Don't fly on a 737-MAX

elstoof

United have apparently found a couple of insufficiently tightened door plug bolts in their checks 

stickyfiddle

Honestly right now I would simply avoid airlines with a significant number of 737-MAX frames. Even if they usually don’t use them they can always swap planes around in the day for operational reasons. They’ll almost never use a 737-MAX on a widebody route but one could easily sub in for another 737 or A320

Airlines even occasionally borrow planes from each other, which you can’t account for, but this is generally much rarer 

Teetonetal

elstoof said:

United have apparently found a couple of insufficiently tightened door plug bolts in their checks 

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

Musical_Mystery_Tour

It's true that airlines can use replacement aeroplanes and occasionally do so, but they don't have fleets of spare aeroplanes sat there waiting for such an occasion. There are leasing companies which do have some aeroplanes spare, but it's not a massive number. Aeroplanes do not make money when sat on the ground doing nothing.

Aside from the expanse of leasing a replacement, swapping one aeroplane for another has repercussions which can ripple for a long time as they end up out of position, not at service hubs, and so on. So it's really not a simple case of going and grabbing another one out of the hangar, there just aren't that many spare airliners kicking about. For example,, Norwegian had a fault on a MAX which caused it to divert to Iran in 2018, since the export of spares from the US to Iran was profibited, it took 70 days to get around the issue and the aeroplane was sat there for all that time.

When the type was grounded for twenty months, following the two fatal crashes not long after it entered service, the preceding variant 737 NGs were like gold dust to get hold of as airlines scrambled to try and find suitable stand ins for their shiny new MAXs which they had just paid a lot for but could not use. We had three Norwegian 737 MAX aeroplanes (the MAX launch customer) sat near the end of runway 23L at Manchester for all that time. 

Back with the cause of the issue, it looks to me like they have either not fited the retaining bolts which prevent movement of the door into the down position where it can then swing open, to the door at all, or if they did fit them, then they had not fitted the retaining wire on the nuts, allowing these to shake loose. If those bolts are in place, it should be impossible for the door to move to a position where it can swing open and come off the hinges. With none of those bolts in place, it would allow the retaining lugs on the door to bounce down and out of their locking tracks in turbulence, making it possible for the door to be ejected owing to the pressurisation forcing it open and the springs on the hinges which assist with the movement to push the door into the locking position would then act as an assisting ejector. The only other possible explanation I can think of, would be that the welds for the parts of that retaining system have broken, which seems very unlikely indeed. 

A problem for the investigators will be that if the bolts were fitted and have shaken loose, they should be in the bottom of the fuselage somewhere, but if they got flung out with the door and are not found, it might be difficult to absolutely prove they were there in the first place.

euan

Didn’t the Netflix documentary contain information about how workers making the 737 Max were self certifying their work to save costs?

Kurtis

Kittyfrisk said:

stickyfiddle said:

Can someone please let me know what kind of case this is because I want one??

It's not the case that helped, it's the Gorilla Glass screen protector.
Does what it said on the tin 

How come I put those things on my phone and they manage to break falling off the couch on to the carpet? 

Musical_Mystery_Tour

euan said:

Didn’t the Netflix documentary contain information about how workers making the 737 Max were self certifying their work to save costs?

Yes. There have been a lot of accusations of dodgy practices, but sometimes these are made by people with agendas, so it's not always as simple as it seems. Boeing were indeed found to be colluding with the FAA on the type's certification amongst other things and they basically scapegoated one of the test pilots to mitigate that somewhat, but they were fined a large amont of money in spite of that.

So in the end it would have been far less costly for them to keep everything above board and that's something which is writ large now. They should really have made a new aeroplane type (basically a smaller verion of the 787, which was the original plan) rather than extending the longevity of the venerable 737 by compromising on things in order to compete with the A320 NEO, and I think even Boeing would acknowledge that now given how costly the grounding and other stuff has been for them and the dent in confidence it has gained them.

Everyone who works in aviation can probably tell you some horror story about that kind of thing, and not just at Boeing. But having said that, I would not wish to put people off flying, these incidents make the news of course, which can lead one to think 'oh my god' but it is the fact that they are unusual which makes them newsworthy. I can assure everyone one that as someone who works on aeroplanes every day in my job, myself and my coleagues are extremely concientious and we take our job very seriously indeed. If we think an aeroplane is not safe to go, it ain't moving an inch off that stand. Even regardless of the morality of being that way, it is my signature on the paperwork and either me, or one of my team who is on the cockpit voice recorder saying we've checked it and it is fine, so it is us who would go to prison, not to mention having to live with ourselves for having been to blame for something bad.

JezWynd

menamestom said:

Tannin said:

ICBM said:

 Sadly, unless something very major is turned around and the company culture put back to something like how it was 30 years ago, I don't think Boeing has a good outlook.

If they were a normal commercial business in a competitive market, I'd agree with you.  If this was 30 years ago, Douglas and Lockheed would trample them into the dust. 

But now there is only Boeing. No other company makes large commercial  airplanes (sic). (Foreign companies don't count. Not in the USA.) More to the point, the US relies absolutely on Boeing for the majority of its military aircraft. The company simply cannot and will not be allowed to fail. The US will spend whatever it takes to prop them up, and/or hand them massive sweetheart deals on their military contracts (not for the first time!), and/or figure out ways of banning or taxing competing products (primarily Airbus).

Delta and American Airlines, the 2 biggest airlines in the US are pretty much 50/50 Airbus/Boeing, so I wouldn't say they don't count.  Southwest are all Boeing, United mainly Boeing, but they have Airbus and more on order.

Military, I thought that Lockheed Martin would be the main supplier nowadays?  They make the F-35, which is replacing the now phased out F-18 (out of new orders, not service).  That said, LM subcontract some manufacture to Boeing so this is not to say they are not intrinsically linked.

You're probably right that they won't be allowed to fail, but even in the US, the reliance on Boeng doesn't seem to be quite so absolute.

I’m sure the US govt won’t allow Boeing to fail, the name is closely linked to US vision of American exceptionalism but that doesn’t mean mean that death won’t come via a 1000 cuts as foreign companies look elsewhere for their aircraft. Boeing are a fine example of how America’s hubris is gaining speed.

danishbacon

Boeing inadvertently helping nurture some critical moment stress level increase:

“The cockpit door is designed to open during rapid decompression but no one among the flight crew knew that; they were not informed,” she says.”

Lots more detail here 

https://www.flightglobal.com/safety/guide-roller-fittings-on-alaska-max-9-door-plug-are-fractured-ntsb/156407.article?utm_campaign=FG-INTERNATIONAL-FILLER-090124-DE&utm_medium=email&utm_source=email&utm_content=newsletter

Musical_Mystery_Tour

Think that's to equalise the pressure, but it is handy for hijackers wishing to access the locked cockpit to know that if they pop a round through a nearby window, it'll be open sesame.

Kittyfrisk

Musical_Mystery_Tour said:

Think that's to equalise the pressure, but it is handy for hijackers wishing to access the locked cockpit to know that if they pop a round through a nearby window, it'll be open sesame.

Die Hard, 7-37...

Tannin

You may know Denys Davydov from his invaluable daily updates from Ukraine. Here is today's update: I have come to have a lot of respect for Denys's matter-of-fact, accurate approach, and often learn things from him which the major commercial news sites don't get around to reporting for hours and days later, if at all. 

You may not know that he flies a 737 (or did until his airline was grounded by the war), and he still runs his original You-tube channel, which is aviation-focussed. Today he has produced a video on the Alaska Airlines 737 incident I haven't watched it yet but will with interest. He is a trustworthy reporter and he knows his stuff. 

Danny1969

Another great video with actual footage of the bolts and hinge brackets. The missing bolts are castle nuts and split pins .. they can't come undone so I reckon those bolts were never fitted. 



How can that happen in a safety critical aviation industry ? .. just mind boggling and terrifying to think the biggest operators have brought hundreds of these planes. Ok, all the plug doors on all the planes can be checked but have they left any other bolts out anywhere else. I think all these planes need to be stripped and rebuilt, like do for a plane that's done so many air miles but will be kept in service.  

m_c

From what I've read, the fuselages leave Spirit with the plugs installed, but Boeing are supposed to remove them and then do the final install.
I wonder if Spirit just install them essentially finger tight to seal the fuselage for transport, but then Boeing have not touched them.

I did see a comment somewhere that Spirit had been invited to be part of the NTSB investigation. 

stickyfiddle

Danny1969 said:

Another great video with actual footage of the bolts and hinge brackets. The missing bolts are castle nuts and split pins .. they can't come undone so I reckon those bolts were never fitted. 



How can that happen in a safety critical aviation industry ? .. just mind boggling and terrifying to think the biggest operators have brought hundreds of these planes. Ok, all the plug doors on all the planes can be checked but have they left any other bolts out anywhere else. I think all these planes need to be stripped and rebuilt, like do for a plane that's done so many air miles but will be kept in service.  

My guess is the guys building the planes have too-tight timelines (because capitalism yay) and their managers/foremen have too-tight timelines to check their work properly (because capitalism yayyy), or they've removed too many layers of checks & balances (because capitalism yayyyyyyyyy...)

This stuff always comes back to leadership structuring incentive mechanisms at the top level which filter through to make the product worse. Not a huge issue if you're making tshirts that happen to fall apart a bit less long than last year's version. But a colossal and utterly unforgivable failure when you're talking about planes that carry 200+ people. 

m_c said:

From what I've read, the fuselages leave Spirit with the plugs installed, but Boeing are supposed to remove them and then do the final install.
I wonder if Spirit just install them essentially finger tight to seal the fuselage for transport, but then Boeing have not touched them.

I did see a comment somewhere that Spirit had been invited to be part of the NTSB investigation. 

It's possible that Spirit fitted the nuts but not the pins, I guess? Either way it's Boeing's failure

JezWynd

More detailed info on the door plug mechanism...

https://www.youtube.com/watch?v=maLBGFYl9_o&t=648s

euan

The old adage rings true, never loosely tighten a bolt that you will “do up later”. 

Danny1969

I had my front tyres done once by a place and about 10 mins later driving up the motorway I felt this vibration that got worse and worse so had to pull over. When I come to a juddering stop I jumped out and saw only 2 nuts were left on the nearside and 3 on the offside. All of these were loose. Poxy fitters hadn't torqued them up. I had to nick a couple of nuts from the rear and so all wheels had at least 3 and most 4 nuts 

That plane was originally planned for Hawaii ... the must be one of the longest routes with almost no possible chance of landing in the world. I know they take extra fuel incase they have to do the journey unpressurised but can you imagine flying thousands of miles on a plane with a big hole in the side. I'm not sure they would have made it. 

ICBM

Danny1969 said:

I had my front tyres done once by a place and about 10 mins later driving up the motorway I felt this vibration that got worse and worse so had to pull over. When I come to a juddering stop I jumped out and saw only 2 nuts were left on the nearside and 3 on the offside. All of these were loose. Poxy fitters hadn't torqued them up.

Someone I vaguely know had one of the back wheels literally come off her Volvo for exactly that reason. I can’t remember if she managed to get compensation for the substantial damage to the car.

Haych

Danny1969 said:

How can that happen in a safety critical aviation industry ? 

People!  Humans are fallible.  When you have a chain of humans to produce something then you need process and procedure to ensure they are doing their job properly.

Then add management pushing to get stuff out the door, deadlines to meet and invoices to send etc and those processes and procedures get bypassed and boxes get ticked just to move the thing to the next stage of production.

This isn't the worst incident by a huge margin to ever happen in aviation because higher ups are pushing to meet targets.

You also only need a couple of people in the chain under pressure, stressed, not feeling their best, tired, ill or pissed off and it becomes increasingly easier and easier to find weaknesses in the process for errors to creep in.