Boeing 787's Emergency-Power System Likely Active Before Air India Crash (wsj.com) 70
Investigators believe Air India Flight 171 had an emergency-power generator operating when it crashed last week, raising questions about whether the plane's engines functioned properly during takeoff. WSJ: The preliminary finding [non-paywalled source], according to people familiar with the probe, gives investigators a new line of inquiry as they study a crash that killed all but one of the plane's passengers. In all, at least 270 people died following the crash, including some on the ground in the western Indian city of Ahmedabad.
The emergency system is known as a ram air turbine. It is a small propeller that drops from the bottom of the 787 Dreamliner's fuselage to serve as a backup generator. Engines normally produce electricity for an aircraft and help run its flight-control systems. The power generated by the RAT can enable crucial aircraft components to function. The system can deploy automatically in flight if both engines have failed or if all three hydraulic system pressures are low, according to an airline's Boeing 787 manual reviewed by The Wall Street Journal.
It can also deploy if cockpit instruments lose power or problems emerge with the aircraft's electric motor pumps. Pilots can manually deploy the RAT if needed. The most common occurrence is when a pilot thinks that both engines failed, according to Anthony Brickhouse, a U.S.-based aerospace safety consultant. Engine failures can result from a variety of causes, including bird strikes or problems with fuel.
The emergency system is known as a ram air turbine. It is a small propeller that drops from the bottom of the 787 Dreamliner's fuselage to serve as a backup generator. Engines normally produce electricity for an aircraft and help run its flight-control systems. The power generated by the RAT can enable crucial aircraft components to function. The system can deploy automatically in flight if both engines have failed or if all three hydraulic system pressures are low, according to an airline's Boeing 787 manual reviewed by The Wall Street Journal.
It can also deploy if cockpit instruments lose power or problems emerge with the aircraft's electric motor pumps. Pilots can manually deploy the RAT if needed. The most common occurrence is when a pilot thinks that both engines failed, according to Anthony Brickhouse, a U.S.-based aerospace safety consultant. Engine failures can result from a variety of causes, including bird strikes or problems with fuel.
Re:Boeing (Score:5, Insightful)
That's because you've normalised every other risk in your life and can't understand the risk you face in this case. You're still far more likely to die on your drive to the airport than you are in a plane accident, even if you assume every plane in the world was made by Boeing.
Re: Boeing (Score:1)
Re: Boeing (Score:1)
What if I'm such a statistical outlier that your statistics about people that don't drive as carefully as me don't apply?
Re: Boeing (Score:2)
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Will you tell yourself that when you get t-boned by someone running a red light, that you are in control? Does it matter having control when you die? Will you care about it afterwards?
I'm statistically very unlikely to die in relation to the greedy corporation you mention.
Re:Boeing (Score:5, Informative)
Why aren't [Boeing] considered serial killers? They meet the definition 100%
Meh. Boeing's recent safety record is worse than Airbus's [statwonk.com], but flying with either of them is still significantly safer than driving a car, which nobody thinks twice about doing.
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Internal Boeing emails regarding the 737 Max https://www.theguardian.com/bu... [theguardian.com]
“I don’t know how to refer to the very very few of us on the program who are interested only in truth”
“Would you put your family on a MAX simulator trained aircraft? I wouldn’t.”
“No.”
Re:Boeing (Score:4, Interesting)
Re: Boeing (Score:2)
To be fair to them, the 787 has up until now not had a hull loss accident, and this plane was a long way out of the factory (it was more than a decade old). Iâ(TM)d bet reasonably heavily that this was caused by something to do with the fuel they loaded at the airport, but thatâ(TM)s pretty rampant speculation.
That said, good god, the 737 and anything made recently, I agree with you completely.
RAt and most likely APU as well (Score:3)
It's likely that the APU also was activated since the air intake for the APU was found open on the tail. It could of course opened during the crash.
The RAT is as far as I know automatically deployed for a number of reasons and that's something the maintenance techs have to take into account since it means that if you are unlucky you can get hit in the head with it. One of the reasons is a dual engine failure.
So then the problem is to figure out what would cause both engines to fail. This could be a single point of failure situation - something you want to avoid on mission critical systems.
The flight data recorders will hopefully provide a good answer.
Re:RAt and most likely APU as well (Score:4, Funny)
It's likely that the APU also was activated
Thank you! Come again!
Blancolirio pointed it out (Score:2)
Re: Blancolirio pointed it out (Score:1)
No. You couldn't and he didn't.
What went down was:
A few days after the crash, he pointed out that you could hear the RAT just before the crash blossoms [wiktionary.org].
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You totally parsed his sentence wrong. What you said is exactly what he said.
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Boeing's management (Score:1)
Re:Boeing's management (Score:5, Insightful)
Air India is not noted for its excellent technical chops either, and this is the first fatal crash of a 787 *ever* in the plane's 14 year service history. I think we need to wait until the results are in.
Re:Boeing's management (Score:4, Interesting)
Air India is not noted for its excellent technical chops either
In what way? They had a perfect safety record prior to this incident, one that in statistics and ratings were shared with the top western flag carriers. They may not have had a high level of customer satisfaction, but that hardly has anything to do with their technical capability.
Can you cite a poor technical rating they've received?
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That's the kind of thing that happens when a technology company is not run by engineers but by stupid, ignorant MBAs - and may apologies for the pleonasm.
In this case, given India's history of running air craft, railroads, and other mass transportation, I'm thinking it has little to do with Boeing and more to do with maintenance cycles. It's been reported that someone (unclear if it was maintenance or a random passenger) was taking pictures to document wide spread electrical failures in the passenger cabin on the flight prior to the crash. Which is not to say that Boeing isn't blameless, nor that in my opinion that their "leadership" has serious issues and f
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CTRL + F > 'scarebus'
I am mildly disappointed.
Another video going around... (Score:5, Interesting)
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The weight and balance of the aircraft (including fueling) is recorded and will be available to investigators. There's zero evidence so far that the plane was "overloaded" as you say. I've not heard any aviation expert so much as insinuate that this might have been the case or even a possible cause. Besides that it doesn't fit with the evidence. A compressor stall is very loud and would have been heard in the video, and does not usually cause a complete flameout. Usually it's flames, popping sounds, an
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But those calculations are tricky, and international flights are commonly slightly overloaded. This is why dump fields exist. As you never want to land with a lot of fuel still onboard.
Tell me you don't know what you're talking about without telling me you don't know what you're talking about--international flights are not "commonly slightly overloaded." Cargo and passengers are routinely moved around or offloaded when weight and balance limits are not met.
With regard to dumping fuel, it's because max takeoff weights on large aircraft are higher than max landing weights (because the forces on e.g. landing gear are higher when landing than they are when taking off).
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For some planes the Maximum Take Off Weight (MTOW) is quite a bit greater than the Maximum Landing Weight (MLW). These planes will (typically) have the ability to dump fuel to get down from MTOW to MLW more quickly if necessary.
Some planes, however, have a MLW that is not much (or perhaps any?) less than MTOW and don't have the ability to dump fuel - presumably in most cases enough fuel will have been burned by takeoff, climb, and going through checklists before landing (and perhaps circling a bit to use fu
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My money is on slightly overloade
My money is you don't have a clue what you're talking about. If that were actually the case the investigation would be concluded by now. This stuff is comically trivial to prove.
But don't let professions with access to mountains of data and experience get in the way of your armchair video analysis.
As you never want to land with a lot of fuel still onboard.
Fortunately they weren't landing, they were taking off. The fact you mention landing just reinforces that you have no clue what you're talking about.
But those calculations are tricky
They are not tricky in the slightest.
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If you are a 787 pilot then I'll believe you about the wing tips.
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Actually weight and balance of the checked baggage and fuel are recorded. Everything else - including passengers, crew, and carryons is using an average weight.
There have been many accidents caused because the self loading cargo doesn't obey the average - e.g., flights involving military personnel who may be wearing heavier than average clothes, plus be of a stockier build, and having carry ons of their equipment, etc. It's also why the FAA has both winter and summer averages to use.
So while the weight and
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Not completely, just somewhat. And while it is a concern for small aircraft, a 787 is large enough to be quite forgiving about that. Any mainline airliner is, most likely.
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The description in the summary really sounds like some sort of massive electrical short. Of course deploying an additional emergency generator won't fix that, but it's automated. Even with both engines functioning, losing the electronic controls and flying completely manual would be completely different than normal control. There wouldn't be a lot of time to react at such a low altitude either.
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Combine that with video of the plane shortly after takeoff showing those wing tips HIGH in the air.
Can you quantify how that might be a problem? ie "The wing tips were 3 feet higher than normal limits." From what I know, many parts of the 787 like the wings are made of composites like carbon fiber. The wings appear to bend more than on the 787 than on the older 777 which used traditional aluminum alloys. The new 777X will have composite wings and will bend more.
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composite winds bend lot more than aluminum ones, in fact, they probably should have been more bending if everything was fine, that "low" bending in the 787 hints lack of liftt power. This caused the plane to fail to ascend enough and end crashing. What cause this is what experts are researching
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Amateur speculation is pretty pointless, and you by your own admission don't know even the very basics of the aircraft type in question.
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The whole slashdot story is pretty pointless, even. We can just wait a few weeks until expert reports surface in the press. Once we know, we come back here and debate technical issues. Or if experts can't tell then we start speculating. In any case for now it's pointless to discuss with limited understanding of the field and zero technical data.
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Re:Another video going around... (Score:4, Interesting)
I would take that video with a huge grain of salt. The electrical systems do not work unless the main engines are on, the APU is on, or the system is attached to ground power. Sometimes the pilots shut off the main engines without turning on the APU because the ground team will hook up ground power. In the time between that shutdown and hookup without the APU running, the plane will not have electrical power to the cabin. Ground power may just be used for cooling and engine starting if the APU is not running. i don't know what the general practice is, but the APU generates a lot of heat and may not be desirable on a 110 degree day.
There is a temperature limit at which an airplane can take off with a particular grade of jet fuel. If the fuel temperature sensors were reading unsafe temperatures before takeoff, the plane would never have left the gate. If there was a problem with vapor lock, it would have occurred at the very last moment before the engines failed without warning. No pilot would knowingly take off with dangerously high fuel temperatures risking vapor lock. There has to be another contributing factor to cause the fuel flow to the engines to shut off. In the video you can see the exhaust cut off when the wings start to lose lift. To me it looks like the engines were suddenly starved of fuel for some reason, and vapor lock can happen in both engines at the same time for the same reason (boiling fuel). Other failures like fuel pumps shutting off are not a factor due to redundancies.
All speculation (Score:3)
I'm sceptical.
Re:All speculation (Score:5, Informative)
There are other videos taken from the same distance away of aircraft making emergency landings with the rat deployed and it's a very distinct, and very loud sound, just like in the Air India video. Plus you can even see in the video that the RAT is deployed. This is corroborated by the lone survivor who said he heard a very loud bang and then the lights flickered. The RAT deploying makes a very loud bang as is just as he described.
Futhermore there's no sound of the engines. The first thing pilots do when the plane is experiencing a loss of lift at that stage of the flight is TOGA. Yet there was no sound of engines trying to spool up, and no smoke, no flames, no loud pops from a compressor stall. It's 100% clear the airplane had no power from either engine. the only question is why?
Other things we know about the aircraft are that the slats were deployed, and from the video footage we can tell the flaps are lowered to a takeoff position. So the plane was properly configured for climb. Also in the video the landing gear is shown in the toe down position (default deployed position is toe up), which means the pilots had pulled the gear up lever. Perhaps the gear had started to come up and then fell back down again when the power was lost. In any event there's no way to move the gear to a toe up position except to pull the gear up lever.
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Sorry I got that last sentence wrong. There's no way to move the gear to a toe *down* position except by raising the gear.
Some good explanations of this come from garybpilot on youtube, as well as Captain Steeeve (who is a 777 captain).
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Steeeve has been spouting nonsense, blaming the pilots without having any concrete evidence. Then his next video suddenly comes up with "oh, new evidence, the RAT deployed" even though there had been reports of this within hours of the crash.
He has zero credibility at this point.
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No he hasn't. You've obviously not listened to him. He has never once blamed the pilots. Not once. He simply gave the possibilities, including pilot error. But he's always been careful to never point the finger at them.
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Not just the sound. You can see the RAT deployed in the video.
https://www.youtube.com/watch?... [youtube.com]
Speculation (Score:2)
All of this is speculation except for what you could see: a 787 crashing with the RAT deployed. Audio from people videoing the crash doesn't have the sound of the engines spooling up to max thrust. Something or someone seriously was screwed up. Anything, including Boeing and Air India, is rash.
Let the investigation come to a preliminary state after examination of the flight data and cockpit recorders.
Pilot Suicide (Score:1)
My money is on someone in that cockpit pulling the fuel cutoff levers. Modern jet engines do not just stop running. And danm sure not two of them at the exact same time. If something had happened to them there would have been some visual artifact of that. There wasnt they just shut down and that has never happened in any jet ever.
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Could have been a bird strike. That sort of accident HAS stopped both engines of a jet before. https://en.wikipedia.org/wiki/... [wikipedia.org]
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with bird strikes that is not instant on both engines. Not to mention they would be smoking their asses off cause all the unburned fuel in them. Bird strikes in engines are not just a clean shutdown they blow parts of the engine out the ass for mile. That runway would have been littered GENX engine parts.
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It looks like a bird strike has been ruled out. https://www.moneycontrol.com/n... [moneycontrol.com]
Pilot suicide or sabotage seems to be becoming *more* likely. So OP may be right.
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yea for a few minutes. but in this case just do as there got airborne nothing any one could have done to save.
Were they Rolls Royces or the General Electrics? (Score:1)
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Does anyone know what type of engines were on the 787? There are apparently two options - Rolls Royce or General Electric. Both big efficient turbofans. The differences may matter.
GEnx (according to the reports). GE Aerospace has reported that they will be participating in the investigation (India has the lead in the investigation).
On the 787 the flight data recorder (the black boxes, which are, of course, bright orange) collects a lot of data. It seems likely that the what, when, and why will be able to be determined, although it will probably take longer than some would like (and until then, there will be a lot of conjecture, and probably a few conspiracy theories).