Earlier quoted context omitted.
3 including the APU
4 including the Ram Air Turbine (RAT)
The RAT is an expensive windmill, not an engine.
Ocean Microphones May Have Recorded Lost Malaysian Jet's Crash
21–30 of 42 posts
Re: Ocean Microphones May Have Recorded Lost Malaysian Jet's Crash
#22Earlier quoted context omitted.
The APU on a 777 provides truly negligible trust; the exaust from the APU is on the left side, not centered, so if it were providing meaningful thrust it would inducing a yaw moment.
I think the point is that it draws fuel which reduces the endurance by a small amount
I'm pretty sure the generally accepted meaning of an 'engine' in the context of powered flight is 'a thing that provides thrust' and not 'anything that consumes fuel'
Re: Ocean Microphones May Have Recorded Lost Malaysian Jet's Crash
#23With all those satellites in the air, they should able to trace it.
Re: Ocean Microphones May Have Recorded Lost Malaysian Jet's Crash
#24Earlier quoted context omitted.
The APU on a 777 provides truly negligible trust; the exaust from the APU is on the left side, not centered, so if it were providing meaningful thrust it would inducing a yaw moment.
I think the point is that it draws fuel which reduces the endurance by a small amount
The APU is for electric power on the ground, it is not used in flight.
Re: Ocean Microphones May Have Recorded Lost Malaysian Jet's Crash
#25I'm surprised that no mention was made of the U.S. Navy's network of hydrophones (SOSUS) and whatever took its place in the late 1990s. SOSUS was quite successful at detecting a number of Russian submarines since the 1950s with every new generation thereof. In any event, I can only imagine that there would be U.S. government resources (military and otherwise) that could have provided some surveillance information on…
I wonder how much information, if any, is withheld by military organizations in various countries. I presume a particular country doesn’t want to give away their latest radar capabilities or what have you by disclosing tracking information whether it’s through satellite systems or through sub-ocean sonar.
> I wonder how much information, if any, is withheld by military organizations in various countries.
Ooh, I can answer that. All of it, unless forced to disclose by political factors. There is no upside to the military to releasing anything, ever.
HN is a geekfest, and I'm a geek too. I could not, and still cannot, comprehend how resistant to the "helpfulness instinct" a military man is. I, by my very nature, cannot resist helping people whereever i can, and offering whatever information I might judge useful whenever I can. The military [1] is the exact opposite of that. It's hard to get your head around.
I have zero doubt that one or more militaries in the area, especially Singapore, know exactly where MH370 went, or at least what direction it eventually took off in. Every radar in the world is recording 24/7. They have no incentive whatsoever to divulge what they undoubtably know. We'll find out in a few decades, probably.
[1] and many large corporations.
Re: Ocean Microphones May Have Recorded Lost Malaysian Jet's Crash
#26Earlier quoted context omitted.
I wonder how much information, if any, is withheld by military organizations in various countries. I presume a particular country doesn’t want to give away their latest radar capabilities or what have you by disclosing tracking information whether it’s through satellite systems or through sub-ocean sonar.
You don't have to disclose capabilities in a press release honestly unless you really, really need to convince people that you're not falsifying the information or trying to mislead people - there is almost no incentive I can think of to mislead people on a general civilian search mission though. A government could simply point some lowly persons to the general area without any explanation of its methods, put almost…
> it could relieve a great deal of pain and suffering
I confess I don't understand this. The families know how their loved ones died, when, and sort of where (in the ocean). How does knowing the precise location help any?
Re: Ocean Microphones May Have Recorded Lost Malaysian Jet's Crash
#27Earlier quoted context omitted.
I think the point is that it draws fuel which reduces the endurance by a small amount
The APU is for electric power on the ground, it is not used in flight.
...except in emergency situations. Starting the APU was one of the first things they did during the “Miracle on the Hudson” incident IIRC. It’s conceivable that some in-air emergency happening prior to the loss of communication would have required starting it as a checklist item.
EDIT: I just wanted to add that aside from electrical power, it provides bleed air necessary to start the engines, run de-icing (also run A/C packs, operate toilets, etc.) —Hence its usefulness in an emergency situation.
Re: Ocean Microphones May Have Recorded Lost Malaysian Jet's Crash
#28Earlier quoted context omitted.
I think the point is that it draws fuel which reduces the endurance by a small amount
The APU is for electric power on the ground, it is not used in flight.
In some unusual scenarios the APU may be used during flight. If one of the engine's generators fails the APU might be used to help provide power, and below some altitude the APU in the 777 can provide additional bleed air.
In the 777 the left and right hydraulic systems are powered by the left and right engines, but the center hydraulic system has electric and pressurized air driven pumps that I believe can be run off the APU: http://www.flight-mechanic.com/wp-content/uploads/2017/11/12...
If MH370 lost engine power, maybe it was using the APU to keep the control surfaces active? Who knows. In that sort of situation the 777 would be a glider though.
Re: Ocean Microphones May Have Recorded Lost Malaysian Jet's Crash
#29Earlier quoted context omitted.
The APU is for electric power on the ground, it is not used in flight.
...except in emergency situations. Starting the APU was one of the first things they did during the “Miracle on the Hudson” incident IIRC. It’s conceivable that some in-air emergency happening prior to the loss of communication would have required starting it as a checklist item. EDIT: I just wanted to add that aside from electrical power, it provides bleed air necessary to start the engines, run de-icing (also run A…
[deleted]
Re: Ocean Microphones May Have Recorded Lost Malaysian Jet's Crash
#30Earlier quoted context omitted.
You don't have to disclose capabilities in a press release honestly unless you really, really need to convince people that you're not falsifying the information or trying to mislead people - there is almost no incentive I can think of to mislead people on a general civilian search mission though. A government could simply point some lowly persons to the general area without any explanation of its methods, put almost…
> it could relieve a great deal of pain and suffering I confess I don't understand this. The families know how their loved ones died, when, and sort of where (in the ocean). How does knowing the precise location help any?
I think the rituals around death aren't complete without a story. It's the reason why before they tore down the eastern span of the Bay Bridge that let the families of people that died on the bridge visit the spot where they died.