Author Topic: Boeing 737 Max again, it would be nice if the windows [door plugs] stayed in!  (Read 97646 times)

0 Members and 1 Guest are viewing this topic.

Offline pickle9000

  • Super Contributor
  • ***
  • Posts: 2439
  • Country: ca
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #50 on: January 08, 2024, 01:21:53 am »
Found this apparently same type but looks to be other side. Not from the Alaska plane.
 

Offline Andy Chee

  • Frequent Contributor
  • **
  • Posts: 773
  • Country: au
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #51 on: January 08, 2024, 08:04:01 am »
Looks like the door plug has been recovered.

« Last Edit: January 08, 2024, 08:21:58 am by Andy Chee »
 

Offline tom66

  • Super Contributor
  • ***
  • Posts: 6810
  • Country: gb
  • Electronics Hobbyist & FPGA/Embedded Systems EE
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #52 on: January 08, 2024, 09:37:12 am »
NTSB also confirming ETOPS certification was suspended due to pressurisation warnings. 
 

Offline AndyBeez

  • Frequent Contributor
  • **
  • Posts: 856
  • Country: nu
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #53 on: January 08, 2024, 09:49:00 am »
Door found. Plus, proof that you CAN drop your phone out of a plane and it will survive the fall.
https://abc7.com/alaska-airlines-door-plug-blows-off-boeing-737-max-9-oregon-flight/14294292/
 

Offline GyroTopic starter

  • Super Contributor
  • ***
  • Posts: 9740
  • Country: gb
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #54 on: January 08, 2024, 10:10:48 am »
Looking at the outside view in the video in Reply #27, those appear to be the two hinge pins sticking out horizontally. The front one is clean - minus the big guide retaining (travel limiting) washer and locknuts. The rear one appears to still have something still attached to it - the remains of the hinge guide ripped from the door?

One of long bits at the bottom is probably the spring that carries the weight of the door so it can be delatched..

Looking at the Boeing video, there was a spring on both hinge pins, I can't see anything to show that they are captive though.


When the door/plug opened it would have immediately been hit by a 400MPH sideways blast. The movement on the front pin would have been a bit more linear (pivoting on the rear one) so the hinge guide probably hit the end of the front pin with a lot of force. That might have been enough to knock off the washer and locknuts. With the front pin disengaged, the twisting motion on the rear pin would probably have been enough to rip the rear hinge guide off the door, leaving the apparent remnants still attached to it.

Now that they've found the door (in somebody's yard according to the BBC) there ought to be plenty of telltale evidence. I suppose it's always possible that, if the door had been removed for access, the hinge pin end washers and locknuts might have been left off as well as the locking bolts. A examination of the front hinge pin end with answer that one, it will either have snapped or stripped threads, or intact ones.

In terms of whether the door should have stayed with the plane, that's a tricky one. On the one hand, it coming off could easily have damaged the rear flight surfaces. On the other hand having a non aerodynamic door crashing up and down in the air blast might have had a tin-opener effect on the bottom of the airframe via the hinge pin mounts. It's not as if anyone was going to be able to close it again.  I'd be surprise if there isn't distortion around the hinge pin mounts on the airframe anyway.


P.S. Looking at the BBC report again, the decompression was enough to rip open the cockpit door and suck out the co-pilots clipboard and headset. If that happened at 16000ft, it doesn't sound good in terms of helping the pilots retain control during a sudden depressurization even. Surely the (anti-hijack?) door ought to be strong enough to let the cockpit depressurize in a slower and more controlled fashion.

https://www.bbc.co.uk/news/world-us-canada-67909417

(There's also further indication that the plane has shown decompression warnings on previous flights and had been withdrawn from routes over water! [Ed: as tom66 indicated])
« Last Edit: January 08, 2024, 10:32:21 am by Gyro »
Best Regards, Chris
 
The following users thanked this post: pickle9000

Offline tom66

  • Super Contributor
  • ***
  • Posts: 6810
  • Country: gb
  • Electronics Hobbyist & FPGA/Embedded Systems EE
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #55 on: January 08, 2024, 11:30:27 am »
Apparently, someone's iPhone survived the fall from 16,000 ft.  Quite impressive, though I guess if it just landed in a bush it may have absorbed the blow nicely.

https://twitter.com/SeanSafyre/status/1744138937239822685

(Also, please people, set your phones to lock after a short period of time.  A random stranger shouldn't be able to read your emails, even if you didn't expect your phone to be blown out of an aircraft.)
 

Offline GyroTopic starter

  • Super Contributor
  • ***
  • Posts: 9740
  • Country: gb
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #56 on: January 08, 2024, 01:00:31 pm »
Apparently, someone's iPhone survived the fall from 16,000 ft.  Quite impressive, though I guess if it just landed in a bush it may have absorbed the blow nicely.

Maybe Apple slowed it down. :D   https://www.bbc.co.uk/news/technology-67911517
Best Regards, Chris
 
The following users thanked this post: AndyBeez

Offline Jeroen3

  • Super Contributor
  • ***
  • Posts: 4090
  • Country: nl
  • Embedded Engineer
    • jeroen3.nl
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #57 on: January 08, 2024, 01:32:02 pm »
 

Online SiliconWizard

  • Super Contributor
  • ***
  • Posts: 14892
  • Country: fr
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #58 on: January 08, 2024, 08:05:54 pm »
Boeing has lost more than a door I guess.
 

Offline pickle9000

  • Super Contributor
  • ***
  • Posts: 2439
  • Country: ca
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #59 on: January 08, 2024, 08:28:59 pm »
Looking at the outside view in the video in Reply #27, those appear to be the two hinge pins sticking out horizontally. The front one is clean - minus the big guide retaining (travel limiting) washer and locknuts. The rear one appears to still have something still attached to it - the remains of the hinge guide ripped from the door?

One of long bits at the bottom is probably the spring that carries the weight of the door so it can be delatched..

Looking at the Boeing video, there was a spring on both hinge pins, I can't see anything to show that they are captive though.


When the door/plug opened it would have immediately been hit by a 400MPH sideways blast. The movement on the front pin would have been a bit more linear (pivoting on the rear one) so the hinge guide probably hit the end of the front pin with a lot of force. That might have been enough to knock off the washer and locknuts. With the front pin disengaged, the twisting motion on the rear pin would probably have been enough to rip the rear hinge guide off the door, leaving the apparent remnants still attached to it.

Now that they've found the door (in somebody's yard according to the BBC) there ought to be plenty of telltale evidence. I suppose it's always possible that, if the door had been removed for access, the hinge pin end washers and locknuts might have been left off as well as the locking bolts. A examination of the front hinge pin end with answer that one, it will either have snapped or stripped threads, or intact ones.

In terms of whether the door should have stayed with the plane, that's a tricky one. On the one hand, it coming off could easily have damaged the rear flight surfaces. On the other hand having a non aerodynamic door crashing up and down in the air blast might have had a tin-opener effect on the bottom of the airframe via the hinge pin mounts. It's not as if anyone was going to be able to close it again.  I'd be surprise if there isn't distortion around the hinge pin mounts on the airframe anyway.


P.S. Looking at the BBC report again, the decompression was enough to rip open the cockpit door and suck out the co-pilots clipboard and headset. If that happened at 16000ft, it doesn't sound good in terms of helping the pilots retain control during a sudden depressurization even. Surely the (anti-hijack?) door ought to be strong enough to let the cockpit depressurize in a slower and more controlled fashion.

https://www.bbc.co.uk/news/world-us-canada-67909417

(There's also further indication that the plane has shown decompression warnings on previous flights and had been withdrawn from routes over water! [Ed: as tom66 indicated])

Wow super interesting.
 

Offline tom66

  • Super Contributor
  • ***
  • Posts: 6810
  • Country: gb
  • Electronics Hobbyist & FPGA/Embedded Systems EE
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #60 on: January 08, 2024, 09:33:50 pm »
United Airlines finds bolts needed "tightening" on "some" Boeing 737-9's.

https://www.bbc.co.uk/news/world-us-canada-67919436

I wonder how many other bolts on the aircraft need "tightening".  Boeing QC is epic.

 

Offline GyroTopic starter

  • Super Contributor
  • ***
  • Posts: 9740
  • Country: gb
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #61 on: January 08, 2024, 10:25:49 pm »
Quote
In its statement, United said: "Since we began preliminary inspections on Saturday, we have found instances that appear to relate to installation issues in the door plug - for example, bolts that needed additional tightening."

Hmm, the inclusion of "- for example" in the UA statement seems rather suspicious, especially as the bolts and (castellated) nuts that block the unlatching movement are clearly secured from coming apart by split pins (from the Boeing video [Edit: Reply #37]).

I suspect that some other 'examples' might include 'nothing there to tighten' and 'they forgot to fit the split pins'!
« Last Edit: January 08, 2024, 10:33:07 pm by Gyro »
Best Regards, Chris
 
The following users thanked this post: amyk

Offline floobydust

  • Super Contributor
  • ***
  • Posts: 7197
  • Country: ca
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #62 on: January 08, 2024, 11:09:18 pm »
The CEO David Calhoun needs to go out the door. Actually their board is a clown fest.
$1.4M pay and $22.5M compensation in 2022. He lost a $7M bonus because of 777X delays. His last one, $5.3M to stick around, retention grant.
His degree is in accounting FFS, he worked for investment firm Blackstone.

Imagine taking a few million less in pay and bonus, hiring more top notch qualified people to work on restoring the company?
Greed is good, greed is legal but I guess it doesn't matter if the ride comes to an end - you made millions like Muilenburg did. Party on.

If United Airlines is seeing faults, then it's systemic and Boeing can't spin it as a one-of. Stock down -8% so BUY BUY BUY  >:D
edit: Spirit AeroSystems stock down -11% so BUY BUY BUY  >:D
« Last Edit: January 09, 2024, 03:24:30 am by floobydust »
 

Offline bdunham7

  • Super Contributor
  • ***
  • Posts: 7969
  • Country: us
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #63 on: January 08, 2024, 11:20:06 pm »
I suspect that some other 'examples' might include 'nothing there to tighten' and 'they forgot to fit the split pins'!

One of the things that can cause a bolt to "need tightening" is if the structure that it is clamping has collapsed or shifted in some way.  This can be as simple as shavings, grit or random crap caught in between surfaces or ti can be a more complex issue like fretting due to movement.  Either way, there should be a revised inspection schedule to examine these parts much more often until they actually know the cause.  Simply concluding that peope have been neglecting to torque the bolts would be simplistic and premature.
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Offline floobydust

  • Super Contributor
  • ***
  • Posts: 7197
  • Country: ca
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #64 on: January 08, 2024, 11:36:46 pm »
There's an old adage "you can't inspect-in quality", from W. Edwards Deming I think. No amount of inspection ensures a quality product.

It appears everything hardware-wise is the same on these doors except the plug has the locking fasteners, they have cotter pins. I have used Loctite (red 271 permanent) on products on semi trucks with high vibration.
 

Offline tggzzz

  • Super Contributor
  • ***
  • Posts: 19995
  • Country: gb
  • Numbers, not adjectives
    • Having fun doing more, with less
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #65 on: January 08, 2024, 11:45:52 pm »
More information
https://theaircurrent.com/feed/dispatches/united-finds-loose-bolts-on-plug-doors-during-737-max-9-inspections/

Multiple aircraft, multiple locations, multiple sub-optimalities.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline BrianHG

  • Super Contributor
  • ***
  • Posts: 7856
  • Country: ca
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #66 on: January 08, 2024, 11:50:13 pm »
Lost door found:


 

Offline AndyBeez

  • Frequent Contributor
  • **
  • Posts: 856
  • Country: nu
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #67 on: January 09, 2024, 12:04:34 am »
I guess something has to fall off in the shake down period.. but, I might expect this random assembly skilset from a DIYer who does the odd flat pack on weekends, but not from airframe fitters who do this as their day job. There is a serious QC fail in the supply chain. Always C check your brand new Boeing plane, even if it's under warranty.
 

Offline pickle9000

  • Super Contributor
  • ***
  • Posts: 2439
  • Country: ca
 

Offline pickle9000

  • Super Contributor
  • ***
  • Posts: 2439
  • Country: ca
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #69 on: January 09, 2024, 12:15:54 am »
Lower hinge mount to door, upper bolts found loose as well but not on this aircraft.
 

Online coromonadalix

  • Super Contributor
  • ***
  • Posts: 6219
  • Country: ca
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #70 on: January 09, 2024, 12:32:48 am »
wow  they really play with our lives ...
 

Offline Andy Chee

  • Frequent Contributor
  • **
  • Posts: 773
  • Country: au
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #71 on: January 09, 2024, 12:50:47 am »
wow  they really play with our lives ...
Well airline carrier insurance companies do place a price on human life.

Evidently cutting costs in quality control is worth more to Boeing than the insurance payout.....
 

Offline pickle9000

  • Super Contributor
  • ***
  • Posts: 2439
  • Country: ca
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #72 on: January 09, 2024, 12:58:54 am »
Keep in mind the design is old, that's crazy. Very lucky in terms of life.
 

Offline jonpaul

  • Super Contributor
  • ***
  • Posts: 3492
  • Country: fr
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #73 on: January 09, 2024, 01:06:50 am »
Latest news: Prelim examination of other aircraft reveals improperly tightened door seal bolts

Jon
Jean-Paul  the Internet Dinosaur
 

Offline pickle9000

  • Super Contributor
  • ***
  • Posts: 2439
  • Country: ca
Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #74 on: January 09, 2024, 01:09:14 am »
It sounds like the door shook loose mispositioned at ground level and was ready to go during the climb. Under pressure as long
as it's aligned it should stay put.

 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf