Alaska Airlines grounding fleet of Boeing 737 Max jets for inspection after emergency landing

[PigsDad]

Before a door plug flew off a Boeing plane, an advisory light came on 3 times​

https://www.npr.org/2024/01/08/1223427243/boeing-flight-door-plug-alaska-airlines

Kurt

 

[billymach4]

I can see how these bolts may have gone missing prior to the interior was completed. The inspection of these bolts may have been neglected to be checked. The the interior was finished never to be checked again.

 

[billymach4]

Yup. If these bolts were never installed prior to the interior upholstery being installed then that would explain how the door blew off.
There is no way to confirm the installation of these bolts with the interior covering up the view of this hardware.

It is entirely plausible that the factory neglected to ensure these bolts were installed.

 

[davidvel]

Looks as if there might be something more systemic involved here. United found loose bolts on the plug when it did it's inspections.

Alaska, United find loose hardware during inspection of 737 MAX 9s

Alaska Airlines and United Airlines said Monday they found loose hardware during inspections of their 737 MAX 9 aircraft.

www.seattletimes.com

This points to the Spirit Aerosystems facility in Wichita, where the fuselages are assembled.

At one time Boeing did all fabrication and assembly so they had control of the whole process. Again, the bean counter suits from McDonnell Douglas decided to outsource much of the production to free up capital and reduce costs, and there has been a raft of production issues associated with that move.

While they build them, Spirit does not complete the final assembly and mounting of these plugs in the sealed position. This is because Boeing utilizes these access points during final assembly of the aircraft. The final installation (and confirmation) of the plugs' mounted upper and lower locking bolts would be done by Boeing prior to delivery.

The plug was found intact, with only minor impact damage, and from photos and videos little apparent structural damage. Many experts are pointing to multiple locking bolts not being properly in place prior to the ejection.

The process of building these aircraft involves redundant checks, checklists, and sign-offs of such critical parts/installations, down to the bolt. It is astonishing how this accident was able to occur, but obviously it did. But I don't think it will take the NTSB long to figure out how it happened.

 

[T_R_Oglodyte]

I can see how these bolts may have gone missing prior to the interior was completed. The inspection of these bolts may have been neglected to be checked. The the interior was finished never to be checked again.

Are you sure? I was under the impression that there was a maintenance schedule for the aircraft that did involve removing the interior finish to allow for routine inspection of the inside of the fuselage.

While they build them, Spirit does not complete the final assembly and mounting of these plugs in the sealed position. This is because Boeing utilizes these access points during final assembly of the aircraft. The final installation (and confirmation) of the plugs' mounted upper and lower locking bolts would be done by Boeing prior to delivery.

Thanks for the clarification.

 

[billymach4]

While they build them, Spirit does not complete the final assembly and mounting of these plugs in the sealed position. This is because Boeing utilizes these access points during final assembly of the aircraft. The final installation (and confirmation) of the plugs' mounted upper and lower locking bolts would be done by Boeing prior to delivery.

The plug was found intact, with only minor impact damage, and from photos and videos little apparent structural damage. Many experts are pointing to multiple locking bolts not being properly in place prior to the ejection.

The process of building these aircraft involves redundant checks, checklists, and sign-offs of such critical parts/installations, down to the bolt. It is astonishing how this accident was able to occur, but obviously it did. But I don't think it will take the NTSB long to figure out how it happened.

Having worked for Grumman many moons ago on a final assembly line.....

I can see how those bolts would be overlooked and sealed up by the interior upholstery. Even with the best of quality control... Its a human induced breakdown of checks and cross checks.

 

[billymach4]

Are you sure? I was under the impression that there was a maintenance schedule for the aircraft that did involve removing the interior finish to allow for routine inspection of the inside of the fuselage.

Thanks for the clarification.

The aircraft was barely 2 months out of the factory. That level of inspection has not yet been necessary. I am sure. YES.

 

[T_R_Oglodyte]

And now Alaska has found more loose bolts in its inspections.

 

[T_R_Oglodyte]

The aircraft was barely 2 months out of the factory. That level of inspection has not yet been necessary. I am sure. YES.

Certainly for that particular aircraft, it wouldn't yet have been inspected. I'm querying your statement that with a finished interior, it would never be inspected again.

 

[billymach4]

Certainly for that particular aircraft, it wouldn't yet have been inspected. I'm querying your statement that with a finished interior, it would never be inspected again.

In that respect yes it would eventually get inspection. But not within the 2 months since delivery from the factory.

Aircraft maintenance checks - Wikipedia

en.wikipedia.org

 

[Ken555]

Apparently he’s a physics teacher.

Portland teacher recounts finding Boeing door plug in his yard

The piece of the plane’s fuselage landed in Bob Sauer’s yard, not far from his house. “So I’m really glad it landed where it did.”

www.opb.org

Sent from my iPad using Tapatalk

 

[JIMinNC]

The 737 Max 9 has a predecessor aircraft that is structurally similar called the 737-900ER. The 737-900ER has been around since 2006 and over 500 are flying worldwide. Interestingly, I just learned that apparently the -900ER offers a similar (or maybe even the same) extra door for high seating capacity configurations as does the Max 9. The -900ER also offers a plug if capacity is configured for 189 or less:

"The 737-900ER (Extended Range), which was called the 737-900X before launch, was the final and largest variant of the Boeing 737 NG line....an additional pair of exit doors and a flat rear pressure bulkhead increased maximum seating capacity to 220 passengers. Airlines may deactivate (plug) the additional exit doors if the total configured capacity of the plane is 189 passengers or less."

With over 500 737-900ERs flying for 18 years, it will be interesting to see if the plug configuration in question now is unique to the -9 Max or is shared with the older -900ER. If it's the same as the older airframe, it begs the question why the problem is just now manifesting itself? Did some process change in final assembly that made what may prove to be an assembly error more likely? I also wonder if they may inspect some of the older 737-900ER door plugs to see if the problem is there as well?

 

[PigsDad]

United Airlines Confirms It Has Found Loose Bolts On Five Boeing 737 MAX 9 Door Plugs​

United Airlines Confirms It Has Found Loose Bolts On Five Boeing 737 MAX 9 Door Plugs

United Airlines has confirmed that it has found loose bolts and other issues affecting emergency exit door plugs on at least five Boeing 737 MAX 9 aircraft in its fleet after it began FAA-mandated inspections following a blowout on Alaska Airlines flight 1282 on Friday evening. The Chicago-based...

www.paddleyourownkanoo.com

Kurt

 

[TheHolleys87]

I'm sure that this story will soon appear in Iphone ads. I don't understand why my daughter's phone doesn't work when her dog knocks it off the sofa.

What kind of case does she have? When I get a new phone, I don’t take it out of its box until I have the case ready to put on it. All our floors are tile, and I know that inevitably I’ll drop the phone on them.

 

[davidvel]

The 737 Max 9 has a predecessor aircraft that is structurally similar called the 737-900ER. The 737-900ER has been around since 2006 and over 500 are flying worldwide. Interestingly, I just learned that apparently the -900ER offers a similar (or maybe even the same) extra door for high seating capacity configurations as does the Max 9. The -900ER also offers a plug if capacity is configured for 189 or less:

"The 737-900ER (Extended Range), which was called the 737-900X before launch, was the final and largest variant of the Boeing 737 NG line....an additional pair of exit doors and a flat rear pressure bulkhead increased maximum seating capacity to 220 passengers. Airlines may deactivate (plug) the additional exit doors if the total configured capacity of the plane is 189 passengers or less."

With over 500 737-900ERs flying for 18 years, it will be interesting to see if the plug configuration in question now is unique to the -9 Max or is shared with the older -900ER. If it's the same as the older airframe, it begs the question why the problem is just now manifesting itself? Did some process change in final assembly that made what may prove to be an assembly error more likely? I also wonder if they may inspect some of the older 737-900ER door plugs to see if the problem is there as well?

My understanding is it is essentially the same plug system. My guess is all the other planes has the vertical lock bolts in place, and this accident was caused by a one-off (horrific) mistake where the bolts were not at all (or properly) installed. Notably, the right side plug was inspected by NTSB, with no anomalies found.

Note there is no confirmation that the loose bolts found on other planes are the vertical lock bolts in question here. There is photo floating around purportedly of a UA plane showing loose bolts, which are different. In theory those bolts could all be gone on one fitting but the door still could not come loose as other points would keep it from moving up (and then out.) That is why you don't see any lock nuts and cotter pins on those bolts.

 

[Tia]

I saw this today https://finance.yahoo.com/news/boeing-supplier-warned-parts-defects-190904050.html

 

[Talent312]

... All our floors are tile, and I know that inevitably I’ll drop the phone on them.

I tripped over a curb and my phone flew onto the pavement
(as did I). Notwithstanding a few hairline cracks, it works fine.

 

[easyrider]

No. That's what trip insurance is for.

So far, this couple has received credits and cash of just over $700 each from Alaska Airlines as compensation for the hotel stays, parking fee's and meals. When they get back from this trip they will also get compensated for the two nights in Hawaii they paid for but missed, parking fee in Everret and other things which I'm not sure about. I'm thinking it will be about $2000 total in the form of airline credits and cash.

My bet is Boeing's insurance will eventually be paying for this.

Bill

 

[easyrider]

What kind of case does she have? When I get a new phone, I don’t take it out of its box until I have the case ready to put on it. All our floors are tile, and I know that inevitably I’ll drop the phone on them.

We do the same with cases. This last case has a lever on the back that folds out. I guess it's a kick stand. I don't like it. Too bulky.

Bill

 

[bnoble]

My bet is Boeing's insurance will eventually be paying for this.

Or Alaska/Boeing is eating it as good-will. It's not good word-of-mouth when your planes fall apart in the air.

 

[easyrider]

Or Alaska/Boeing is eating it as good-will. It's not good word-of-mouth when your planes fall apart in the air.

I really don't remember hearing about a big commercial airplane having a door sized hole section just falling off ever. I'm told a DC 10 had it's roof come off years ago. I don't remember that incident.

It's way different in real life than in the movies. In the movies everything would have been sucked out of the hole.

Bill

 

[Ken555]

I really don't remember hearing about a big commercial airplane having a door sized hole section just falling off ever. I'm told a DC 10 had it's roof come off years ago. I don't remember that incident.

Aloha Airlines Flight 243 - Wikipedia

en.wikipedia.org

 

[JIMinNC]

I really don't remember hearing about a big commercial airplane having a door sized hole section just falling off ever. I'm told a DC 10 had it's roof come off years ago. I don't remember that incident.

Aloha Airlines Flight 243 - Wikipedia

en.wikipedia.org

@Ken555 has noted the most famous explosive decompression incident, Aloha 243, but it wasn't a DC-10, it was a 737-200.

I do recall a famous DC-10 crash in Sioux City, Iowa in 1989 - United 232. The plane's center tail-mounted engine failed, and a section of a fan disk sliced through the fuselage and severed the hydraulic lines, meaning the pilots lost control of ailerons, elevator, and other control surfaces. The flight crew managed to maneuver and turn the airplane using differential power on the two remaining wing-mounted engines. They were able to line up with a runway in Sioux City and descend for landing but lost partial control at touchdown. The plane came to rest in a corn field beside the runway. There were 112 fatalities, but 189 survived thanks to the crew managing a semi-controlled crash landing rather than an out of control crash.

The other notable structural failure that I can immediately recall was American Airlines 587 in November 2001. It was an Airbus A300 that lost its entire vertical tail section on departure from JFK airport in New York. The tail section fell into Jamaica Bay and the plane crashed into a neighborhood in Queens killing all 260 people on board and five people on the ground. That accident was ultimately not blamed on structural flaws, but on a pilot's overly aggressive use of the rudder pedals to counteract wake turbulence from a 747 departing ahead of it. Those aggressive control inputs over-stressed the vertical stabilizer, causing it to fail. Interestingly, that crash was the last fatal crash in the US involving a US airline mainline jet - now over 22 years without a fatality. There have been a couple regional aircraft crashes since then, but that was the last fatal mainline jet.

 

[JIMinNC]

It's way different in real life than in the movies. In the movies everything would have been sucked out of the hole.

Bill

A lot more would have been sucked out of that hole had the decompression happened at a cruising altitude of 30,000+ or close to it. While movies often over dramatize, the depictions of explosive decompression at altitude aren't that far from reality.

The Alaska Airlines decompression happened at only 16,000 feet just a few minutes after departure. While the cabin was already pressurized at that altitude, the pressure differential was not nearly as great as it would have been had the plane been at cruise altitude. It's the sudden pressure differential, with the pressurized air from inside rushing into the thin air aloft that creates the sucking force in a sudden decompression.

In fact, in an unpressurized airplane like the ones I fly, pilots don't even need to have supplemental oxygen unless we are going to fly at over 12,500 feet for more than 30 minutes or above 14,000 feet for any time. Passengers only need supplemental oxygen above 15,000 feet. So the Alaska 737 was only 1,000 feet above the altitude where passengers would be required to have oxygen. Had the plug come out a few minutes later, the story would likely be a bit different.

 

[JIMinNC]

I'll add to the above that it's perfectly safe to fly in an airplane without a door as long as you are not at high altitude and you are safely strapped in. I've done it many times to get photos of other aircraft like this one.