes so that the plane could return to an airport during an emergency, she said.
Because the pressurization light had gone off several times, additional maintenance was ordered on the plane, but it had not yet been performed before Friday’s flight."
(Source: https://www.latimes.com/california/s...warning-lights)
CVR
What a shame the CVR data was over-written. Does AS have an SOP for data preservation? If not, why not? I appreciate this crew had just been put through the wringer and it might not have been top of their agenda, but that’s why an SOP is important.
Interesting to see that an explosive decompression that was violent enough to blow open the flight deck door and remove the FO’s headset wasn’t sufficiently violent to warrant the use of ’Mayday’.
Interesting to see that an explosive decompression that was violent enough to blow open the flight deck door and remove the FO’s headset wasn’t sufficiently violent to warrant the use of ’Mayday’.
Join Date: Jan 2024
Location: Cotswolds
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
If correctly installed this door plug should never ever move.
Given the amount of differential pressure acting upon it at cruising altitude (~8psi) these considerable forces should be taken up by fixed stop pads- giving a mechanical face-to-face contact between the plug & the surrounding fuselage.
In any normal circumstances the amount of differential pressure acting on a regular cabin door will lock it totally solid in flight. You cannot physically open a door using the internal handle at altitude with the jet pressurised as you cannot overcome these forces.
From the images there would appear to be 6 bolts per side installed at manufacture which additionally hold the plug in position vertically & horizontally. These shouldn’t take any of the pressurisation loads however.
Given the low cycles of the airframe I would be very surprised if fatigue is a factor.
With previous potential indication &/or pressurisation issues &/or possible work carried out in that area then there is potential for human interaction/error. All conjecture of course.
The problem with any of these plugs is that they are filling a gap in the fuselage that was originally meant to contain a door. Whilst they are generally a fit & forget solution at manufacture- they are removable.
The only saving grace from this incident is that the incident appears to have happened at less than full diff px- thus the explosive nature has been somewhat reduced. If it had happened in the cruise there would have been a much higher probability of a more forceful depressurisation involving seats & passengers and far greater damage such as happened in historic cases.
Given the amount of differential pressure acting upon it at cruising altitude (~8psi) these considerable forces should be taken up by fixed stop pads- giving a mechanical face-to-face contact between the plug & the surrounding fuselage.
In any normal circumstances the amount of differential pressure acting on a regular cabin door will lock it totally solid in flight. You cannot physically open a door using the internal handle at altitude with the jet pressurised as you cannot overcome these forces.
From the images there would appear to be 6 bolts per side installed at manufacture which additionally hold the plug in position vertically & horizontally. These shouldn’t take any of the pressurisation loads however.
Given the low cycles of the airframe I would be very surprised if fatigue is a factor.
With previous potential indication &/or pressurisation issues &/or possible work carried out in that area then there is potential for human interaction/error. All conjecture of course.
The problem with any of these plugs is that they are filling a gap in the fuselage that was originally meant to contain a door. Whilst they are generally a fit & forget solution at manufacture- they are removable.
The only saving grace from this incident is that the incident appears to have happened at less than full diff px- thus the explosive nature has been somewhat reduced. If it had happened in the cruise there would have been a much higher probability of a more forceful depressurisation involving seats & passengers and far greater damage such as happened in historic cases.
2) a) Photos of one guide pin on the accident plane appear to show a very short length of the guide pin/roller. Its length significantly less than its diameter. b) The dummy door (not a PLUG) differs from an Emergency Exit Door (not a PLUG) in a significant way. The cross bracing is removed to accommodate a larger window. Could the combination of the panel being weaker at that point have allowed the door (not a PLUG) to bow outward and dislodged the upper portion of the door from the guide pins/rollers? The four rigging bolts would do little to retain the door at this point.
What a shame the CVR data was over-written. Does AS have an SOP for data preservation? If not, why not? I appreciate this crew had just been put through the wringer and it might not have been top of their agenda, but that’s why an SOP is important.
Interesting to see that an explosive decompression that was violent enough to blow open the flight deck door and remove the FO’s headset wasn’t sufficiently violent to warrant the use of ’Mayday’.
Interesting to see that an explosive decompression that was violent enough to blow open the flight deck door and remove the FO’s headset wasn’t sufficiently violent to warrant the use of ’Mayday’.
What a shame the CVR data was over-written. Does AS have an SOP for data preservation? If not, why not? I appreciate this crew had just been put through the wringer and it might not have been top of their agenda, but that’s why an SOP is important.
Interesting to see that an explosive decompression that was violent enough to blow open the flight deck door and remove the FO’s headset wasn’t sufficiently violent to warrant the use of ’Mayday’.
Interesting to see that an explosive decompression that was violent enough to blow open the flight deck door and remove the FO’s headset wasn’t sufficiently violent to warrant the use of ’Mayday’.
One day the CVR industry will come up with an ever so simple way to avoid this overwriting. Goodness knows how often it has occurred in incidents in the past. I know the requirement is to maintain the last 2 hours, but that didn't extend to any instruction to start overwriting at 2 hours and 1 minute.
Except that I would think something that shape could possibly lose forward momentum quite quickly if tumbling, so that its trajectory quickly becomes more vertical and therefore the radial speed falls below the threshold of Moving Target Indicator (MTI) suppression speed (used to eliminate clutter). If it did paint initially, I suspect it would fade pretty quickly.
Anyway, they found the door, so, on to the next bit!
Originally Posted by JamaicaJoe
I think the guide roller on at least the side shown in photos was not long enough to reliably engage the door. The four bolts really do nothing to secure the door , rather prevent movement of the mechanism.
Join Date: Jul 2008
Location: MA, USA
Age: 54
Posts: 76
Likes: 0
Received 0 Likes
on
0 Posts
AIUI they still had the QRH, just the laminated checklist card went for a jaunt.