Simviation Forum - can you fly a 747 on only 1 or 2 engines?

Jan 26^th, 2005 at 8:59am

AlphaBravo Offline
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as the title says i wanted to know

Craig

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Reply #1 - Jan 26^th, 2005 at 9:28am

commoner Offline
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Quote:

as the title says i wanted to know

Craig

.....Fly?..Yes, straight to the scene of the crash would be my guess. commoner;D

"In theory, there is no difference between theory and practice. But, in practice, there is."

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Reply #2 - Jan 26^th, 2005 at 9:41am

Hagar Offline
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Depends what you mean by fly. I'm not sure about maintaining height on 1 or 2 engines but the 747 makes a pretty good glider. This was proved on one occassion when a BA (I think) 747 full of passengers flew through a huge cloud of volcanic ash. This stopped all the engines but it glided for several 100 miles I believe before they were able to restart them. I seem to remember them saying at the time that the glide ratio was as good as some sailplanes.

I found this which might throw more light on the subject. http://www.transportblog.com/archives/000850.html

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Reply #3 - Jan 26^th, 2005 at 9:54am

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not sure about flying, but taxiing can be achieved with 2 engines. flying however hmmm.... well worth a try Tongue

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Reply #4 - Jan 26^th, 2005 at 10:03am

Hagar Offline
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Here's a slideshow presentation about the incident I mentioned. http://www.ph.unimelb.edu.au/~dnj/jl/jl99/sld001.htm

Quote:

In June 1982 a British Airways Boeing 747 lost all four engines and suffered severe damage on encountering volcanic ash over Indonesia. The aircraft descended to 12,000 feet before being able to restart some engines and make an emergency landing in Jakarta.

There's also a book about it.
Quote:

Tootell, Betty. "All Four Engines Have Failed": The True and Triumphant Story of BA 009 and the "Jakarta Incident." London: Andre Deutsch, 1985. 192 pp. Concerns the British Airways B-747 (G-BDXH) volcanic ash encounter which occurred southeast of Jakarta on June 24, 1982.

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Reply #5 - Jan 26^th, 2005 at 11:42am

commoner Offline
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...mmm...Ah yes! Cheesy

BUT they restarted some engines...if they hadn't, THEN it would have flown straight to the scene of the crash don't you think?..commoner

"In theory, there is no difference between theory and practice. But, in practice, there is."

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Reply #6 - Jan 26^th, 2005 at 11:47am

Hagar Offline
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Nobody will ever know. Nobody mentioned loss of control although some systems might not have functioned. Assuming it could glide far enough to reach an airfield or suitable open area I'm sure they could have landed it somehow. If not they would have been forced to ditch in the sea.

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Reply #7 - Jan 26^th, 2005 at 4:18pm

beefhole Offline
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Quote:

This stopped all the engines but it glided for several 100 miles I believe before they were able to restart them.

Are you sure it was hundres of miles? I'm pretty sure the world record is something like 75 set by that A330.

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Reply #8 - Jan 26^th, 2005 at 4:32pm

Hagar Offline
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Quote:

Are you sure it was hundres of miles? I'm pretty sure the world record is something like 75 set by that A330.

No I'm not sure at all. Maybe a slight exaggeration. It was a long time ago & I was working from memory. At least my long-term memory still seems to be OK. Roll Eyes

I found the references after posting that. Wink

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Reply #9 - Jan 27^th, 2005 at 8:26pm

JerryH Offline
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I've taken the original discussion one step further. Using the default B747 in FS2002, I tested the performance with 1, 2 and 3 engines out.

My method was to climb to a cruise altitude of 10,000 ft and maintain 250 KIAS using the AP and AT. Takeoff gross weight was 853,000 lb. The results below show which engines were operating and the N1% for those engines.

Engines 1, 2, 3, 4 . . . . . N1 = 66%
Engines 2, 3, 4 . . . . . . . N1 = 71%
Engines 2, 3 . . . . . . . . . N1 = 78%
Engine 2 only . . . . . . . . N1 = 97%

The one-engine operation gets rather shaky at 97% N1. Even a shallow turn would push the engine too hard, so the altitude would have to drop.

All of this assumes the FS model is absolutely right on, and we all know that's highly unlikely. I also doubt that any of the engine-out cases include the added drag of windmilling engines.

Just thought I'd throw this into the discussion. Maybe someone could do the same thing with the MelJet (or one of the payware 747s) and see how it compares.

Regards,
JerryH

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Reply #10 - Jan 28^th, 2005 at 3:00am

commoner Offline
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..mmm...interesting stuff Jerryh...how come you didn't take that to it's logical conclusion and attempt to land at an airport.....or maybe Craig would like to try it and get the answer to his original question maybe..eh? commoner Wink

"In theory, there is no difference between theory and practice. But, in practice, there is."

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Reply #11 - Jan 28^th, 2005 at 10:02am

AlphaBravo Offline
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thanks i will try it. but at the moment i hav got in to flying the airbus A319 air canada repaint which i downloaded form this site.

Craig

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Reply #12 - Jan 28^th, 2005 at 2:25pm

JerryH Offline
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commoner,

It had occured to me to try a single-engine landing with the big bird. But, at the time, dinner seemed far more important.

JerryH

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Reply #13 - Jan 29^th, 2005 at 3:04am

commoner Offline
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Quote:

commoner,

It had occured to me to try a single-engine landing with the big bird. But, at the time, dinner seemed far more important.

JerryH

lol...YUP...your belly first then the BELLY landing after..commoner Grin

"In theory, there is no difference between theory and practice. But, in practice, there is."

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Reply #14 - Jan 31^st, 2005 at 12:56pm

Straferr Ex Member

There is a company called Boeing in Seattle that has some machines called Link trainers @ 24 mil each. They run programs that are exact profiles of the aircraft they manufacture. The 747 was tested in the Link with all engines dead at 34000 feet and it did a best glide ratio for 385 nautical miles to a safe landing. Finding info on one and two engines will take some time. This is the best I can do today. The only time I worked with that type of machine was with NW airlines when the Cincinnatti crash was attempted on a sim.

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