Alaska Airlines 737-900 MAX loses a door in-flight out of PDX
Unfortunately such basic skill failings are showing up in this investigation, be it loose bolts, no locking or poor over sight.
Back years, when I complained as a Licensed Engineer of the poor conditions I had to work under, the 'Gold' 3rd World support exec from Pan Am told me that my job, with enough training, could be done by monkeys, he retired and set up his own Religious Ministry.
Would appear that Boeing have followed his recommendation, but without the training; how tight, basic used to be dictated by the length of a spanner
Back years, when I complained as a Licensed Engineer of the poor conditions I had to work under, the 'Gold' 3rd World support exec from Pan Am told me that my job, with enough training, could be done by monkeys, he retired and set up his own Religious Ministry.
Would appear that Boeing have followed his recommendation, but without the training; how tight, basic used to be dictated by the length of a spanner
I think this last briefing was certainly the worst of the three. However, if you read through the comments of various articles or videos, JH is a big hit with a very large audience. Debbie Hersman would never have tolerated such a clown show but we are operating in a different time.
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This was a "plug" installed in an opening for a semi-plug type door, so the perimeter of the door sits outside for the aircraft. Semi-plug doors swing in from outside, and the latching mechanism lowers the door a few inches to engage the seals and stops.
More interesting, though very hard to discern in the photo, are the roller guides, one of which can be seen with difficulty between the topmost two stops on the side of the door nearest the camera. The NTSB are reporting that both guides are fractured, which opens up the possibility of other failure modes not previously considered.
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The moving part of the hinge stayed on the fuselage. The hinge bracket that accepts the moving pin is there in the picture on one side, it's missing on the other because it severed and is still riding on the hinge pin together with the spring and washers on the fuselage.
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Compelling story from passenger in 25B, the mother of the 15-year old who was in 25A.
"As the air in the passenger cabin rushed out, the Oregon woman turned and saw her son’s seat twisting backward toward the hole, his seat headrest ripped off and sucked into the void, her son’s arms jerked upward. “He and his seat were pulled back and towards the exterior of the plane in the direction of the hole,” she said. “I reached over and grabbed his body and pulled him towards me over the armrest.”
"The woman in the aisle seat of row 25, a stranger to Faye and her son, put on her own mask, then reached across Faye and put the mask on the son. With difficulty, she turned Faye’s head and managed to get a mask on her too. Then she grabbed onto Faye as she in turn kept a tight grip on her son. Faye said she took off her mask so her seatmate could hear her and said “on the count of three I’m going to unbuckle him. We’re going to pull him out.”
"Until then, Faye had seen no flight attendant. As they unbuckled, she reached up and pushed the call button. A flight attendant came to their row. “I saw the shock on her face,” Faye said. “I remember thinking she didn’t know there was a hole in this plane” until that moment."
https://www.seattletimes.com/busines...ht-to-her-son/"The woman in the aisle seat of row 25, a stranger to Faye and her son, put on her own mask, then reached across Faye and put the mask on the son. With difficulty, she turned Faye’s head and managed to get a mask on her too. Then she grabbed onto Faye as she in turn kept a tight grip on her son. Faye said she took off her mask so her seatmate could hear her and said “on the count of three I’m going to unbuckle him. We’re going to pull him out.”
"Until then, Faye had seen no flight attendant. As they unbuckled, she reached up and pushed the call button. A flight attendant came to their row. “I saw the shock on her face,” Faye said. “I remember thinking she didn’t know there was a hole in this plane” until that moment."
Last edited by lateott; 9th Jan 2024 at 15:47. Reason: Typo
More interesting, though very hard to discern in the photo, are the roller guides, one of which can be seen with difficulty between the topmost two stops on the side of the door nearest the camera. The NTSB are reporting that both guides are fractured, which opens up the possibility of other failure modes not previously considered.
Let's assume there is no spacer coaxial with the locking bolt. These locking bolts just need to be "snug" to perform intended function. What if the normal "book" torque was used on the locking bolts nuts when/if they were fitted? I suspect this would squeeze the guide channel subjecting it to loads it was not designed to withstand.
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I had considered a scenario in which improper installation of the upper locking bolts could cause fracture of the guides. I resisted posting until now.
Let's assume there is no spacer coaxial with the locking bolt. These locking bolts just need to be "snug" to perform intended function. What if the normal "book" torque was used on the locking bolts nuts when/if they were fitted? I suspect this would squeeze the guide channel subjecting it to loads it was not designed to withstand.
Let's assume there is no spacer coaxial with the locking bolt. These locking bolts just need to be "snug" to perform intended function. What if the normal "book" torque was used on the locking bolts nuts when/if they were fitted? I suspect this would squeeze the guide channel subjecting it to loads it was not designed to withstand.
I was also thinking that this feature, if indeed this is fact, is too much information!
I had considered a scenario in which improper installation of the upper locking bolts could cause fracture of the guides. I resisted posting until now.
Let's assume there is no spacer coaxial with the locking bolt. These locking bolts just need to be "snug" to perform intended function. What if the normal "book" torque was used on the locking bolts nuts when/if they were fitted? I suspect this would squeeze the guide channel subjecting it to loads it was not designed to withstand.
Let's assume there is no spacer coaxial with the locking bolt. These locking bolts just need to be "snug" to perform intended function. What if the normal "book" torque was used on the locking bolts nuts when/if they were fitted? I suspect this would squeeze the guide channel subjecting it to loads it was not designed to withstand.
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I think that's a very real scenario. The metal casing really isn't very thick and the safety bolt hole takes away more of the substance to the guide. Getting thumped by the roller pin on the upstroke* might just start the casting cracking.
*The paint chipping may well be of a stock photo, but if that is the Alaska aircraft, then the guide just does not have the new look about it you'd expect.
cont.... These locking bolts just need to be "snug" to perform intended function. What if the normal "book" torque was used on the locking bolts nuts when/if they were fitted? I suspect this would squeeze the guide channel subjecting it to loads it was not designed to withstand.
*The paint chipping may well be of a stock photo, but if that is the Alaska aircraft, then the guide just does not have the new look about it you'd expect.
Psychophysiological entity
It's over exposed, but the photo with Bob and Jennifer Homendy shows the one of the guides, and it looks damaged. Not sure.
Oh, I normally don't gush about these things, but super kudos to the mother and the lady that helped them. They've exchanged details. The woman had the presence of mind in the midst of the chaos, to get masks on the boy and mother. The mother also sounds very, very sharp minded.
Oh, I normally don't gush about these things, but super kudos to the mother and the lady that helped them. They've exchanged details. The woman had the presence of mind in the midst of the chaos, to get masks on the boy and mother. The mother also sounds very, very sharp minded.
Last edited by Loose rivets; 9th Jan 2024 at 17:06.
I think that's a very real scenario. The metal casing really isn't very thick and the safety bolt hole takes away more of the substance to the guide. Getting thumped by the roller pin on the upstroke* might just start the casting cracking.
*The paint chipping may well be of a stock photo, but if that is the Alaska aircraft, then the guide just does not have the new look about it you'd expect.
*The paint chipping may well be of a stock photo, but if that is the Alaska aircraft, then the guide just does not have the new look about it you'd expect.
It very much looks as if the distance the door plug needs to lift to clear the stops is less than the distance needed to disengage the rollers from the guides. That wouldn't be a problem in the hangar, but in the air (assuming no bolts fitted) the door would depart as soon as the stops were cleared and while the rollers were still engaged in the guides.
No prizes for guessing what would almost certainly happen to the guides in that scenario,
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IMHO, it is clear that the screws that were supposed to hold the bracket at #2 in the image has come loose, more or less exactly as was about to happen on that United aircraft in the last photo.
From the outside view, it can clearly be seen that the bracket itself has come loose, but is still attached to the hinge. This means that the locking pin is still in place,but it is useless if the bracket itself is loose.
From the inside view, it can also clearly be seen that the bottom part of the aft hinge is intact and attached securely. The spring has been released as lateott pointed out in post 497, but I would argue that the locking pin is still in place, and the problem is that the bracket itself (which holds the locking pin) has come loose.
Once this aft bracket comes loose, it will cause a bad misalignment of the door and eventually it is likely to become shifted vertically. At that point, the front hinge will be ripped out (no bracket remaining there) and the door is gone.
Remarkable that there are no visible locking features on the nuts that are supposed to secure the bracket that holds the actual locking pin for the bottom spring. Obviously the locking pin will become useless if the entire bracket is loose.
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Here is another door plug photo in the backyard, highest resolution and best exposure of the ones I have seen. Unfortunately the guides are obscured.
-stops look fine
-possibly 2 different modes of detachment of the lower hinge brackets from the plug unless there are tricks of light here
-possibly 2 different modes of detachment of the lower hinge brackets from the plug unless there are tricks of light here
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These photos are great and give a very clear picture of the aft hinge.
IMHO, it is clear that the screws that were supposed to hold the bracket at #2 in the image has come loose, more or less exactly as was about to happen on that United aircraft in the last photo.
From the outside view, it can clearly be seen that the bracket itself has come loose, but is still attached to the hinge. This means that the locking pin is still in place,but it is useless if the bracket itself is loose.
From the inside view, it can also clearly be seen that the bottom part of the aft hinge is intact and attached securely. The spring has been released as lateott pointed out in post 497, but I would argue that the locking pin is still in place, and the problem is that the bracket itself (which holds the locking pin) has come loose.
Once this aft bracket comes loose, it will cause a bad misalignment of the door and eventually it is likely to become shifted vertically. At that point, the front hinge will be ripped out (no bracket remaining there) and the door is gone.
Remarkable that there are no visible locking features on the nuts that are supposed to secure the bracket that holds the actual locking pin for the bottom spring. Obviously the locking pin will become useless if the entire bracket is loose.
IMHO, it is clear that the screws that were supposed to hold the bracket at #2 in the image has come loose, more or less exactly as was about to happen on that United aircraft in the last photo.
From the outside view, it can clearly be seen that the bracket itself has come loose, but is still attached to the hinge. This means that the locking pin is still in place,but it is useless if the bracket itself is loose.
From the inside view, it can also clearly be seen that the bottom part of the aft hinge is intact and attached securely. The spring has been released as lateott pointed out in post 497, but I would argue that the locking pin is still in place, and the problem is that the bracket itself (which holds the locking pin) has come loose.
Once this aft bracket comes loose, it will cause a bad misalignment of the door and eventually it is likely to become shifted vertically. At that point, the front hinge will be ripped out (no bracket remaining there) and the door is gone.
Remarkable that there are no visible locking features on the nuts that are supposed to secure the bracket that holds the actual locking pin for the bottom spring. Obviously the locking pin will become useless if the entire bracket is loose.