Boeing Keep your seatbelt low and tight in flight, especially when seated next to a plugged door

[Vanadium 50]

Can they just check all the aircraft bolts for tightness please

They have grounded these planes already. This is causing major disruptions.

However, depending on the problem, maybe they will find it, and maybe they won't. If the bolts are bad, but correctly installed, that's a harder problem to catch than if they were installed correctly.

 

[berkeman]

Can they just check all the aircraft bolts for tightness please

'Scuse me mam, just checking your bolts here today. Okay, you're good. Have a nice flight.

 

[Vanadium 50]

Is not plug door. Is door plug.

As far as being restricted from flying over water, would you feel better if it weren't so restricted?

I flew on a 777s first flight with passengers. ORD-CDG. There were still bits of plastic covering various things, like the TV controls. Not sure how I felt about being over an ocean on a brand new plane.

 

[berkeman]

I flew on a 777s first flight with passengers. ORD-CDG. There were still bits of plastic covering various things, like the TV controls. Not sure how I felt about being over an ocean on a brand new plane.

Did you pay extra for that?

 

[Greg Bernhardt]

As far as being restricted from flying over water, would you feel better if it weren't so restricted?

I'd feel better if they'd take it out of service and get it air worthy. If they are so nervous about getting to an airport in time, it aint air worthy.

 

[Vanadium 50]

I'd feel better if they'd take it out of service and get it air worthy.

How is this possible?

One can say "We want 500 hours (or whatever) of overland flying before we take it over the ocean." I think that may even be reasonable. But you can't say "We want 500 hours of overland flying before we take it over the land."

Every US aircraft with that plug is out of service pending inspection. What more do you want?

 

[DaveE]

Alaska and United Airlines found loose bolts on the door plugs on several of its grounded 737 Max 9 planes days after a door plug blew out of an Alaska Airlines plane while it was in-flight.

https://www.seattletimes.com/busine...olts-on-door-plug-when-inspecting-its-max-9s/

Also, Juan Browne reported that Boeing removes and reinstalls the door plug after they receive the fuselage from Spirit to install the aircraft interior.

 

[Tom.G]

Sounds like a case of RTFM.

"Read the fuc**ng err, fine, manual!"

 

[russ_watters]

How is this possible?

One can say "We want 500 hours (or whatever) of overland flying before we take it over the ocean." I think that may even be reasonable. But you can't say "We want 500 hours of overland flying before we take it over the land."

Every US aircraft with that plug is out of service pending inspection. What more do you want?

Passengers. It's about the passengers.

 

[nsaspook]

Bob has his 15 min of fame.

 

[Greg Bernhardt]

Every US aircraft with that plug is out of service pending inspection. What more do you want?

How about inspected before the door blows off in flight if they were so nervous?

 

[Borg]

It's like opportunity.

 

[Vanadium 50]

How about inspected before the door blows off in flight if they were so nervous?

It's not a door. It's a plug.

It surely was inspected. Somewhere there is some paperwork which states how tight the fasteners. Clearly that wasn't enough.

Would more inspections help? Maybe, ,maybe not. Depends on what the problem was - were the bolts too loose? Or were they too fragile? Or is there something else: say a resonance issue causing them to work their way loose. I am unsure that doing more of what didn't work in this case is the solution.

It's also worth pointing out that taking these planes out of service is causing passengers to seek alternatives. Alaska flies about 40 billion passenger-miles per year, and driving kills about 5 people per billion passenger miles. So while they are flying, they save about 200 lives a year. If they lose 40% of their capacity for a week, the expectation value of fatalities due to alternative transportation approaches 1. And that's just Alaska.

I'm not suggesting ignoring the issue. But I am pointing out that overreacting also has its costs.

 

[difalcojr]

Bolting a plug? With all that wind pressure and vibration?! Think of bridges.

 

[gmax137]

"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," United said in a statement..."

The bolt physically traps the guide roller, preventing it from moving "down" in the track. Looks like it will perform this function regardless of how "tight" it is -- as long as it is present. Were they even present? Or maybe the cotter pins were missing and the castle nut vibrated off, and then the bolt escaped. All four of them.

 

[berkeman]

Alaska and United Airlines found loose bolts on the door plugs on several of its grounded 737 Max 9 planes days after a door plug blew out of an Alaska Airlines plane while it was in-flight.

https://www.seattletimes.com/busine...olts-on-door-plug-when-inspecting-its-max-9s/

Also, Juan Browne reported that Boeing removes and reinstalls the door plug after they receive the fuselage from Spirit to install the aircraft interior.

Great video, thanks @DaveE

And "loose bolts"? The Cotter pins would have to have been missing for that to happen, no? I suppose if Boeing reused the Cotter pins after the reinstallation, they could have failed and allowed the nuts to back off, but I can't imagine the technicians reusing Cotter pins.

@Flyboy -- You aren't allowed to reuse Cotter pins during maintenance, right?

 

[nsaspook]

Great video, thanks @DaveE

And "loose bolts"? The Cotter pins would have to have been missing for that to happen, no? I suppose if Boeing reused the Cotter pins after the reinstallation, they could have failed and allowed the nuts to back off, but I can't imagine the technicians reusing Cotter pins.

@Flyboy -- You aren't allowed to reuse Cotter pins during maintenance, right?

No, never.

You use a bent nail instead.

 

[Vanadium 50]

Or maybe the cotter pins were missing

When they replace them, it will be "Welcome back, Cotter."

 

[russ_watters]

And "loose bolts"? The Cotter pins would have to have been missing for that to happen, no? I suppose if Boeing reused the Cotter pins after the reinstallation, they could have failed and allowed the nuts to back off....

This is what caused my in-flight incident...

 

[berkeman]

This is what caused my in-flight incident...

I missed the memo, but am glad you are still with us...

 

[Flyboy]

Great video, thanks @DaveE

And "loose bolts"? The Cotter pins would have to have been missing for that to happen, no? I suppose if Boeing reused the Cotter pins after the reinstallation, they could have failed and allowed the nuts to back off, but I can't imagine the technicians reusing Cotter pins.

@Flyboy -- You aren't allowed to reuse Cotter pins during maintenance, right?

You are correct on both fronts. You never, EVER reuse cotter pins because of the risk of fatigue failures. They're like a penny a piece, why not get a fresh one?
That said, I've seen cotter pins fail from other, non-reuse causes, too. Had one let go on a throttle linkage on a business jet a few months back. We knew it had been installed because two separate people looked at it before we cowled it up and sent it, and when it came back it was gone. Best we could figure was that it was just a bad pin and it cracked loose, but we could never prove it.

We scrapped that entire batch of cotter pins out of an abundance of caution after that.

No, never.
View attachment 338346
You use a bent nail instead.

... I swear to god I will murder someone if I caught them doing stuff like that.

 

[russ_watters]

I missed the memo, but am glad you are still with us...

My "stuck" throttle this spring: https://www.physicsforums.com/threads/my-in-flight-incident.1058960/

 

[russ_watters]

As far as being restricted from flying over water, would you feel better if it weren't so restricted?

I'd feel better if they'd take it out of service and get it air worthy. If they are so nervous about getting to an airport in time, it aint air worthy.

One can say "We want 500 hours (or whatever) of overland flying before we take it over the ocean." I think that may even be reasonable. But you can't say "We want 500 hours of overland flying before we take it over the land." ...What more do you want?

Passengers. It's about the passengers.

We'll see if this failure was related to the pressurization system errors, but if so, the plane was in service for a little less than a month or perhaps 250 flight hours before the problem manifested that eventually resulted in this incident. There's a set of flight tests performed that lasts a certain number of hours, in a "shakedown" period before a plane is accepted and allowed to carry passengers. How many hours is that? 100? 500? Is there a probationary period after?

Airliners are safe in large part because they have redundant systems, and allowing a plane to fly with a redundant system disabled/malfunctioning is a conscious choice to accept a higher safety risk. No doubt this has been calculated in a risk assessment to be an acceptable risk.

But yeah, maybe the standard isn't stringent enough for an early-manifesting failure. We're in the "infant mortality" section of the Bathtub Curve just like the MCAS failure was. Yes, maybe an unexplained failure of a critical passenger safety system in a low hours plane should trigger grounding of that plane until the cause of the failure is figured out and the failure is rectified.

[edit]
I've lost a lot of confidence in Boeing since the MCAS debacle, but I'm cognizant of the...risk.... in this being overblown. Airliners are safe, but nothing is completely safe. I don't want airliners to become the new nuclear power where they are so safe that a single accident is held up as evidence they are unacceptably, irredeemably unsafe.

 

[Borg]

My "stuck" throttle this spring: https://www.physicsforums.com/threads/my-in-flight-incident.1058960/

That link gives a permission error for non-Mentors.

 

[dlgoff]

That link gives a permission error for non-Mentors.

Yea. I'd really like to be able to view that post.

 

[russ_watters]

Ok, @Borg and @dlgoff I've created a new thread for it here (and updated the other links):
https://www.physicsforums.com/threads/my-in-flight-incident.1058960/

Guess I was....throttling who I told.

 

[dlgoff]

Ok, @Borg and @dlgoff I've created a new thread for it here (and updated the other links):
https://www.physicsforums.com/threads/my-in-flight-incident.1058960/

Guess I was....throttling who I told.

Dang! Thanks for posting that.

 

[berkeman]

Ok, @Borg and @dlgoff I've created a new thread for it here (and updated the other links):
https://www.physicsforums.com/threads/my-in-flight-incident.1058960/

Guess I was....throttling who I told.

I'm real glad that you survived that in-flight emergency. Way to stay cool-headed as the pilot of a plane that has a serious problem.

 

[256bits]

There's a set of flight tests performed that lasts a certain number of hours, in a "shakedown" period before a plane is accepted and allowed to carry passengers. How many hours is that? 100? 500? Is there a probationary period after?

Who does that?
The airplane operator, or some other agency?

If one leases or buys a plane from a manufacturer, should not the manufacturer already have the plane designated as being air worthy and transfer the certificate to the buyer upon possession of the airplane.

 

[russ_watters]

Who does that?
The airplane operator, or some other agency?

If one leases or buys a plane from a manufacturer, should not the manufacturer already have the plane designated as being air worthy and transfer the certificate to the buyer upon possession of the airplane.

I'm not sure of the specifics, but at least the manufacturer will do a set of acceptance tests, and the airline will do their own. I don't think it's directly supervised by the FAA, just reported to the FAA. There was a crash once in Europe where the pilot's crashed the plane during such a check for an airline(no passengers). I'll see if I can find it.