PakledHostage

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.

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.

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.

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.

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.

I can achieve more than that by eating a black bean burrito...

That final act really is a thing of beauty.

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.

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.

Seems United has found problems with some of the plugs on their aircraft: https://twitter.com/cnnbrk/status/1744473546070344134

[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

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.)

Please help me out here @mikegarrison!? They don't seem to be understanding what I am saying...

The standard for CVRs is 2 hours, not 25 hours. The CVR and FDR are two different boxes.

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.

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.

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).

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.

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.

My experience is from a long time ago and my aging brain may also have forgotten some details, but as I recall, the Boeing doors are all plug doors. (At least that's true on the bigger Boeings that were my purview.) The mechanism brings the door in and then down onto the stops on the fuselage. Pressurization loads are resisted by the stops, not by the latches and, those pressurization loads push the doors closed more tightly. The doors are rigged so that all the stops are loaded equally. Boeing has built a lot of doors on a lot of airplanes over the decades. This isn't something new and novel. I am not going to speculate about what failed on this door, but I would be surprised if it turns out to be something out of left field. The AD doesn't specify what inspections should be done, but I expect that they'll remove the plug, do some NDT inspections on the stops and then double check the rigging and that the plug is properly retained when it is unpressurized. (Because, again, the ones I am familiar with are designed to seat more firmly as the aircraft is pressurized, and if they're properly positioned, they wont go anywhere once loaded). The mandate may also require repetitive inspections at some interval that can be done in the course of normal maintenance (e.g. A-check intervals) once the first round of "before further flight" inspections are completed.

I am not trying to suggest that this incident isn't news. I am also not trying to downplay the seriousness of the evident manufacturing/quality control defects. What I am trying to say is that the industry and its regulatory partners generally do an excellent job of ensuring high levels of safety. Lots of stuff happens that doesn't make the news. Some of that stuff that doesn't make the news even makes industry insiders go "holy crap, that was close!" (a certain runaway horizontal stab trim event springs to mind). But what's tiring in cases like yesterday's are the people with an axe to grind (or who are seeking their own 15 minutes of fame) who come out of the woodwork to make hay out of the incident. That does nobody any good. Edit: I should add that the runaway horizontal stab trim incident I am thinking of happened on an Airbus, not a 737 Max. The Max didn't exist yet at the time.

For context: In my former life as a hostage of certain Pakleds, we had two cases of engines puking out their guts over the arctic. The fuselage and empennage were peppered with shrapnel, puncturing holes and necessitating single engine diversions to remote airports. The incidents were arguably equally or even more serious than this Alaska Airlines incident (it also resulted in an emergency AD), but it didn't make the news. As a result, there weren't any so called "experts" bleating about the type being unsafe. The industry did the inspections of the affected engines and moved on. That's how the system works and it generally does so quite well.

Emergency Airworthiness Directives happen to all types. People love to bash on the 737 Max (and some of it is warranted), but grounding of a fleet for a quick round of inspections isn't unique to that type. It happens with some regularity; it just usually isn't this public.

I understand that bovine excrement works well... Also, while I am here, I saw this article in my feed this morning: https://www.nasa.gov/general/electro-luminescently-cooled-zero-boil-off-propellant-depots/ Might be a solution for the boil-off expected for some of SpaceX's orbital fuel depot aspirations?

The Nice model of the solar system's early evolution includes major changes in Uranus and Neptune's orbits, but this involved the two planets interacting with millions of other bodies and exchanging energy with those. In the process, they also "cleaned up" the early solar system and swapped positions.