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Fly-By-Wire Flight Controls
Suppose a smaller airplane with it's fly-by-wire controls goes runs out
of fuel. All the engines quit. On a larger jet a ram air turbine would drop into the airstream and power the controls. How does it work on smaller planes like the Dassault Falcon or the F-16? Alternatively, I've always wondered if one could not keep a special reserve tank for the APU. When the engines quit, the APU automatically starts to power the controls. Would such a system be safe and would it be certifiable? Would it weigh less than the existing system? -Charles Talleyrand |
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Fly-By-Wire Flight Controls
"Charles Talleyrand" wrote in message oups.com... Suppose a smaller airplane with it's fly-by-wire controls goes runs out of fuel. All the engines quit. On a larger jet a ram air turbine would drop into the airstream and power the controls. How does it work on smaller planes like the Dassault Falcon or the F-16? Alternatively, I've always wondered if one could not keep a special reserve tank for the APU. When the engines quit, the APU automatically starts to power the controls. Would such a system be safe and would it be certifiable? Would it weigh less than the existing system? -Charles Talleyrand On the A-6E and EA-6B aircraft, the Emergency Ram Air Turbine (RAT) only powers the Emergency DC Bus which in turn provides power to a small set of essential instruments. It does not provide any hydraulic power for the flight controls. |
#3
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Fly-By-Wire Flight Controls
Charles Talleyrand wrote:
Suppose a smaller airplane with it's fly-by-wire controls goes runs out of fuel. All the engines quit. On a larger jet a ram air turbine would drop into the airstream and power the controls. How does it work on smaller planes like the Dassault Falcon or the F-16? The same way on a BAE Hawk. Alternatively, I've always wondered if one could not keep a special reserve tank for the APU. When the engines quit, the APU automatically starts to power the controls. Would such a system be safe and would it be certifiable? Would it weigh less than the existing system? Some years ago there was an Airbus A330 FBW fly by wire widebody that ran out of fuel crossing the atlantic. It had to make an emergency landing at (I thnk) the Azores I think from over 100km out without fuel. A leaking fuel delivery pipe in the engine pylon drained the aircrafts fuel: the pilot didn't believe his instruments and thus kept transfering fuel from the good side to the bad side rather than shutdown the bad engine. He thus drained both wings. When fuel cut out (I saw a dramatisation ogf the events) the ram air turbine deployed and the pilots, after finally acknowledging their fuel situation went through their checklist. Lights and pressurisation was lost with the power. Most pointedly they lost spoilers and flaps; they really only had a few instruments, ailerons, tail surfaces and the undercarriage. As a result of being without flaps the landing speed was very high and becuase there were no spoilers they couldn't loose speed or altitude and actually had to circle and zig zag to loose both speed an altitude. This made the one chance of making the runway even harder as there would be no go arounds. To cap it all of the runway in the azores ends in a 300ft shear cliff. They stopped a few dozen meters short with blown tyres. Airbus changed their software and though the pilot was clearly not making the best decisions that day it was easier to given him awards. The ram air turbine provides very little power. I think the idea of giving the APU its own reserve fuel supply is tempered by the fact that it is perhaps better to keep the engine lit for a few seconds longer. Perhaps a cartriedge or two of of rocket-gas generator turbine could be used to provide pressure for flap and spoiler deployment |
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Fly-By-Wire Flight Controls
Perhaps a cartriedge or two of of rocket-gas generator turbine could be
used to provide pressure for flap and spoiler deployment Why not just load more fuel. It would not weigh any more and would be far less complicated. Also have sirens which screech at the pilot. |
#5
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Fly-By-Wire Flight Controls
Charles Talleyrand schrieb:
Suppose a smaller airplane with it's fly-by-wire controls goes runs out of fuel. All the engines quit. On a larger jet a ram air turbine would drop into the airstream and power the controls. How does it work on smaller planes like the Dassault Falcon or the F-16? The Panavia 200 Tornado has a EPS battery (one shot battery) that in case of double engine out situations supplies a few instruments and an electric pump to have some hydraulic pressure. This allows maintaining control over the a/c for ~5-7 (max 10) minutes. Alternatively, I've always wondered if one could not keep a special reserve tank for the APU. When the engines quit, the APU automatically starts to power the controls. Would such a system be safe and would it be certifiable? Would it weigh less than the existing system? I a lot of airplanes the APUs (resp. their intakes and exhausts) are mounted in a way that they can't be used inflight. Besides that, if there still is fuel in the tanks it's better served for keeping the engine alive than just the APU... Benjamin |
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Fly-By-Wire Flight Controls
"Eunometic" wrote in message ups.com... Some years ago there was an Airbus A330 FBW fly by wire widebody that ran out of fuel crossing the atlantic. It had to make an emergency landing at (I thnk) the Azores I think from over 100km out without fuel. 70nm at 34,500 ft A leaking fuel delivery pipe in the engine pylon drained the aircrafts fuel: the pilot didn't believe his instruments and thus kept transfering fuel from the good side to the bad side rather than shutdown the bad engine. He thus drained both wings. When fuel cut out (I saw a dramatisation ogf the events) the ram air turbine deployed and the pilots, after finally acknowledging their fuel situation went through their checklist. Lights and pressurisation was lost with the power. Most pointedly they lost spoilers and flaps; they really only had a few instruments, ailerons, tail surfaces and the undercarriage. As a result of being without flaps the landing speed was very high and becuase there were no spoilers they couldn't loose speed or altitude and actually had to circle and zig zag to loose both speed an altitude. This made the one chance of making the runway even harder as there would be no go arounds. To cap it all of the runway in the azores ends in a 300ft shear cliff. They stopped a few dozen meters short with blown tyres. Airbus changed their software and though the pilot was clearly not making the best decisions that day it was easier to given him awards. Airbus did not change their software which had behaved correctly, they re-issued the flight manuals emphasizing the advice that was already present to close the cross feed valves in the case of unexpectedly high fuel consumption on one engine. Transport Canada fined the airline C$250,000 (about US$165,000) for maintenance infractions relating to an improper installation of a hydraulic pump on an engine of the incident aircraft. Keith ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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Fly-By-Wire Flight Controls
The F-16 uses a Hydrazine/Platinum (IIRC) APU to generate electricity.
Les "Charles Talleyrand" wrote in message oups.com... Suppose a smaller airplane with it's fly-by-wire controls goes runs out of fuel. All the engines quit. On a larger jet a ram air turbine would drop into the airstream and power the controls. How does it work on smaller planes like the Dassault Falcon or the F-16? Alternatively, I've always wondered if one could not keep a special reserve tank for the APU. When the engines quit, the APU automatically starts to power the controls. Would such a system be safe and would it be certifiable? Would it weigh less than the existing system? -Charles Talleyrand |
#8
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Fly-By-Wire Flight Controls
Glide speed generally provides sufficient windmill RPM on the engine(s) to
provide sufficient hydraulic power so that the controls (they don't have to be fly-by-wire, any irreversible hyd flight control system is effected) have sufficient pressure and volume to operate normally with moderate control inputs. R / John "Charles Talleyrand" wrote in message oups.com... Suppose a smaller airplane with it's fly-by-wire controls goes runs out of fuel. All the engines quit. On a larger jet a ram air turbine would drop into the airstream and power the controls. How does it work on smaller planes like the Dassault Falcon or the F-16? Alternatively, I've always wondered if one could not keep a special reserve tank for the APU. When the engines quit, the APU automatically starts to power the controls. Would such a system be safe and would it be certifiable? Would it weigh less than the existing system? -Charles Talleyrand |
#9
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Fly-By-Wire Flight Controls
On 14 Dec 2005 22:43:21 -0800, "Charles Talleyrand"
wrote: Suppose a smaller airplane with it's fly-by-wire controls goes runs out of fuel. All the engines quit. On a larger jet a ram air turbine would drop into the airstream and power the controls. How does it work on smaller planes like the Dassault Falcon or the F-16? F16's have a EPU, and according to this link http://www.f-16.net/f-16_forum_viewtopic-t-1056.html you've got around 10 minutes in Hydrazine mode, to find a nice piece of concreet. After those 10 minutes it's gonna be a membership of the Martin Baker Fanclub. greetz Mu |
#10
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Fly-By-Wire Flight Controls
"Mu" wrote in message
... F16's have a EPU, and according to this link http://www.f-16.net/f-16_forum_viewtopic-t-1056.html you've got around 10 minutes in Hydrazine mode, to find a nice piece of concreet. After those 10 minutes it's gonna be a membership of the Martin Baker Fanclub. Love the reference to Baker!!! |
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