Was there a huge change in Boeing quality after McDonnell Douglas took over? well, there was a HUGE change in culture. I was there until 1999, two years after the “buyout” of Boeing. The St Louis mgmt “tong” basically took over and proceeded to destroy the engineering culture. The 787 program was a complete business fiasco, to the tune of $100B+ in losses, due to the “outsourcing” model and other shortcuts. The delays and cost overruns on that program meant there were no resources to develop a new single aisle aircraft. And the mgmt focus was on the stock price, which they have tried to prob up with 10’s of billions of stock buybacks. When AA was about to place a huge order for A320neos instead of 737NGs, Boeing mgmt paniced and launched the 737Max on a rush schedule with limited resources. Hence the string of bad design decisions. The Max grounding and then Covid had a huge aircraft production impact, leading to mass layoffs; the subsequent production ramp up has been (as they usually are) difficult, which may have led to quality issues. Not helping is Boeing putting severe cost pressures on their suppliers.
Thx to Murph 9000's 11 Jan 24 22:31 post I finally understand the whole stop pad / pin thing, I'd now like to get a better understanding of how the pressure seal / gasket arrangement (internal / external) works, especially as related to the up /down, inboard / outboard movement of the door / plug. Must be some not so trivial "wiping" of the gasket. or so I suppose....
The problem with sloppy work is that the supply FAR EXCEEDS the demand
I'm starting wonder if the proximate cause was 4 missing bolts (2 in the tracks and 2 through the spring guides). This allowed to door to move upward and depart. The caveat is someone, based on a misunderstanding, overtightened the stop pins to arrest the movement of the door and keep it fixed. After time whatever was in compression around the frame creeped or shifted and the friction between the pin faces and the stop pads diminished to the point the springs could act on the door.
Just an uneducated theory because a cross section drawing of the door is unavailable.
The person may have used paint containers such as this:
These are clamps, not stop pads. Is it plausible someone mistook to door stop pins for clamps when in reality the plug is not meant to be clamped at all?
All of you complaining about the “complexity” of the plug door design should see the complexity of the actual operable passenger doors. The plug door is relatively simple. And the basic configuration has to be convertible into an operable exit door.
The Max plug door design is likely the same as that used for the 737-900 (NG), which has been flying for many years. And similar plug doors have probably been used on other aircraft models.
As said before it seems highly likely the the 4 retainer bolts were not installed. One can speculate as to why, and it helps to understand how aircraft assembly factories operate. Highly choreographed, and if things get out of sequence, or rushed, or cycle time reduction pressures too high, or people are nit trained, escapes can happen. There is supposed to be robust quality oversight, but that gets viewed by mgmt as a “non value added” cost, so ………..
Not knocking the NTSB as a whole, but given the circumstances and a lifetime of trouble shooting I do feel that this one sentence was ill advised, maybe only two words;
"But Homendy said she believes these three incidents are likely unrelated to the door plug blowout and that Alaska’s decision makes sense."
The engineers at the NTSB may be rolling their eyes at that statement.
Three alarms and then a blowout?
That's a huge red flag to a trouble shooter.
(Or has Boing's quality deteriorated to the point that frequent pressurization alarms are common?)
Three spurious back door alarms will ground a school bus.
-------------------- Ohm's law
Not just a good idea; It's the LAW!
I have to agree with waross on this one. Though the NTSB has done some outstanding work, they are not infallible and are showing some troubling attitudes.
"A class-action lawsuit was filed Thursday against aircraft manufacturer Boeing on behalf of multiple passengers who were aboard an Alaska Airlines flight last week that was forced to make an emergency landing in Portland, Oregon, after a portion of the fuselage blew out in midair.
The lawsuit — filed on behalf of six passengers and a relative in King County Superior Court in Washington state, where Boeing is headquartered — alleges that "the event physically injured some passengers and emotionally traumatized most if not all aboard."
On the night of Jan. 5, Alaska Airlines Flight 1282 was carrying 174 passengers and six crew members bound for Ontario, California, when a door plug of blew out just minutes after the Boeing 737 Max 9 had taken off from Portland."
For those that have not seen this, the Boeing corporate takeover and subsequent demise of engineering QA/QC can be seen in the aptly named documentary "Downfall" (Netflix).
If the springs were missing or weak, that would have helped to prevent the incident. The springs assist in opening the plug (and closing it), not keeping it closed. If the springs were too strong, it's highly unlikely that they would have been able to overcome 4 correctly fitted locking bolts.
Do the people bitching about Alaska ignoring or not properly responding to the warnings not realize that Boeing documentation for the aircraft lists the inspections, repairs and actions that need to happen when the warning goes off? The airline aren't sold a plane and left to blindly figure out how to address any issues with the plane.
If there aren't enough inspection and repair steps after the warning before the plane can fly again then that is also squarely Boeings fault alone.
The problem could be seen this way - Alaska had several of the same problem and the Boeing solution provided didn't work. Knowing that the solution didn't work, Alaska kept using the plane.
This was the same problem that Lion Air faced before they crashed - a serious number of AoA sensor failures they could not figure out on a relatively new plane. They finally replaced the sensor and immediately got another AoA sensor failure. And then put the plane back into service to crash the next day.
Alaska did not offer that they had found the root cause of the spurious warnings and it was corrected. They recognized the severity of the problem by removing the plane from ETOPS use.
The ongoing cabin pressure warnings didn't require taking it out of ETOPS. As Juan Browne / blancolirio explained, ETOPS operation allows for loss of pressurisation and the increased fuel burn that would result from returning from mid-ocean at 10,000 feet.
Alaska most likely were operating in "abundance of caution" mode, combined with wanting to keep the plane near maintenance facilities until they figured out what was going on with it. Cabin pressurisation issues are serious, but have very well trained and planned contingencies that do not require grounding an aircraft and performing extraordinary investigation.
