Boeing 737 MAX family NEWS ONLY

iverson said:
The FAA is compromised as well. It is chartered to both insure both the viability/profitability and the safety of commercial aviation. Historically, the former has always outweighed the latter. Until we have an independent safety agency--an NTSB with regulatory and enforcement power--737MAX-type problems are inevitable.
Click to expand...
The way to make sure no-one dies on an airplane is to make sure no airplanes fly.

That's literally why the FAA has both jobs. To make sure the corrective actions for safety don't compromise the ability to actually fly.

Example: remember TWA 800? the 747 that somehow blew up shortly after takeoff from New York? One of the NTSB recommended actions was to add a nitrogen fuel tank inerting system to all aircraft, not just all 747-100s. This would entail a liquid nitrogen tank, heat exchanger, and associated piping to every tank, plus a barometric equalizer valve to make sure that fuel tank pressure never exceeded ambient atmospheric. Not to mention the associated electrical wiring and any electronic controls. Ignoring the engineering costs and costs of installation (several million dollars per plane), that adds up to about 2000lbs of weight for the heavies, and somewhere around 200lbs for a Cessna 150-206 sized aircraft.

Side note: the only two three US military planes I know of with fuel tank inerting systems are the Blackbird, the A-10, and the AH-64. Blackbirds due to temperatures in the fuel tanks, A-10s and Apaches due to their job involving people trying to blow large holes in them.

At about the size of most General Aviation or light business twins (King Airs) and smaller planes, the inerting system becomes more extra weight than the aircraft can legally take off with. Oops, you just prevented all future flight training, attempting to prevent a condition that to my knowledge has never led to the loss of a light aircraft. Nevermind that the Cessnas are all flying with much more volatile avgas instead of jet fuel.

And now you must have someone on the airfield who is capable of handling liquid nitrogen 24/7. Few A&Ps will mess with that, no basic ramp worker should touch that because their employer's insurance won't cover them doing it at all, so you better get a Norco or Airgas LN2 plant and truck at every airport across the entire world. And then that LN2 refiller will probably have to be trained as an A&P just to sign the maintenance books.

Total cost to the US alone? High billions of dollars the first year. And the closing of thousands of small airports because they can't get an LN2 worker. Complete halt to all flight training with any airplane smaller than a Cessna 208 Caravan. Complete halt to all general aviation planes smaller than a Cessna 208. Likely halt to flight of all warbirds, because they don't physically have space to install a fuel tank inerting system.




DrRansom said:
That sounds pretty desperate.

Also, can Boeing afford to bring Spirit Aerosystems up to quality?
Click to expand...
They can't afford NOT to.
 
Last edited:
That Boeing employee saying that the plug doors are removed a lot during final assembly after delivery from Spirit certainly puts the onus back on Boeing as well as the companies confusion over whether the door plugs arrive installed in a first fix or final fix condition. (would certainly explain the numerous reports of loose bolts in Airline inspection and Boeing tightening the bolts on the plug door on the opposite side to the one that fell off of the very plane in question)
 
WatcherZero said:
Boeing have announced they will be doing more QA checks on both their own and Spirits work with a Boeing team to be based at Wichita, they are bringing in a 3rd party to provide independent assessment of their Quality testing practises and airline customers will now be allowed to do spot inspections of its factories.
Click to expand...
Unfortunately, unless Boeing takes the fuselage work back in-house, I do not see any of these measures having more than a short-term effect at best.

The whole point of corporate outsourcing is to cut costs while shifting responsibility for the cost-cutting methods adopted. To generate the outsized investor returns that Boeing management wanted, the company had to sharply reduce labor costs. That meant doing things that couldn't be done at Boeing proper--breaking union contracts and work rules, hiring less skilled workers, adopting workarounds that would look bad if adopted on Boeing's assembly lines, and accepting liability for the consequences up front. Outsourcing let Boeing management get what it wanted while convincing itself that it was avoiding the negatives. Boeing set the pricepoint it wanted for the work, and left Spirit to figure out how to meet the target and still make a profit of its own.

The incentive for--and necessity of--cutting corners in such a situation is obvious. By the time Spirit got the work, the selling price had already been set by the need to undercut Airbus. The cost of the airplane, as determined by labor and materials, was pretty much baked in by the design. The difference--the potential profit--had already been skimmed off by Boeing management.
 
This is how to save Boeing;
You have Mitt Romney in a pillory in this frigid weather just outside the NYSE and force Boeing executives to file past as Eli Roth stands there with a baseball bat daring the vipers to sell off in panic mode.
 
Scott Kenny said:
The way to make sure no-one dies on an airplane is to make sure no airplanes fly.

That's literally why the FAA has both jobs. To make sure the corrective actions for safety don't compromise the ability to actually fly.

Example: remember TWA 800? the 747 that somehow blew up shortly after takeoff from New York? One of the NTSB recommended actions was to add a nitrogen fuel tank inerting system to all aircraft, not just all 747-100s. This would entail a liquid nitrogen tank....

And now you must have someone on the airfield who is capable of handling liquid nitrogen 24/7.
Click to expand...

Alternately, use an OBIGGS (opposite of an OBOGS), they're out there and in use.

"After the TWA Flight 800 crash, a 2001 report by an FAA committee stated that U.S. airlines would have to spend US$35 billion to retrofit their existing aircraft fleets with inerting systems that might prevent such explosions. However, another FAA group developed a nitrogen-enriched air (NEA) based inerting system prototype that operated on compressed air supplied by the aircraft's propulsive engines. Also, the FAA determined that the fuel tank could be rendered inert by reducing the ullage oxygen concentration to 12% rather than the previously accepted threshold of 9 to 10%. Boeing commenced testing a derivative system of their own, performing successful test flights in 2003 with several Boeing 747 aircraft."

"The FAA estimated the cost of the program at US$808 million over the next 49 years, including US$313 million to retrofit the existing fleet. It compared this cost to an estimated US$1.2 billion "cost to society" from a large airliner exploding in mid-air. "

Not sure what the final status of FAA's proposed rule is.

NTSB's job is to recommend how to stop an accident happening, FAA's is to decide if NTSB's recommendation can be done cost-effectively. NTSB have a long list of recommendations FAA have decided aren't cost effective or haven't implemented for other reasons, some more reasonable than others. It's the ones that have been recommended multiple times (ie across multiple investigations) that are probably the greatest concern.

The stuff on NTSB's current most wanted list is really basic: Mandate every air carrier to have a safety management system; mandate crash survivable FDRs (there's more, but NTSB covers more than aviation, difficult to get more basic than mandate wearing a helmet on motorcycles).

See https://www.ntsb.gov/Advocacy/mwl/Documents/2021-2022/2021-2022-MWL-Recommendations-Report.pdf
 
Whopper said:
We're talking about the bare minimum here. I don't think bolting on a door correctly is that difficult of a task.
Click to expand...
1) It's not a door. It's the plug that goes into the fuselage that fills the hole where a door would be.

2) It made it past at least 3 QA checks with missing or loose bolts. Apparently it really is that fucking difficult a task.
 
Boeing has opened an R&D center in Karnataka, India to design aircraft specifically for the Indian market.... I presume that means grab handles on the outside of the aircraft.

www.wionews.com

India PM Modi says won’t be long before Boeing makes aircraft in India

India will not have to wait too long for a Boeing aircraft that is designed and manufactured in the subcontinent, Prime Minister Narendra Modi said at the inauguration of the planemaker's engineering centre in Bengaluru on Friday. The Boeing India Engineering & Technology Center (BIETC) in the...
www.wionews.com
 
WatcherZero said:
Boeing has opened an R&D center in Karnataka, India to design aircraft specifically for the Indian market....
Click to expand...
Modi said it will design aircraft for the Indian market, that's a bit different from Boeing saying it. Boeing's had facilities like this in other places, notably Moscow. They don't design entire aircraft, they do project work and research. Hell, Boeing Seattle barely designs new aircraft nowadays - the last ab initio Boeing design is the 787 and that had first flight in 2009.

If Boeing can't justify launching the New Midsize Airplane for the world market, there's no way they can justify launching one for just the Indian market.
 
DWG said:
NTSB's job is to recommend how to stop an accident happening, FAA's is to decide if NTSB's recommendation can be done cost-effectively.
Click to expand...
This division of labor is exactly the problem in my view. In FAA practice, "cost-effectively" means "as profitably as possible for the airlines".

The FAA was set up primarily to promote the aviation industry at a time when airlines and manufacturers were barely viable financially (and not all that safe). So it has always viewed its flight safety responsibilities in promotional terms: assure the public that flying is safe enough and thus protect airline and manufacturer revenues (particularly after a disaster); keep airline and manufacturer costs to an absolute minimum and thus protect airline and manufacturer profits.

This foundational conflict of interest has always been a problem with the FAA. But it has gotten much worse since airliner manufacture in the US became a monopoly. Promoting the manufacturing side of the US aviation industry now means promoting Boeing and its subcontractors. The FAA defers to Boeing management on regulatory issues. It lets Boeing management decide what are or are not cost-effective measures. It lets Boeing managers do the inspections formerly done by FAA inspectors. Recetly, it even drags its feet on grounding defective Boeing planes.

The ongoing Boeing 737 MAX fiasco has become such a complicated mess that no single step is likely to fix it. But one point seems clear to me: we have to strip the FAA of its authority over safety issues. To the extent that fostering commercial aviation is still necessary, entrust that role to the FAA. Let it manage the airways. But give the NTSB the authority to define and enforce safety requirements.
 
iverson said:
But give the NTSB the authority to define and enforce safety requirements.
Click to expand...
NO.

Again, the NTSB makes recommendations that would cost billions to implement. Per airport.

Now, if you don't make those changes, planes don't fly there anymore. Congratulations, you just shut down the entirety of aviation except to and from the biggest cities in the US.
 
Scott Kenny said:
The way to make sure no-one dies on an airplane is to make sure no airplanes fly.

That's literally why the FAA has both jobs. To make sure the corrective actions for safety don't compromise the ability to actually fly.

Example: remember TWA 800? the 747 that somehow blew up shortly after takeoff from New York? One of the NTSB recommended actions was to add a nitrogen fuel tank inerting system to all aircraft, not just all 747-100s. This would entail a liquid nitrogen tank, heat exchanger, and associated piping to every tank, plus a barometric equalizer valve to make sure that fuel tank pressure never exceeded ambient atmospheric. Not to mention the associated electrical wiring and any electronic controls. Ignoring the engineering costs and costs of installation (several million dollars per plane), that adds up to about 2000lbs of weight for the heavies, and somewhere around 200lbs for a Cessna 150-206 sized aircraft.

Side note: the only two US military planes I know of with fuel tank inerting systems are the Blackbird and the A-10. Blackbirds due to temperatures in the fuel tanks, A-10s due to their job involving people trying to blow large holes in them.

At about the size of most General Aviation or light business twins (King Airs) and smaller planes, the inerting system becomes more extra weight than the aircraft can legally take off with. Oops, you just prevented all future flight training, attempting to prevent a condition that to my knowledge has never led to the loss of a light aircraft. Nevermind that the Cessnas are all flying with much more volatile avgas instead of jet fuel.

And now you must have someone on the airfield who is capable of handling liquid nitrogen 24/7. Few A&Ps will mess with that, no basic ramp worker should touch that because their employer's insurance won't cover them doing it at all, so you better get a Norco or Airgas LN2 plant and truck at every airport across the entire world. And then that LN2 refiller will probably have to be trained as an A&P just to sign the maintenance books.

Total cost to the US alone? High billions of dollars the first year. And the closing of thousands of small airports because they can't get an LN2 worker. Complete halt to all flight training with any airplane smaller than a Cessna 208 Caravan. Complete halt to all general aviation planes smaller than a Cessna 208. Likely halt to flight of all warbirds, because they don't physically have space to install a fuel tank inerting system.





They can't afford NOT to.
Click to expand...
Another alternative is to cool engine exhaust and pipe it into fuel tanks to “inert” ullage. Carbon dioxide or carbon monoxide will prevent ullage from catching fire during the first impact of a crash. Russians invented that system many decades ago.
 
Last edited:
I presume you would have major issues with particle contamination of fuel supply over time, even with filters. You would also have a (minor) weight penalty with Carbon Dioxide being 2.75 times heavier than Nitrogen (or 1.57x more cubic weight). Never mind the hefty environmental impact of all that localised release of stored contaminant gases in one location when the aircraft purge their tanks to refill them with fuel again.
 
FAA has extended the inspection to the 737-900ER which uses the same door plug design, previously the FAA said inspections weren't necessary as the last delivery was four years ago and problems would have shown themselves by now.

www.bbc.co.uk

Boeing 737-900ER: Second model to be inspected after 737 Max 9 blowout

The US regulator says the 737-900ER fleet uses the same door design as the grounded 737 Max 9s.
www.bbc.co.uk
 
Scott Kenny said:
The way to make sure no-one dies on an airplane is to make sure no airplanes fly.

That's literally why the FAA has both jobs. To make sure the corrective actions for safety don't compromise the ability to actually fly.

Example: remember TWA 800? the 747 that somehow blew up shortly after takeoff from New York? One of the NTSB recommended actions was to add a nitrogen fuel tank inerting system to all aircraft, not just all 747-100s. This would entail a liquid nitrogen tank, heat exchanger, and associated piping to every tank, plus a barometric equalizer valve to make sure that fuel tank pressure never exceeded ambient atmospheric. Not to mention the associated electrical wiring and any electronic controls. Ignoring the engineering costs and costs of installation (several million dollars per plane), that adds up to about 2000lbs of weight for the heavies, and somewhere around 200lbs for a Cessna 150-206 sized aircraft.

Side note: the only two US military planes I know of with fuel tank inerting systems are the Blackbird and the A-10. Blackbirds due to temperatures in the fuel tanks, A-10s due to their job involving people trying to blow large holes in them.

At about the size of most General Aviation or light business twins (King Airs) and smaller planes, the inerting system becomes more extra weight than the aircraft can legally take off with. Oops, you just prevented all future flight training, attempting to prevent a condition that to my knowledge has never led to the loss of a light aircraft. Nevermind that the Cessnas are all flying with much more volatile avgas instead of jet fuel.

And now you must have someone on the airfield who is capable of handling liquid nitrogen 24/7. Few A&Ps will mess with that, no basic ramp worker should touch that because their employer's insurance won't cover them doing it at all, so you better get a Norco or Airgas LN2 plant and truck at every airport across the entire world. And then that LN2 refiller will probably have to be trained as an A&P just to sign the maintenance books.

Total cost to the US alone? High billions of dollars the first year. And the closing of thousands of small airports because they can't get an LN2 worker. Complete halt to all flight training with any airplane smaller than a Cessna 208 Caravan. Complete halt to all general aviation planes smaller than a Cessna 208. Likely halt to flight of all warbirds, because they don't physically have space to install a fuel tank inerting system.





They can't afford NOT to.
Click to expand...
AH-64 has it too.
 
United CEO says hes considering cancelling the airlines order for 277 MAX-10 due to them already being five years late in delivery and the MAX-9 issues being the straw that broke the camels back.

time.com

United Airlines Will Consider Alternatives to Boeing

United Airlines' CEO says he is “disappointed” in ongoing manufacturing problems at Boeing.
time.com time.com
 
Last edited:
iverson said:
The ongoing Boeing 737 MAX fiasco has become such a complicated mess that no single step is likely to fix it. But one point seems clear to me: we have to strip the FAA of its authority over safety issues. To the extent that fostering commercial aviation is still necessary, entrust that role to the FAA. Let it manage the airways. But give the NTSB the authority to define and enforce safety requirements.
Click to expand...

The NTSB isn't set up to be able to do this kind of work, you'd have to transfer the relevant branch of the FAA to be able to cover it with experience people, which would probably make the whole thing pointless.
 
I hope we learn more but, I would say that 937 392 quality escape is not shockingly enormous for an aircraft that size. It simply means that design didn't yet go through manufacturing properly. Something was not done to trim those issues.

Notice also how the critical factor resides in decision not execution, as stated before. This is a culture issue not a design one (although I would not consider this stud assembly working in shear as a proper one).
 
Last edited:
TomcatViP said:
Seattle times report with explanation and fact checking on the whistle blower account :

www.seattletimes.com

Errors by Boeing at Renton plant led to Alaska Airlines MAX 9 blowout, industry source says

The piece that blew off an Alaska Airlines jet this month was removed and re-installed improperly by Boeing mechanics in Renton, according to a person familiar with the details of the work.
www.seattletimes.com www.seattletimes.com
Click to expand...
Seattle Times blames Boeing, but I'm inclined to worry more about Spirit given the full text in the other report. There is, possibly a final cock-up by Boeing, but whether the job of opening or removing the door was assigned to Boeing or to Spirit's onsite team is unclear, so it may be premature to blame Boeing. I'm inclined to say whoever was raising the issue should have followed through to log who was doing the fix. But on the whole I'm more worried by what we learn about Spirit

"The Boeing QA writes another record in CMES (again, the correct venue) stating (with pictures) that Spirit has not actually reworked the discrepant rivets, they *just painted over the defects*."

IMO the appropriate response would have been to escort the responsible party off site, shred their security pass for Renton and recommend to Spirit their employment be terminated, but this doesn't seem to be raising any kind of immediate escalation, which suggests it isn't the first time it's happened. This would be worrying enough as a a production line error, but it isn't a production line error, it's a response to an identified quality escape. A Spirit team whose sole job is fixing identified flaws couldn't be bothered to fix a flaw, in a door plug essential to pressurization, and hid the evidence. That says absolutely terrible things about how Spirit is working. In an ideal world you'd go back over every fix that team had done to confirm it has actually been done.

There is a second Boeing flaw here, a less obvious one. When I was seconded to BAE Systems QA, the senior guy in the desk facing was only in the office 3 or 4 days a week. The rest of the time he was running the QA department of a supplier that wasn't performing at the needed level. When they couldn't get their quality processes up to scratch on their own, we stepped in and took over their entire QA department to ensure their work met the necessary standards. It's pretty obvious that Spirit have had problems, but that's not solely Spirit's problem, it's Boeing's responsibility to ensure that Spirit fix it, or to fix it themselves.
 
Last edited:
TomcatViP said:
I hope we learn more but, I would say that 937 quality escape is not shockingly enormous for an aircraft that size. It simply means that design didn't yet go through manufacturing properly. Something was not done to trim those issues.
Click to expand...

In the whole aircraft, maybe, provided they aren't safety critical, but the original text is "in the past 365 calendar days recorded 392 nonconforming findings on 737 mid fuselage door installations (so both actual doors for the high density configs, and plugs like the one that blew out)." Boeing only delivered 387 737 Max's in 2023, so that's great than 1 quality escape per aircraft, in the mid-fuselage doors/plugs alone.

WRT design going through the manufacturing process, I presume you mean production engineering, but given how much of the 737 is grandfathered through the rules at this point, is there any guarantee they're even looking at this kind of process improvement?
 
Yeah, typo
Noticed that today.

Regarding the manufacturing challenge, IMOHO it could be fitting instructions that are not updated or incorrectly written/set as said earlier. When you have that nbr yearly, that mostly point to a recursive Quality escape which are more routinely tied with documentation.
But once again, the nbr is not shockingly enormous. What is questionable is why someone didn't put the plug on this leak of resource.
 
Last edited:
TomcatViP said:
the nbr is not shockingly enormous.
Click to expand...

To put it another way, it's a minimum 50.65% quality escape rate per door/plug assembly. It's actually significantly higher than that, but I can't find a breakdown between 737 Max 8 deliveries (no mid fuselage door) and 737 Max 9 deliveries (2 mid fuselage doors per aircraft).

A door or door plug explosively departing the aircraft in cruise (we are so lucky this happened at lower altitude) could easily bring it down or cause passenger and crew fatalities. That makes it a safety critical failure capable of causing a hull loss, which means the acceptable error rate is 1*10^-9 per flight hour.

These two numbers aren't quite looking at the same thing, but the difference between them doesn't give me the warm fuzzies.
 
Well, per se, a quality escape is something that has been identified and, most often, resolved ;)

The argumentation around the billions flight hours is then irrelevant IMOHO here.
 
TomcatViP said:
Well, per se, a quality escape is something that has been identified and, most often, resolved ;)

The argumentation around the billions flight hours is then irrelevant IMOHO here.
Click to expand...

A Quality Escape is something that has left the factory in a defective state, either through accidentally releasing a known bad batch or with the defect not discovered until it reached the wholesaler/retailer/end customer. In essence its a failure of the manufacturers quality control to identify and prevent the defective product entering the market. Calling it a 'quality escape' is just an attempt to downplay its significance by applying a soft euphemism, like serving a raw meal in a restaurant and then when the customer bites into and discovers it saying 'whoopsie, my bad'.
 
I would say no. The important aspect is that it has been identified and subject to a corrective action.
Something that is not identified is a defective assembly/part with potential catastrophic consequence.
The problem here is that a quality escape has been left to become a defect despite all the man hours and cogitations around how to deal with it. Worst of all, a recursive one that should have been the subject of a deep trough review of the assembly process.
As said earlier, and noted by others, this not a problem in executing but part of the floor management culture.

Although, IMO, a bolt relaying in shear stress is not a suitable solution.
 
Last edited:
TomcatViP said:
I would say no. The important aspect is that it has been identified and subject to a corrective action.
Something that is not identified is a defective assembly/part with potential catastrophic consequence.
The problem here is that a quality escape has been left to become a defect despite all the man hours and cogitations around how to deal with it. Worst of all, a recursive one that should have been the subject of a deep trough review of the assembly process.
As said earlier, and noted by others, this not a problem in executing but part of the floor management culture.
Click to expand...
And it's sounding like the fix is in executing some of the floor management.


TomcatViP said:
Although, IMO, a bolt relaying in shear stress is not a suitable solution.
Click to expand...
Bolts EXIST to be placed in shear stress.

6 of 8 bolts attaching the wing of a small cessna are placed in shear. Multiple shear, usually. The last 2 bolts are holding together a large 2-piece bushing that is then placed in shear.
 
It depends of the main direction of stress. You have to take into account the wing deflection. But I don't want to go OT.

Notice only, studs working in shear come usually with a shank that has an hardened surface. That's what I see in a Cessna.
 
Per the illustration, the upper bolts appear [to me] to bear very little load; that is reacted through the [blue] pin and guide assembly. Pressurization loads are outboard (to the right).

The bolt appears to only restrict the upward motion of the door plug which should be minimal once the door is fully seated. (Upward load induced by the two springs in the bottom plug door hinge assembly - mounted in the aircraft.) I should note that the bolt has to be inserted from the blind side of the Guide Track (which can be a booger) so that the castellated nut and cotter pin can be seen from the inside of the fuselage.

Mechanical Engineers - ASSEMBLE! (please comment)

1706163847015.jpeg
 
Without the safety pin, there is high risk that the bolt and nut get loose with time and vibrations. The omega section of the assembly is elastic per essence (as the bolt), hence each time the pin goes in contact with the bolt, the nut and bolt untight slightly. That's why this assembly is problematic as stated earlier.
 
TomcatViP said:
Well, per se, a quality escape is something that has been identified and, most often, resolved ;)

The argumentation around the billions flight hours is then irrelevant IMOHO here.
Click to expand...
You say that like a quality escape isn't a serious issue.

My reaction to a quality escape is a whole body shudder. A quality escape found at the customer on a safety critical assembly is a whole other level of nope.

It means the supplier's quality system isn't working, and not just in the sense of occasional failures, but daily failures (392 in a year). That is not a trivial problem in aviation. A quality escape rate of over one per aircraft on a comparatively simple, yet safety critical, assembly is horrifying. This is not a situation that should be acceptable in aviation, the sirens should have gone off long before the quality escape rate got to this point.
 
DWG said:
A door or door plug explosively departing the aircraft in cruise (we are so lucky this happened at lower altitude) could easily bring it down or cause passenger and crew fatalities. That makes it a safety critical failure capable of causing a hull loss, which means the acceptable error rate is 1*10^-9 per flight hour.
Click to expand...

See the crash of Dan-Air flight 240 . . .

admiralcloudberg.medium.com

Doors Better Left Closed: The crash of Dan-Air flight 240

A bizarre accident unfolds over England when a loose baggage door becomes lodged on the tail of an HS 748.
admiralcloudberg.medium.com admiralcloudberg.medium.com

" . . . a badly designed baggage door had come open in flight, ripped off the fuselage, and wrapped itself around the horizontal stabilizer, crippling the pilots’ ability to control the pitch of their airplane."

cheers,
Robin.
 

Please donate to support the forum.

Back
Top Bottom