PakledHostage
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Posts posted by PakledHostage
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Just now, darthgently said:
I'm running way behind this story; should have shut up.
I wouldn't say that. Your ideas were interesting. Aviation is a weird industry because it's mired in processes and bureaucracy that are hard to change, but it also has a way of incrementally improving - usually after something bad happens and then the industry and regulators get together and figure out how to stop such a thing from happening again. I am certain that changes will arise out of this. I hope it isn't just a knee jerk reaction to media pressure, but a meaningful change. From my own experience participating in those types of regulatory rule making processes, it probably won't be knee jerk. ...It will be tedious and boring, but it won't be knee jerk.
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Yes, thank you @StrandedonEarth for the link. What I was trying to get at in my long winded post (which I intended as context) was "why?". Why are these errors happening on the factory floor? I once read a great book titled "They Called it Pilot Error". It asks why otherwise rational people would go fly into a mountain or pull the wings off their airplane in a spiral dive. Just dismissing those errors as "pilot error" also dismisses important understanding of what lead to the person making the error. Similarly, why are these errors happening at Boeing? Are they understaffed and overwhelmed? Are they jaded and don't care anymore? Are they getting pressure from above to cut corners? Or something else? Just as most pilots don't wake up in the morning and think "I'm going to fly into that mountain", it is reasonable to assume that these people are motivated to do a good job but can't for some reason. Why is that?
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I wrote my last post in the middle of the night (insomnia sucks), and having thought about it since then, I think the bit quoted by @StrandedonEarth may be a bit unfair to Boeing. Clearly Boeing has a responsibility to ensure that the parts that their suppliers provide to them conform to the design, but it sounds from the quote like they are doing that. If Spirit is being deceitful by painting over bad rivets to hide them, that's on Spirit, and good on Boeing's QA for noticing.
We also have to remember that the people assembling parts at a fab shop like Spirit generally aren't licensed aircraft mechanics. They'd be people off the street with only the bare minimum skill set to do the job (probably much of that obtained through on-the-job training). I am generalizing, but I have to wonder how much most of them really care about aviation?
The professionalism I experienced in my colleagues in fleet management at the airline where I worked, on the other hand, was mostly born out of a love of aviation and a talent to get that far in the organization. The mechanics in the team were the best in the company. It was their job to provide troubleshooting guidance to the line mechanics. The chief pilots weren't directly in the fleet management team but fleet management and flight ops worked closely enough together that we were on a first-name basis with them. The engineers had all studied aeronautical or mechanical engineering and were there because they liked airplanes. So it was a much different environment than at an outfit like Spirit.
That said, it would be Boeing's responsibility to install the parts that it gets from Spirit correctly. I don't know if these plug doors are sub-assemblies of a larger fuselage section that's also made by Spirit, or if the plug doors are something that Boeing mechanics install themselves. Either way their processes would need to monitor and ensure that all parts of all assemblies conform to the design. It sounds like Boeing's QA mostly does that, but stuff is somehow still falling through the cracks. The question then is "why?". Are they understaffed and overwhelmed by a flood of poor workmanship by their supplier? Are they jaded and don't care anymore? Something else? I can't know. But we can rest assured that the high profile of this event will yield changes.
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2 hours ago, StrandedonEarth said:
Oh geez, read the whole article, yeah, not flying Boing (deliberate sic) again, not that I plan to fly anytime soon. Dang bean-counters gut everything. The comments are equally damning about MBA "leadership" culture. Another excerpt from the article:
I'm going to trot out my naivete again: How does this happen on the ground, on the factory floor? We once had a competitor's airplane in our hangar while it was being fixed by an Airbus AOG team. It was winter, and in the interest of overall collective aviation safety, we allowed Airbus and the competitor to use our space so the work could be done properly. (Competitor airlines collaborating on maintenance isn't uncommon, because we're all ultimately working towards the same goal.) Our CEO saw the airplane there and had a total meltdown rage fit, complete with contorted face and spittle flying out of his mouth, but the airplane stayed in the hangar for a bunch more days until it was fixed. Everyone just ignored the guy's demand that we kick them out. That's the climate I knew. How has the laziness and corner cutting seeped down from those bean counters to the floor? Something's not right.
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4 hours ago, monophonic said:
It is starting to look like Boeing's management has been making some very big mistakes, in my eyes. And the system is catching up to them finally, I hope.
I am not going to make excuses for Boeing. That wasn't the intent of my post. My post was intended to point out that the people in the industry generally aren't a bunch of "Mr Burns" types, with an array of evil plans. Neither the MCAS nor the door plug issue should have happened, that is clear. But let's not over-simplify those problems (or their solutions) either.
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You know, the media loves to portray the aviation industry as some sort of "heros and villains saga", but that's short sighted and stupid. I have spent most of my engineering career in the industry. And while I grew disillusioned and cynical towards the end, feeling like I was being held hostage by a bunch of Pakleds, the people in the industry are by and large conscientious and good. They are people though. They make mistakes. Pilots make mistakes, mechanics make mistakes, engineers make mistakes, management makes mistakes. But the system, as a whole, is designed to catch those mistakes before they become catastrophic. It does an extremely good job of that. You're far safer riding on a commercial flight than you are driving on the highway. That's not a coincidence. Even in the Alaska Airlines 1282 case, engineering design, pilot training, ATC procedures, etc. came together to yield an outcome where nobody got seriously hurt. That makes it a success story. Should it have happened? No. Given that it did happen isn't it great that nobody got hurt? The backups and backups for backups worked. The industry learned a valuable lesson, and the mistakes are being corrected. That's what's supposed to happen. During my time in the industry, we celebrated the aircraft that we sent to the desert to be turned into beer cans. It was our job to safely get them to that point in their life cycle. Sending them off meant we'd done so.
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10 hours ago, monophonic said:
Mayhaps. I think among other things Boeing acquired this "open door policy" with McDonnell Douglas. See https://en.wikipedia.org/wiki/American_Airlines_Flight_96
And yet the DC10 is, today, regarded as a "brick sh*thouse", structurally. It's extensive use of titanium finger doublers makes it much more fatigue resistant than any of the Boeing or Airbus designs and Airbus still to this day even uses basically the same engine pylon design as the DC10s much maligned engine pylons. The DC10 is more of an example of how an otherwise great airplane can have its reputation tanked by bad maintenance and, subsequently, by people who don't know what they are talking about than an example of a bad airplane. There's a reason you see so many of them flying in cargo operations.
P.S. Before someone says "buh buh buh but!" about the Turkish Airlines flight 981 crash: That was the result of Turkish Airlines mechanics screwing up a mod to the door latch that was mandated after the AA96 incident. (Their error made it easier for the door to be closed improperly, rather than harder, as was intended). And the ensuing AD that mandated installation of blowout panels between the passenger cabin and cargo hold affected all widebody aircraft of the day, from B747s to L1011s to A300s to DC10s. The cargo door failure on Turkish Airlines revealed a design flaw in all widebody types, not just the DC10.
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8 hours ago, ARS said:
Interesting... Does this also applicable for a situation where there's a sudden tumbling of the object that causes significantly increased drag?
I would say no. Surviving re-entry is all about managing the heat transfer rate and controlling where that heat is going. When a vehicle starts to tumble, you lose control of both those things.
As a rough approximation, you could look at the rate of change of the re-entering body's kinetic and potential energy. Most of that is being disipated as heat. Doing that also illustrates why sub-orbital vehicles like Blue Origin's New Shephard and Virgin Galactic's Spaceship One don't experience significant re-entry heating: Their kinetic and potential energy are on the order of 2% of that of an orbital vehicle.
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36 minutes ago, kerbiloid said:
The Ancient Kerbals have written this on the tablets:
I'm ancient, but not yet pining for the fjords...
Also, I incorporated much of that into my rudimentary re-entry heat mod and it worked a lot more believably than the silly re-entry heat that Squad eventually added into the game about 2 years later. I never understood why their model was so bad when better was clearly possible.
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Presumably the shirt and cell phones went out when the cabin pressure equalized with the outside air (this happened when they were above 16000 feet, so the differential was already quite high). Once they were at equilibrium, the speed of the air flowing out would have been much less; more like a skydiving plane. I agree that I wouldn't have wanted to sit by the opening, but "fatal FOD tunnel" is a bit much.
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3 minutes ago, IonStorm said:
- Smallest maneuver 0.1 mm/s;
I can achieve more than that by eating a black bean burrito...
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1 hour ago, AckSed said:
Just look at the stupendous precision of OSIRIS-APEX's interception orbit. Just... look at it:
That final act really is a thing of beauty.
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16 hours ago, tater said:
I missed the specifics I guess. I remembered the alternate seating arraignments, just not that the exact thickness of the trim would have to be different, even for a never seen latch. There's a flush outside latch on the real doors, for example, maybe just that one exists?
The exterior handle is just that: A handle. The hinge mechanism isn't so much a latch as a mechanism to move the door up past the stops and swing it out. Again, it is the stops that hold the door in as the pressurization loads try to push it out.
Also, if you had a closing mechanism hidden behind a fixed panel, how would you ever verify that it remains properly closed? Retain it with bolts? Bolts that could come loose and fall out, allowing the door to come open?
I expect that an Alert Service Bulletin will eventually be released for this, calling for the plug to be wired with proximity sensors and connected to the electronics that monitor the states of all the doors on the aircraft. (I am sure the door monitoring system has an acronym, but avionics wasn't my specialty so I don't know it off the top of my head.) The system is likely already capable of supporting that door. The service bulletin will probably have a deadline for installation of the wiring and sensor(s) of 24 months to allow planning and implementation at a regularly scheduled heavy maintenance opportunity. And if they're worried enough about something coming loose during those 24 months, they will probably also include a requirement for a repeat inspection until the sensors are installed. Alert Service Bulletins aren't automatically Airworthiness Directives (ADs), but I would also expect an AD to follow, mandating that the Alert Service Bulletin be completed.
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5 hours ago, RCgothic said:
Castellated nuts and cotter pins are a *terrible* way of securing a bolted joint. The nut has to have enough clearance to get the pin in which means in practice it can back off a little. Depending on torque and wear it's not unusual to shear the pin entirely. At best this will temporarily retain a nut that's come a bit loose before the bolt fails.
The best way to make sure a nut doesn't come loose is to ensure it's correctly fastened to begin with (and the best way to do that is with a stud puller) and definitely not with a castellated nut.
Yikes.
Castellated nuts are used all over the place in aircraft. This isn't a case of some sort of incompetence. They're typically not used in strucural joints, but they are everywhere on an aircraft. Smaller strucural joints are typically done with Hi-Loks and big structral joints will use suitably torqued conventional bolted joints. The joint in question isn't a structural joint because the bolts just hold the plug in place relative to the stops. The stops carry the structural (pressurization) loads, not the bolts.
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Seems United has found problems with some of the plugs on their aircraft:
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[Pakled]: It is broken, can you make it go?
[Vogon]: Please complete form 127.8(b) "request for form 976.3(a) form" in triplicate...
[Pakled]: ...It is broken, can you make it go?
[Geordie La Forge]: bangs head on desk
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5 minutes ago, tater said:
I know that the NTSB lady in the vid above states that she wants the CVR time lengthened, and for existing aircraft, nit just whatever year they start being longer (cause she said that).
What the NTSB wants is only one side of the negotiation. Please see the NPRM in the US Federal Register for the rule change that led to the current 2 hour requirement. That should give you a sense of the work that was done (and what was considered) to reach the current consensus. The comments responding to that NPRM may also be available online (I haven't looked); they would give you insight into opposing positions. Similar discussions would be required today before the FAA could mandate fleet wide retrofit of CVRs with the type of capabilities you envision.
(I have been involved first-hand in FAA rulemaking processeses. Trust me, it is very bureaucratic... The meetings are T.E.D.I.O.U.S. tedious. ...Imagine a room full of Vogons and Pakleds and you'll be on the right track.)
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8 minutes ago, PakledHostage said:
The standard for CVRs is 2 hours, not 25 hours. The CVR and FDR are two different boxes.
Please help me out here @mikegarrison!? They don't seem to be understanding what I am saying...
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The standard for CVRs is 2 hours, not 25 hours. The CVR and FDR are two different boxes.
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Quite rightly, things aren't done on an ad-hoc basis on aircraft. For example, the BBC reports that the cockpit door flew open when the aircraft depressurized. That happened because, despite being locked and largely impenetrable from the cabin, there are rules that require the door to equalize pressure between the cockpit and cabin when something like this happens (and it has to work both ways, because the catastrophic depressurization could occur forward or aft of the door). Cockpit security was increased post 9-11, but it wasn't just a simple matter of adding better locks. There is no "let's just do this" in aircraft engineering.
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2 hours ago, tater said:
Seems like a law should have specs for the survivability of data recorders, then add that it should make a mirror backup, and up the time to whatever is possible now in the size/power constraints. It's not like SSDs are expensive compared to a data recorder.
It's not that simple. There already are "laws" that mandate what voice and data recorders need to do: The Federal Aviation Regulations (e.g. FAR 25.1457). Changes to those regulations require a whole rulemaking process where industry, pilot associations, etc. get a chance to make their case for why the rule should or should not be implemented. The pilot's unions will inevitably have a lot of negative to say about any new standards that increase the amount of time the CVR stores in its loop, so it wouldn't be a straightforward rule change. The change that increased the CVR recording time to 2 hours was made in 2008 (ref. Federal Register 73 FR 12563 that was published following the Notice of Proposed Rulemaking cited in Federal Register 70 FR 9752)
You also won't be able to buy an off-the-shelf SSD that meets the FARs for crash and post-crash fire survivability (among other requirements). Any new hardware would be expensive, because it would have to be certified by the manufacturer as meeting the relevant updated FARs. That expense would have the industry protesting the cost of the change. It would take a lot of political pressure, time and expense to get changes to CVR recording length through. Two hours is what they managed to push through in the last change. It will be a while before it will ever be increased again.
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Quote
The missing plug door was recovered on Sunday by a Portland school teacher identified only as “Bob” in the Cedar Hills neighbourhood, who found it in his back yard, the NTSB chair, Jennifer Homendy, said, adding that she was “very relieved” it had been found.
It seems that the missing door has been found. I don't have time to look for the press release, but the above quote came from an article in The Guardian (British source).
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14 minutes ago, tater said:
I know squat about it, just seems odd to clear other aircraft without understanding the failure mode. No idea if this is a thing, but what if there was a bad batch of bolts (or even part of a batch—the last 10 bolts in some run were not at spec)? Somehow they don't meet spec, and they snap. Those specific bolts could be on other doors, and look fine, properly tightened, but if you x-rayed them, they'd have some sort of visible flaw.
Over the years, I have stayed out of these discussions and left it to @mikegarrison to comment because he seems to be able to say in 1 or 2 sentences what I try to say in 5-10 paragraphs, but this is what I was beating around the bush about above. The inspections required will depend on what they think the failure mode might be. They might cast a wide netand look at lots of things while they have it open, or they may have a good idea of the failure mode and focus on just that.
They might also call for a progressive inspection where if you find A, you have to do B, but if you don't find A you can close it back up. And if it is something that might recurr, crop up over time or get worse over time, then they'll call for a repeat inspection too.
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39 minutes ago, Shpaget said:
Am I reading this correctly? Plug blows out, AA makes a voluntary decision to ground its entire 737 MAX fleet of 60+ planes, checks 18 of them, declares them A-okay and returns them to service. Then FAA issues EAD and they reground the fleet?
I could see that happening. They try to do the right thing on their own and then the AD comes out that calls for something different than what they did so they need to back and do it again.
In my tenure as a hostage of Pakleds, the mechanics once found serious cracks in a landing gear lug, so we took it upon ourselves to ground the fleet and perform an inspection on all our aircraft of the type before further flight. We then told the regulator and manufacturer what we'd found and what we did about it. Fortunately, they agreed that what we did was sufficient and the resulting AD just said to do what we did, but if they'd have asked for more, we'd have had to ground the fleet a second time.
Edit: Thinking about it some more, it may also be that Alaska Airlines found more problems on more airplanes when they did their inspections and that's what prompted the FAA to issue the emergency AD. In the landing gear crack episode I mentioned above, the mechanics found two incidences of cracking, so we grounded the fleet (it was night time so most of them were on the ground anyway) and called for an inspection. We then told the regulator and the manufacturer in the morning and they took it from there. If Alaska Airlines found more problems on more aircraft when they did their first round of inspections, they would also have notified Boeing and the FAA, and an emergency AD would be the expected outcome.
Boeing 737 Max: the saga continues…
in Science & Spaceflight
Posted
I saw in the CNN article that Alaska Airlines' COO, Constance von Muehlen, was seated in the seat adjacent to the L/H plug door on the first flight that they operated (from Seattle to San Diego). It's a token gesture, but a respectable one.