mhsieh
Posts: 327
Joined: Thu Jul 20, 2000 2:28 pm

Can They Fly On One Outboard Engine?

Fri Mar 07, 2003 4:36 pm

Can the 747 and 340 maintain level flight on one outboard engine only?
What would the Vmc be in order to maintain control with the outboard engine at max thrust?
At what altitude?
 
jhooper
Posts: 5560
Joined: Thu Dec 13, 2001 8:27 pm

RE: Can They Fly On One Outboard Engine?

Fri Mar 07, 2003 5:08 pm

Since no one has answered you yet, I'll do so.

I believe the answer is yes, although the single engine service ceiling is very low. I'm not sure what Vmc would be in this case. Another question for the Skipper!
Last year 1,944 New Yorkers saw something and said something.
 
fritzi
Posts: 2598
Joined: Sat Jun 30, 2001 2:34 am

RE: Can They Fly On One Outboard Engine?

Fri Mar 07, 2003 7:46 pm

Would a fully fueled A343 make it??

Doubtful
 
PIAforME
Posts: 158
Joined: Sat Sep 08, 2001 10:54 pm

RE: Can They Fly On One Outboard Engine?

Fri Mar 07, 2003 10:09 pm

Hi there,

I remember that approx. a year ago there was a thread comprehensively addressing the issues of 4 engine ACs flying on 4-3-2 and one engine and the implications on cruise altitude, sinkrate and climb/descent rate etc etc etc.

try a search

kind regards

Kamran Sarwar
PIAforME
 
411A
Posts: 1788
Joined: Mon Nov 12, 2001 10:34 am

RE: Can They Fly On One Outboard Engine?

Sat Mar 08, 2003 11:33 am

Personally have completed (in the aircraft, not the simulator) a three engine inop (idle thrust) ADF circling approach, descending all the time.
Level flight was not possible, even at lighter training weights.
Speed required with flaps 25 (circling maneuvering flap setting) was 190 knots, rudder boost ON...rudder boost OFF, not possible.
These maneuvers are certainly NOT done any longer in the actual aircraft...with very good reason.
It ain't easy.
 
411A
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Joined: Mon Nov 12, 2001 10:34 am

RE: Can They Fly On One Outboard Engine?

Sat Mar 08, 2003 11:38 am

...forgot to add in the previous, was in the Boeing 707-320B (advanced cowl).
 
Boeing Nut
Posts: 5078
Joined: Fri Feb 23, 2001 2:42 am

RE: Can They Fly On One Outboard Engine?

Sat Mar 08, 2003 11:49 am

I forget what the circumstances were, but I vaguely remember a Pan Am 747 that landed in Japan with only one engine, and it was the outboard.

Regards
I'm not a real aeronautical engineer, I just play one on Airliners.net.
 
EssentialPowr
Posts: 1646
Joined: Wed Sep 06, 2000 10:30 pm

RE: Can They Fly On One Outboard Engine?

Sat Mar 08, 2003 1:39 pm

Can the 747 and 340 maintain level flight on one outboard engine only?

No.....Way.

Jhooper has no idea what he is talking about...particularly if he doesn't specify a weight, and absolutely b/c he doesn't have a performance manual for the 747-xxx/a340-xxx in front of him. A med/heavy 747/A340 would have severe difficulties on 2 engines maintaining 10k msl; anyone that flies either of those a/c can verify but I doubt performance charts are even printed for single engine. A single engine 727 is in a descent, period, and that's a better thrust to weight ratio than a 747/A340 on one.

A bit of advice-Jhooper- a guess may cost you a job, when they come back, b/c it sounds like a guess; which it is...

 
jhooper
Posts: 5560
Joined: Thu Dec 13, 2001 8:27 pm

RE: Can They Fly On One Outboard Engine?

Sat Mar 08, 2003 2:03 pm

I don't have a performance manual in front of me, and I thought I made it pretty clear I was making a guess.

EssentialPowr, just who do you think you are threatening me with my job?
Last year 1,944 New Yorkers saw something and said something.
 
POSITIVE RATE
Posts: 2121
Joined: Sun Sep 16, 2001 11:31 am

RE: Can They Fly On One Outboard Engine?

Sat Mar 08, 2003 4:54 pm

In a 4 engined jet like the 747 or the A340 it cannot maintain height on one engine alone because don't forget one engine= only 1/4 of the toal power supply. But how about a tri-jet say an L1011 or a DC-10? Would one of these be able to manintain level flight on say the centre engine alone??? On a tri-jet one engine= 1/3 of the total power therefore wouldn't it be easier than a 4 engined jet???
 
411A
Posts: 1788
Joined: Mon Nov 12, 2001 10:34 am

RE: Can They Fly On One Outboard Engine?

Sun Mar 09, 2003 12:27 am

Lockheed L1011 (524B powered),

Level flight is possible, at weights below approximately 275,000 pounds with MCT set on the (one) operating engine, provided flaps/slats are retracted, speed is maintained above 210-220 knots, at altitudes no higher (depending on temperature) than 8,000 feet.
 
doug_or
Posts: 3126
Joined: Sat Mar 18, 2000 9:55 am

RE: Can They Fly On One Outboard Engine?

Sun Mar 09, 2003 12:58 am

A single engine 727 is in a descent, period, and that's a better thrust to weight ratio than a 747/A340 on one.

not necesarily. At least in the -100 (even with weak 'ole -7 engines) if you can dump down to a normal post cruise landing weight 110-120ish, and you are smooth on the controls and maintain about 200-210 knots single engined level flight is possible. Though obviously not at cruise altitude.
When in doubt, one B pump off
 
doug_or
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Joined: Sat Mar 18, 2000 9:55 am

RE: Can They Fly On One Outboard Engine?

Sun Mar 09, 2003 1:01 am

and according to performance charts-727-200 with -17 engines:

114.5 lbs 204 kias level flight at 17600 ft with ISA
168.5 will be 2511 at 4100

chart does not specifiy which engines are inop
When in doubt, one B pump off
 
EssentialPowr
Posts: 1646
Joined: Wed Sep 06, 2000 10:30 pm

RE: Can They Fly On One Outboard Engine?

Sun Mar 09, 2003 2:00 pm

From my perf manual for the for -7, -15 and -17 powered 727s...Assume a linear relationship b/t the following points, gross weight(x coord) vs density altitude (y coord), 1 pack, anti ice off, clean a/c, max cont epr:

-7: (110000 lbs, 12000 ft) and (152000 lbs, 0 ft)
-15: (110000 lbs, 16000 ft) and (170000 lbs, 0 ft)
-17: (110000 lbs, 17000 ft) and (177500 lbs, 0 ft)

With MGTOWs rangine approx from 176500 lbs - 220000 lbs, and MLW of around 155000 lbs, a 110000 lb 727 is so very light that its probably the empty a/c plus a few thousand pounds of fuel - not a very likely scenario. A crew couldn't dump/burn fuel fast enough at typical takeoff weights; the a/c is coming down, as I said.

If an -15 powered a/c left DEN (or anywhere) weighing 175000lbs, it's max altitude at 7000 ft is 143000 lbs...A -7 powered a/c would have to weigh 127000 or less to maintain 7000 ft. Even at max dump rates, the point is that the single engine operating envelope is extremely small to the point of being unrealistic for any revenue operation.

Jhooper-this was advice, and it came off harsh...sorry.
I'm trying to encourage you to expand your knowledge base, so you are ready when the returns. There will always be more people willing to fly a/c for a living, part. 121, than there are seats available. Many CFIs are given those exact types of questions at interviews, and blow it. Knowledge is cheap; particularly when compared to experience.

cheers-
 
EssentialPowr
Posts: 1646
Joined: Wed Sep 06, 2000 10:30 pm

RE: Can They Fly On One Outboard Engine?

Sun Mar 09, 2003 2:01 pm

when the hiring returns...
 
doug_or
Posts: 3126
Joined: Sat Mar 18, 2000 9:55 am

RE: Can They Fly On One Outboard Engine?

Sun Mar 09, 2003 2:34 pm

A single engine 727 is in a descent, period

the point is no, its not. if its at MGTOW at a high altitude airport, well then yes it will be.
When in doubt, one B pump off
 
EssentialPowr
Posts: 1646
Joined: Wed Sep 06, 2000 10:30 pm

RE: Can They Fly On One Outboard Engine?

Mon Mar 10, 2003 3:47 am

Doug Or

Yes, it's possible, but as I said - for all practical reasons impossible if the a/c is loaded for any kind of revenue flight. Obviously you haven't understood what I've written about how very light a single engine 727 has to be in order to have enough performance to make a VFR circuit. 114500 is almost the BOW for most 727-200advs. And most fleets don't have the -17s at any rate...I think all of UAls were -15 powered, as were most of NWAs...I think AAL's were -9s.

There are also a critical issues with which engines are lost in terms of hydraulic configuration, icing conditions, etc. which further decrease the odds...but you know all of those, right?

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