Garfly Posted January 8 Share Posted January 8 1 Link to comment Share on other sites More sharing options...
facthunter Posted January 9 Share Posted January 9 Very small dia bolt to be doing that job. Why wouldn't it bend and allow some free movement? Nev Link to comment Share on other sites More sharing options...
octave Posted January 9 Share Posted January 9 1 Link to comment Share on other sites More sharing options...
facthunter Posted January 9 Share Posted January 9 No that one's already taken by a VN Commodore with one wheel on the kerb.. Nev 1 Link to comment Share on other sites More sharing options...
Garfly Posted January 9 Share Posted January 9 Inspections turn up more loose bolts: 1 Link to comment Share on other sites More sharing options...
turboplanner Posted January 9 Share Posted January 9 What the fuss? The door was found in a garden. It's fine, ready to go back in. 1 Link to comment Share on other sites More sharing options...
onetrack Posted January 9 Share Posted January 9 I saw an interview with a NTSB senior woman manager and she was at pains to point out that there was an indication of confusion between cabin crew and flight crew, with the flight crew apparently unable to gain correct or accurate information from the cabin crew, as to "what was happening down the back?". As a result, the NTSB was keen to acquire the CVR record, so they could determine where the communication problems were, and whether there were possibilities that this communication difficulty could be another B737 MAX problem that needed to be addressed. 1 Link to comment Share on other sites More sharing options...
kgwilson Posted January 9 Share Posted January 9 If the bolts have been found to be loose on other Max-9s, either they were not tightened sufficiently when installed or there is no split pin in the castle nut. If the split pin is there a castle nut can't unwind. 2 Link to comment Share on other sites More sharing options...
Garfly Posted January 9 Share Posted January 9 38 minutes ago, turboplanner said: What the fuss? The door was found in a garden. 6 Link to comment Share on other sites More sharing options...
facthunter Posted January 9 Share Posted January 9 That SMALL bolt can bend. It's not in sheer. It's against a cylindrical SURFACE. Once it bends there's play, and it can rattle around in a heavy landing etc. Nev 1 Link to comment Share on other sites More sharing options...
aro Posted January 9 Share Posted January 9 The small bolt isn't carrying weight. It is acting as a pin to prevent the door from being lifted. The bolt is going through the piece attached to the door. Link to comment Share on other sites More sharing options...
facthunter Posted January 9 Share Posted January 9 I suggest you look at it in more detail and listen to the "usual" bloke explaining how it works. IT holds the door DOWN so the stops are doing their job and staying on alignment. IF the door (or Fuselage) distorts and/or moves UP, it's all over. Nothing to stop it falling away. Nev Link to comment Share on other sites More sharing options...
aro Posted January 9 Share Posted January 9 1 hour ago, facthunter said: Once it bends there's play, and it can rattle around in a heavy landing etc But why would it bend? You would need to lift the door to bend the bolt, and you're working against gravity, landing loads (i.e. positive G) etc. It is a larger version of a cotter pin, i.e. preventing movement but not taking the load. Link to comment Share on other sites More sharing options...
facthunter Posted January 9 Share Posted January 9 It wouldn't work as a cotter pin. It's NOT supported by being in a hole. Everything moves on an aeroplane The Pads the door sits on are not large . Just listen to the bloke I referred you to and I'll carry on from there if necessary. Nev Link to comment Share on other sites More sharing options...
aro Posted January 9 Share Posted January 9 6 hours ago, Garfly said: 14 minutes ago, facthunter said: It wouldn't work as a cotter pin. It's NOT supported by being in a hole. Everything moves on an aeroplane The Pads the door sits on are not large . Just listen to the bloke I referred you to and I'll carry on from there if necessary. Nev See the video above from about the 7 minute mark. Are they the bolts you are referring to? Link to comment Share on other sites More sharing options...
facthunter Posted January 9 Share Posted January 9 Yes. Nev Link to comment Share on other sites More sharing options...
kgwilson Posted January 9 Share Posted January 9 Juan Browne flys for American Airlines and his own Luscombe. His Youtube Channel Bancolirio is pretty informative but he does give credit to the expertise of others where required. Interestingly the best and most technically proficient individual regarding Boeing 737s of all models is an Englishman & 737 Captain Chris Brady who has the Boeing 737 Technical channel on Youtube. https://www.youtube.com/channel/UCdjozru7tpmCMePCESlcZsw 1 Link to comment Share on other sites More sharing options...
kgwilson Posted January 9 Share Posted January 9 I just read that an aircraft technician with 23 years experience whose company operates Max-9s and has this to say I've been an aircraft technician for 23 years and we operate the Max9. I’ve opened and closed one of these plugs as well. Keep in mind that other 737 NG’s have these plugs installed in the longer fuselage models, not just the Max. They all work the same way and there’s never been an incident like this. I’m not saying this is what happened, but I can’t see how this could lug could come loose unless the two upper capture bolts, and the two lower bolts through the spring hinges weren’t installed. Even if a set of bolts, either uppers or lowers were missing with the opposites installed, I can’t see how the plug could come loose and depart the airframe. Just my ten cents. To open the plugs, the corresponding row of seats where it’s located has to be removed, and the surrounding interior side wall paneling and insulation. There’s also a seal that reacts to ambient temp that helps keep everything nice and tight. If they find the bolts were never installed that will be another nail in the Boeing coffin. 3 Link to comment Share on other sites More sharing options...
facthunter Posted January 9 Share Posted January 9 I don't find that contribution very convincing. I've opened and closed ONE of these plugs as well?? and how much stuff has to be moved to get at it has nothing to do with anything.. Nev Link to comment Share on other sites More sharing options...
Garfly Posted January 9 Share Posted January 9 (edited) On 07/01/2024 at 12:18 PM, Garfly said: This is a tech explanation of the various 737 mid-cabin doors/plugs configs. The Alaskan incident is referred to near the end (21:45). This is another educated guess coming from the Comments Section of this Capt. Brady video. : @USAmerican100 2 days ago (edited) As an Aerospace Engineer, my "guess" is the lower hinge bolts were not installed properly. It looks like they are in an out-of-the-way, hard to see location. Could have been overlooked during a demanding work day. So as the plane climbs to altitude air pressure pushes out on the door, and it bends the door outward slightly. The lower hinge sliders move up slightly due to this bending. All of the upwards loads are now being taken by the two upper bolts. After a few dozen flights/cycles, those two overloaded upper bolts fail and allow the door to pop up and off. Edited January 9 by Garfly 1 Link to comment Share on other sites More sharing options...
aro Posted January 9 Share Posted January 9 Looking at the descriptions, I can't see how it could happen unless the guide track itself wasn't attached to the door properly. It will be interesting to see what they find from examining the door... 1 Link to comment Share on other sites More sharing options...
facthunter Posted January 9 Share Posted January 9 Except the Diff pressure at 16,000 ft was no where near max diff where it would have done on all previous flights. Had this gone all the way to cruising flight level it would have been another story entirely. Nev Link to comment Share on other sites More sharing options...
facthunter Posted January 9 Share Posted January 9 There's no actual Guide track. The door sits on stops down both sides which are of fairly limited area. Once it moves a bit, things start to go bad quickly. It's TESTED static at 1.5 max diff. after installation.. Nev Link to comment Share on other sites More sharing options...
Blueadventures Posted January 9 Share Posted January 9 57 minutes ago, facthunter said: There's no actual Guide track. The door sits on stops down both sides which are of fairly limited area. Once it moves a bit, things start to go bad quickly. It's TESTED static at 1.5 max diff. after installation.. Nev The plug doors I have used on Cessnas are fitted from inside. I would remove when in the drop zone so rafts and food packs etc could be pushed out to drop to stricken vessels etc. They are safer as long as not dropped out the opening although they had wires attached to prevent such. 59 minutes ago, facthunter said: There's no actual Guide track. The door sits on stops down both sides which are of fairly limited area. Once it moves a bit, things start to go bad quickly. It's TESTED static at 1.5 max diff. after installation.. Nev 1 Link to comment Share on other sites More sharing options...
red750 Posted January 9 Author Share Posted January 9 I see where they found some mobile phones which fell from the plane and they were still working. 1 Link to comment Share on other sites More sharing options...
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