Not F2B but .... B737max door ..

[frank williams]

Looking at the pictures of the fuselage interior of the B737 door plug that blew out, looks like the attach points just didn't have fasteners installed.  The attach points seem to be clean.  Any NWguys have inside knowledge?

Reminds me of how I test fitted the insert for an arrowshaft pushrod  and forgot to go back and epoxy it in.  It worked fine for several years, but, you guessed it, two weeks before the Nats, it let go in a hard pullout.

[Jim Svitko]

Is this the same family of aircraft that was grounded some time ago for another problem?

[spare_parts]

How many flights did it make before the door fell off?

[Arlan McKee]

How many flights did it make before the door fell off?

I think it was around 145 flights. That's almost brand new for a commercial airliner.

[Peter in Fairfax, VA]

The ATC audio is a dramatic piece of audio.  My impression First Officer on comms.   Kinda wonder why audio system fidelity hasn't improved since 1945.

[Steve Helmick]

And they wonder why I only slack off my seatbelt a little bit. I prefer to fly with an airplane.  Steve

[Dave Hull]

From a seemingly knowledgeable post from the Blanco Lirio website:

"I did 43 years at Boeing in Commercial Airplanes with 31 years in QA. As Juan says this is a plug type door. These types of doors have been used on all Boeing transports back to the 707 and are very reliable. They should not be confused with the cargo doors such as the 747 door involved in the United Airlines flight 811 accident. Those pegs sticking out of the door frame are door stops. There is a matching set of stops on the door. The set of stops on the door are inside of the door frame. The pressurization of the airplane pushes the door against the stops in the door frame. The way the door opens there is a gate at the bottom of the door that folds in allowing the door to move down so the door stops will clear each other and move outward. Part of the mechanism includes pins protruding from the door frame and cam locks on the door side. This cam/pin arraignment is the locking system. Inside the door there is an arrangement of gear boxes, linkages and torque tubes that move the end gate, cam locks and the door moving down. When the door is properly rigged the door stops are adjusted to ensure proper contact and the push rods are adjusted to ensure the linkage goes over center to prevent unwanted movement and subsequent opening of the door. Proper rigging is also dependent upon having the weight of the door slide compensated for. A deactivated door does not have the escape slide. If the door was rigged with the slide weight and then deactivated, then the rigging could possibly be incorrect. Either the door was mis rigged or a safety device was left off the door assembly allowing the rigging to change. These doors are installed and rigged by Spirit Aviation (formerly Boeing of Wichita)."

--Jim Palmer

I think they were very lucky that no one was sitting next to the blown-out door. One source stated that one person's T-shirt was sucked off of him as the plane depressurized.

[frank williams]

Thanks Dave
Finding the door will tell the tale. 

[Colin McRae]

On the news this morning they said they found the door. And if the blow-out happened at say 30,000 ft the plane probably would have been lost.

[Brett Buck]

Thanks Dave
Finding the door will tell the tale.

     I also note that the NTSB representative said they found "no damage" to the airplane side of the interface. That very strongly suggests that the latches worked themselves loose somehow. That would also explain the warning messages they had been getting, there is almost certainly a limit switch somewhere on the door latch mechanism that tells you if the mechanism has moved (like is someone start to pull the handle).

   Interesting, putting a blank trim panel over it makes it much more difficult to inspect, or to easily notice that the handle has moved.
 
    Brett

[Gary Mondry]

This seems to be a pretty informed explanation of the “plug door option” on the 737:

https://youtu.be/maLBGFYl9_o?si=PqSHxM7AcjQcY4RT

[frank williams]

looks like locking bolts were missing

[Brett Buck]

looks like locking bolts were missing

   Sure does. Without that I assume it works like an regular door, and that the warnings were generated when it somehow came unlatched, and then finally worked it's way all the way off.  I read somewhere that some subcontractor installs (or doesn't) the plugs and the bolts when they are building the interior.

      Brett

[AMV]

No one was injured. Even two iPhones survived the 16k fall.

-Andrey
 

[Dan McEntee]

No one was injured. Even two iPhones survived the 16k fall.

-Andrey
 

   What is the terminal velocity of a cell phone?? Just in case I get on Jeopardy and the question comes up!
    Type at you later,
    Dan McEntee
 

[AMV]

   What is the terminal velocity of a cell phone?? Just in case I get on Jeopardy and the question comes up!
    Type at you later,
    Dan McEntee
 

Dan,
According to a post-doc researcher at the Institute of Theoretical Astrophysics at the University of Oslo, it's about 30 mph.

-Andrey
 

[Dan McEntee]

Dan,
According to a post-doc researcher at the Institute of Theoretical Astrophysics at the University of Oslo, it's about 30 mph.

-Andrey
 

   If it landed on grass or turf of some kind I can believe it would still function. I' just glad that some guy didn't try to chase it and grab it as it was going out the door!
    Type at you later,
   Dan McEntee

[Dwayne Donnelly]

From what I've watched and read the plug was removed to install the interior and then reinstalled, reports are nothing on the plane is damaged, that means the plug blew away cleanly which to me sounds like someone really screwed up reinstalling the plug and not a design flaw, at least lets hope that's what it was and this isn't going to happen again.

[Marty Hammersmith]

I'm glad that 63 lb door landed in a yard and not on someone. Amazing that they found those phones. It makes it seem possible that they might find a bolt or how about that's kid's shirt? I'm surprised that the door plug opens outward. You'd think they'd have to come IN so that they are locked in place by the pressurization instead of always in tension trying not to get blown out by the pressure.

[Paul Walker]

I'm glad that 63 lb door landed in a yard and not on someone. Amazing that they found those phones. It makes it seem possible that they might find a bolt or how about that's kid's shirt? I'm surprised that the door plug opens outward. You'd think they'd have to come IN so that they are locked in place by the pressurization instead of always in tension trying not to get blown out by the pressure.

It is held in by pressure. The door stops on the fuselage are clearly visible. The 4 fasteners in question keep the door sitting on those stops. If those 4 bolts went missing, it will allow the door to move and not set on the stops properly.
The door stops are the same as have been.used for many decades. It appears that the retention/location fasteners are the culprit.

[Dwayne Donnelly]

This guy is awesome.

[Dan McEntee]

   If there were 171 people on board, I find it strange that no one was sitting in that row!! I don't know what the capacity is of the airplane but if I can change seats to a row with more room I'm gonna ask a flight attendant if I can move. From what little video I have seen from inside the cabin after it happened the airplane looked pretty full.
   Type at you later,
  Dan McEntee

[spare_parts]

Phones have GPS, not hard to find if functional.

[Chris McMillin]

Phones have GPS, not hard to find if functional.

I figured that's how they found the door. Chase the phones, the door isn't far away.
Chris...

[Air Ministry .]

These doors are nothing new .

your better off without them , thats why Motorcycles are much safer .   

[Rusty]

My opinion from listening to the information is that the manufacturer did not assemble it properly.   I do not see any way that bolts with castle nuts and cotter pins can come unfastened.   The bolts will break before enough pressure can be applied to turn the nut and sheer the cotter pin allowing the nut to turn off.   

[Brett Buck]

It is held in by pressure. The door stops on the fuselage are clearly visible. The 4 fasteners in question keep the door sitting on those stops. If those 4 bolts went missing, it will allow the door to move and not set on the stops properly.
The door stops are the same as have been.used for many decades. It appears that the retention/location fasteners are the culprit.

   Just for my own idle curiosity, when it is used as a door, something else must hold it, right? Like a movable stop that goes through the same hole as the bolt? Is there some limit switch somewhere that tells when it is off the stops?

    With a blank finisher over the inside, I would suppose it was possible that the door started to work loose without anyone noticing, but it would have been clear that it was not flush if you looked at it from the outside.

     Brett

[Roy DeCamara]

Every one keeps calling this thing a door.  It is an emergency exit opening, not in use for this particular airplane because of lower density cabin configuration. The piece blown out is a plug.  Much smaller, lighter and much less complicated than a cabin entry/exit door.

[Marty Hammersmith]

Right. This is a door plug. It is not a door though maintenance can swing it down if necessary for some service need.

[spare_parts]

Juan Brown said there are no sensors on the plug when it's not an emergency door.

This guy went looking for debris and found one of the phones... who would have thought.

https://www.oregonlive.com/portland/2024/01/man-who-found-alaska-airlines-phone-says-he-searched-while-killing-time-before-lunch.html

NTSB determination will be interesting when it's released.

[Steve Dwyer]

Let's call it the Monday morning door "plug".

[AMV]

The iPhone that survived the fall will be a good "plug" for Apple