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> He said the pilot procedure the FAA approved as an interim solution — urging pilots to make sure to turn off the system when icing conditions dissipate to avo
by hn8305823 3y ago
> He said the pilot procedure the FAA approved as an interim solution — urging pilots to make sure to turn off the system when icing conditions dissipate to avoid overheating that within five minutes could seriously damage the structure of the nacelle — is inadequate given the serious potential danger.
This is insane
What are the chances that even a very well trained and experienced major US airline crew would forget to turn of the engine anti-ice within 5 minutes of non-icing conditions? Greater than zero for sure.
- StephenSmith 3y agoHow obvious is it that the plane has entered non-icing conditions?
- sokoloff 3y agoIt's obvious enough. They have a total-air-temp displayed on the FMC and a TAT above 10°C OR not in visible moisture OR SAT* below -40°C is a good enough proxy for "not in icing conditions". The problem isn't knowing whether or not you're in possible icing conditions if you think to ask the question, but rather reliably remembering to evaluate it every single time you enter and exit possible icing conditions. * SAT - static air temp (air temp before the ram rise).
- wkat4242 3y agoThat's not obvious. Something with critical damage potential shouldn't be hidden in a reading in an obscure display page where a value has to be evaluated by several rules. It should be a caution light or something at least.
- sokoloff 3y agoI'm not advocating that Boeing is proposing a sensible path here; I think they're not. But ATPs don't have any trouble evaluating "am I in potential icing conditions?" as they've been doing it for one to many thousands of hours previously.
- wkat4242 3y agoI understand. It's just that most accidents have not just one cause but a whole chain of them. Something small happens that causes the pilots to be distracted trying to fix it, meanwhile ignoring the elephant in the room or forgetting a 'routine check'. The flight deck isn't always a relaxed place and this is when these things can get out of hand so easily. This kind of mistake has been made so often and lives have been paid that I find it crazy that it's still being proposed.
- cratermoon 3y agoIn the "swiss cheese model" of accident causation this design is more hole than cheese.
- cratermoon 3y agoIronic I made this comment just before the incident with the 737 Max getting holed in flight.
- ledauphin 3y agobased on the article, it doesn't sound like this has anything specifically to do with temperature - the issue is more about whether there is moisture in the air. If it were just a temperature thing, you'd think it could be automated, but I don't think that's really the main thing they're dealing with here. In theory this means switching the system off when you exit the clouds. This is usually pretty noticeable, but maybe less so at night, since you might be breaking out into a pocket or a clear layer between other layers, without visibly seeing much of anything outside. I would hesitate to comment on the feasibility of this beyond what the interviewed persons have said, precisely because they're not clarifying (to the readers in any case) what the actual thresholds here are. And the interviewees don't seem convinced that this is a reasonable/safe requirement.
- paulddraper 3y agoObvious from the instrumentation. But easy to forget to check the instrumentation.
- ahoka 3y agoDuring the last MAX fiasco, I said to someone that if there is a button you have to push every five minutes for the plane not to explode, then failing to do so would be “pilot error”, instead of a gross design failure. It turns out this is not a joke…
- RangerScience 3y agoThis is literally a joke on the excellent board game “Space Alert” - someone has to wiggle a mouse every so often or everything on your Sitting Duck Class Explorer turns off.
- zacharycohn 3y agoTechnically the screen saver/lock screen comes on and someone has log back in before anyone can take any actions.
- operatingthetan 3y agoThis is a real thing in modern trains: >The device sounds a warning after 25 seconds of inactivity by an engineer. If the engineer fails to respond to the warning tone within 15 seconds, the system applies the brakes and stops the train. https://www.newstimes.com/local/article/Alerter-system-prevents-engineers-from-falling-6264901.php https://www.newstimes.com/local/article/Alerter-system-preve...
- foooorsyth 3y agoDead man’s (safety) switch
- david422 3y agoOk, I don't know much about trains, but it seems like if they can build this kind of system then they could also build a system that only allows trains to go as fast as track "speed limits".
- TylerE 3y ago
- moffkalast 3y ago[flagged]
- dylan604 3y agoI wouldn't be surprised to find out it is an optional unit like the attack angle sensor for MCAS
- error503 3y agoIn the MCAS case the 'optional' component was an AoA display available to the pilots. Due to a misunderstanding about the design intent, planes without this option also did not display an AOA DISAGREE alert if the sensors disagreed. (I agree that such a simple situational awareness aid based on data the plane already has being a paid option is pretty absurd) However all MAXes did/do have two AoA sensors, and prior to the fixes, regardless of the AoA display option, MCAS only considered one of them.
- eastbound 3y agoIn the MCAS, the ‘AoA disagree’ sign allowed more freight to be carried. The pricing segmentation is based on freight, the intent was not segmentation over security levels. Even if it leaded to lowering security so much that 4 planes crashed in just a few months.
- error503 3y agoThe AOA DISAGREE was never intended to be optional, that was a bug due to miscommunication between Boeing and the avionics manufacturer, if the congressional report is to be believed. Only the persistent numeric AoA indicator was optional. And none of this had anything to do with freight, there's no difference in capabilities between the aircraft, it's purely about pilot situational awareness. https://boeing.mediaroom.com/news-releases-statements?item=130431 https://boeing.mediaroom.com/news-releases-statements?item=1...
- chem83 3y ago
- gopher_space 3y agoSomeone in the article comments said a pilot might be dipping into and out of icing conditions throughout a flight. You'd need to remember each time and if you forget once you'll lose both engines. The latest Tesla features manual window wipers and if you don't use them right the car explodes.
- LegitShady 3y agoWhat does using them right mean?
- roselan 3y agoIf you turn them on when it's not raining, it explodes.
- bluecalm 3y agoIf you forgot to turn them off when it stops raining is more apt comparison except it's easier to detect no rain than no frosting conditions.
- pas 3y agoit seems easy to detect overheating, frost or no frost, no?
- gopher_space 3y agoI think the main issue is that every other plane does in fact detect and handle overheating automatically.
- TylerE 3y agoWhen you’re 6 inches from a continual fireball?
- ldoughty 3y agoSimple. 1. Wait for people to report a problem 2. Inform users that they were doing it wrong, it was always intended for you to do it the other way E.g. how to hold your iPhone.
- wolverine876 3y agoBoeing's main argument seems to be that, even if the pilot forgets, the overall risk isn't worth the remediation: In its petition to the FAA, Boeing argues the breakup of the engine nacelle is “extremely improbable” and that an exemption will not reduce safety. “The 737 MAX has been in service since 2017 and has accumulated over 6.5 million flight hours. In that time, there have been no reported cases of parts departing aircraft due to overheating of the engine nacelle inlet structure,” the filing states.
- jbverschoor 3y agoWho forgot to file the reports?
- falserum 3y agoMail from pacific ocean floor is slow or it’s a separate case?
- WesolyKubeczek 3y ago> “extremely improbable” Read: happens at least twice a week
- dtgriscom 3y ago> no reported cases of parts departing aircraft due to... Wow, that's a great phrase. "No reported cases" is a serious weasel-phrase, and "parts departing aircraft" is much easier to take than "things falling off planes."
- deleted 3y ago[deleted]
- deleted 3y ago[deleted]
- notatoad 3y ago"no reported cases" is a lot less of a weasel-phrase in an industry that has mandatory reporting of these things.
- siva7 3y agoI wonder how the families of the 346 victims must feel reading years later such a headline like "Boeing wants FAA to exempt MAX 7 from safety rules to get it in the air"
- SpicyLemonZest 3y agoProbably pretty worked up, which is why the headline was phrased that way. If they said something like "Boeing seeks safety exemption for MAX 7 anti-ice system", it would communicate more information about the contents, but readers would be less likely to get mad and thus less likely to click.
- siva7 3y agoI'm not sure that the actual content would ease up the situation as a "pilot failure" likely to happen in said procedure would end up catastrophic.
- SpicyLemonZest 3y agoBoeing's argument is that it's not likely to happen, as it hasn't happened in the 6.5 million flight hours with other MAX models for which this procedure is approved.
- kosolam 3y agoWhich don’t have this problem because the material used for the engine pod is metal and not fiber like with the uncertified models. This fiber is breaking up after five minutes of heating
- worik 3y agoGood use of headline editing then
- JohnFen 3y agoMaybe? I like to think that the people affected are paying more attention than others, and aren't stupid. They'd know that "Boeing seeks safety exemption for MAX 7 anti-ice system" means "Boeing wants FAA to exempt MAX 7 from safety rules".
- exabrial 3y agoyou should probably not read the rest of an aviation manual then. You ought to see what happens if you leave an air valve in a certain position too long.
- calamari4065 3y agoI can come up with several methods to solve this problem at the hardware level. Slap a temperature sensor on/in/near the heater Monitor current through the heater for temperature coefficient response Capacitive sensing of ice on the heater A timer that shuts off the heater after some time and a buzzer to alert the crew You could even have a thermal fuse with a manual time-limited override Honestly there's so many easy ways to prevent thermal runaway that creating a situation where THE ENGINE FALLS OFF is inexcusably negligent. My space heater has no less than three independent, redundant safeties. As does my clothes iron, my coffee pot, my slow cooker. It really is not that complicated.
- benhurmarcel 3y agoIt’s not an electric heater, it blows engine core air from the compressor into the inlet lip. And sensing icing on an inlet isn’t as simple as you make it out to be.
- smrq 3y agoSo humans are supposed to be able to do it (within five minutes) with the sensor data already available to them, but it's not easy to make a sensor do it automatically? Maybe this is overly optimistic, but I'm confident they could figure out something if they wanted to.
- calamari4065 3y agoGreat, that doesn't change the fact that there are many ways of ensuring a structure doesn't overhead and explode.
- SoftTalker 3y agoAnd one or more of those is probably going to be the long-term fix. However any change like this also needs FAA testing and certification, and enough design and review to be sure the changes don't introduce other new problems, all of which will take some time.
- pas 3y ago
- epolanski 3y agoNot only that, we talking alredy heavy and tense situations you don't want the crew to give yet another item to check.
- hosh 3y agoBoeing got taken over by McDonnell Douglas business types, and engineering excellence is no longer the main thing there. This seems like how the situation would naturally play out. (I hear from the rumor mill, something similar is happening at Google).
- callamdelaney 3y agoA very brief look at almost any open source google code could tell you that
- tim333 3y agoYeah, all kettles in the UK which start in price from about £8 have a bimetallic strip based device to disconnect the power if the thing tries overheating because it's got no water in or such like. You'd think something like that would not be so hard or expensive to do.
- TylerE 3y agoPlace that kettle on top of a blast furnace and see how easy it is. Remember we’re talking about something attached to an operating jet engine. Edit: Also depending on altitude ambient temperature can vary over a range of several hundred degrees - it gets really really cold at 40,000ft.
- swells34 3y agoTo be fair on both your point and the parent comment, it is both a difficult problem, and one that engineers at Boeing are capable of solving (and likely already solved). The issue here isn't an engineering one, it's a management one.
- tim333 3y agoLooking it up the heating system uses bleed air from the engine so probably isn't as easy to control. On the other hand it just has to stop the thing getting hot enough to damage carbon composite which probably isn't anything extreme temperature wise. If you limited it to say 80C it would probably be ok to stop ice and also not fry the composite.
- deleted 3y ago[deleted]