ANSWERS: 12
  • If everything failed than no, of course not. The landing gear couldn't deploy, the guidance tower couldn't give advice on how to land, and the crew wouldn't know where the fuck they were. Oh yeah, sounds ideal!
  • No...The plane becomes nothing more than an aerodynamic rock...in other words, gravity rules!!
  • A friend of mine is a retired pilot. He told me that large planes (727's, etc) can be landed without power "dead stick" if you will. I don't know much about it, but I'll take his word for it.
  • Without hydraulics, you can not control the plane, look up United DC-10 in Sioux City Iowa. Dead stick is possible if you have control of the engines and flaps.
  • a lot of CONFLICTING ANSWERS there. I am not a pilot so EXCUSE MY IGNORANCE on this topic - but I thought that even if all electronics failed the hydraulics would still function - ie the pilots would be able to manually lower the wheels and glide in to land on a highway for example. need a definitive answer from a pilot on this please. either it is possible or not. it's not rocket science - or is it?
  • ENTIRELY without power, no. There is no mechanical linkage between the stick and the control surfaces and even if there were a mere human would lack the strength to do anything with it. Therefore, if the electrical system dies, so does the plane and (likely) everyone on board. If it were merely the more complex electronics (mostly sensors and instrumentation) that failed then there would be no real problem. The controls are electro-mechanical but relatively simple.
  • Can you please explain briefly how the pilots would land the aircraft? Is it a matter of gliding into a landing or is it more complicated? I have been told that the pilots would not have enough strength to use the hydraulics without electrical assist. I would need some details to explain how the pilots' skill was utilised to land the plane by the skin of their teeth so to speak. Thanks.
  • Yes it can. Research the Gimli Glider. This 767 ran out of fuel and landed at an abandoned air base 60 miles away in 1983 where there was an auto race taking place. They deployed the "ram air turbine" to power the hydraulics. See: http://en.wikipedia.org/wiki/Gimli_Glider
  • Alright I can answer it very simply and expand. Yes they can land. To clarify some issues I will start with electronics. Electronics are powered by the APU and engines, referring to jets, they are equipped with a Ram Air Turbine (RAT), a small propeller that deploys on the belly of the craft and generates enough power for few systems. The plane has their altitude indicator as well as speed, but not flaps, spoilers or gear. Landing gear does however have enough weight for a powerless drop if they are above a certain altitude (2500 ft i think). As well, the pilot has control of the stick and can essentially steer the plane, but can't ultimately control distance as much as is most often required. To answer about Hydraulics, they are controlled by electronics. when you push a button for a hydraulic system, it is not interpreted because systems are off. As well if a typical passenger jet is gliding, they decend at an appx rate of 18.5 km per 1000 meters. To answer someone elses post, the space shuttle does not land with no power, it does glide, and does not have a main jet engine running but it has RCTs (reaction control thrusters) as well as thrust stabilizers that are controlled by the very active electronics suite. Don't confuse power loss with engine use.
  • jets without power are rocks in the sky. they nose over and crash into the ground. they are so heavy that gliding is not possible. thats why they have jets on the wings and or on the tail.
  • Yes, they can land without power....most aircraft have very high glide ratio's ..for example I believe a 737 will travel horizontally for 13 feet for every foot it drops in elevation...the weight of the aircraft has little to do with the glide ratio....provided the crew can manually deploy the landing gear by manually overriding the hydraulic system it can be done....
  • It's not a simple yes/no answer. Not all aircraft have the same sort of systems, so the answers will vary. In an attempt to limit the confusion, I'll deal with the 767 and 747-400 only. If a 767 were to lose both engine driven generators, they should be able to start the APU and to get electricity from its generator. If that doesn't work, limited electrical power is provided by hydraulically driven generators, that will automatically come online when the main generators drop off line. If the engine driven generators, APU generator, and the HMGs don't work (not a good day, as that's six different sources), then you will be restricted to battery power. Battery power will last for at least 30 minutes, and perhaps up to about 90, but provides very limited functions. In this scenario, the engines will continue to work (the don't need electricty at all once running), as will the hydraulics. Lots of things won't work, but you may be able to land ok, as long as you do so before the batteries run out. The 767 has a ram air turbine, but that does not provide any electrical power. The 747 has four generators. Again, with loss of all four, you'll be back to battery power, with the same 30 to 90 minutes until it all goes dark. The 747 APU can't be started inflight, so that doesn't provide any further backup. In daylight, and clear of cloud, the aircraft could still be flown with no electrics at all, but you would not be able to lower flaps or landing gear. Control loads would be normal, but the trim could not be adjusted.

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