gordonsmall
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Aircraft Engine-out Performance.

Wed Jul 09, 2003 5:48 am

Hi All,

I'm looking for pilots opinions on the performance of their respective aircraft when one or more engines have failed/been shut down.

I expect overpowered aircraft like the 757 or MD-11 will be easier to fly in that situation than something like an A340 or 747-100, but would appreciate the opinions of pilots on their own particular aircraft.

Regards,
Gordon.
Statistically, people who have had the most birthdays tend to live the longest.
 
Guest

RE: Aircraft Engine-out Performance.

Wed Jul 09, 2003 6:21 am

Of all the airplanes types I flew so far... 707, 720, 727, 737, 747, DC8, and the Lear 20/30s - The Learjet 23/24 is probably the nastiest little bugger as far as engine-out behavior. Although it has adequate engine-out performance, 2,000 fpm climb with one engine out, but it is difficult to control. Do not consider the Learjet a "centerline thrust" airplane because it has engines on the fuselage... The Learjet 23/24 is also quite unstable aircraft.
xxx
The 707, 747 and DC8s are all pussycats to fly with the loss of an engine at speed V1 on takeoff, or even on 2 engines out (same side) for landing...
xxx
(s) Skipper  Smile
 
gordonsmall
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RE: Aircraft Engine-out Performance.

Wed Jul 09, 2003 6:29 am

Many thanks for the reply skipper.

BTW - what typical climb rate would you get in the 747-200 at MTOW with one engine out?

Gordon.
Statistically, people who have had the most birthdays tend to live the longest.
 
Rick767
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RE: Aircraft Engine-out Performance.

Wed Jul 09, 2003 6:51 am

The 757/767 aircraft are generously overpowered and as such perform well on a single engine climbout or, heaven forbid, a single engine go-around from low level.

The 767-300 is a little less powerful at the very high weights and on hot days - at 30 degrees C and MTOW it will only make 300fpm on one engine so accurate speed control is essential. Takes about 15nm to clean up the aircraft in that situation.
I used to love the smell of Jet-A in the morning...
 
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Francoflier
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RE: Aircraft Engine-out Performance.

Wed Jul 09, 2003 1:04 pm

Gordon,

I don't think the A340 or any 747 would behave badly in the case of an engine failure. Remember, they only lose 25% of the overall power.

I could understand why someone would think that a 4-blower would have a hard time staying airborne with an dead engine when it already seems to be struggling for altitude with all 4 on. As I said, you only lose a quarter of the power, so the other 3 engines do not need all that extra power to maintain required engine-out performance.

However on a twin engine, you would lose 50% of your thrust, meaning both engine need to be plenty powerful to single-handedly lift the plane and its full load of scared passengers up to safety altitude.

This is why twin engine seem so impressive on t/o, they all are overpowered with the 2 engines running, while their 4 engine brothers do not need all that extra power, resulting in non-photogenic t/o's...

How about losing 2 engines on the same side? It is just too improbable, since you'll land as soon as you can when you lose the first one, unless it is a catastrophic failure with parts flying out everywhere and hitting the other engine, in which case you never should have got up from bed that morning...

Could anyone with experience on the A340 or early 4 engine jets help?

Regards.
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
gordonsmall
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RE: Aircraft Engine-out Performance.

Wed Jul 09, 2003 8:05 pm

Hi Francoflier,

Thanks for your reply.

I know the physics of why 4 engine jets climb slower than twins or tri-jets but let's face it the A340-300 with 5C2 engines or the 747-100 with early P&W's could hardly be described as overpowered even with all 4 motors turning.

Obviously these aircraft are more than capable of flying with one engine out, and I think I have even seen footage of a Sabena A340 landing on only two engines, but surely they would be more difficult to fly than say a 747-400 which has a much better power to weight ratio.

My query was not whether they COULD fly with an engine out, rather how DIFFICULT a particular aircraft was to fly in that situation and whether there were any gotcha's to watch out for (such as skipper's observation that the Lear 23/24 is particularly difficult to control despite the engines being fuselage mounted).

Basically I was not comparing twins to 4-holers, rather looking for a balanced comparison and opinion on all aircraft from light twins to 747's and on to (and I'm taking things to an extreme here) the B-52.

I don't expect we'll have many B-52 drivers on the forum but I hope this clarifies my question.

Gordon.
Statistically, people who have had the most birthdays tend to live the longest.
 
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Francoflier
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RE: Aircraft Engine-out Performance.

Mon Jul 14, 2003 11:07 am

Hi Gordon.

Sorry about the unnecessary talk then. Maybe it helped someone else?

I'm sure a new generation 747, or the A343-500 and -600, with the bigger motors behave really better, performance wise, than the early 747, and the first A340... But I wouldn't know, really...

But to answer your original question anyway:
I have flown several types of turboprop so far (no jets yet, but I keep dreaming) and I am somewhat deceived at their performance on 1 engine. Especially the early ones like the f-27. That thing is so heavy and so underpowered you barely feel like you're climbing when you've lost a Dart. I mean it's so lazy at MGW with 2 engines on here in this warm ambient, I'm not even sure it would maintain altitude on 1 engine...
The books and the sim say it should, but I doubt it.

A year and a half ago an engine blew (as in exploded...) on t/o and wouldn't feather. We only had 13 pax (Thank God!!!!) and were barely able to maintain 500ft and 110 Kts around the pattern.

The Atr's and Dash 8 have a much better time at it though.
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
POSITIVE RATE
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RE: Aircraft Engine-out Performance.

Mon Jul 14, 2003 1:35 pm

How about the older generation of twinjets? I'm wondering how these aicraft would do with 1 engine out at MGW since their engines were less powerful tan todays high bypass fans?

F-28(all variants)
DC9-30
MD80
727-100/200
737-200
 
CX Flyboy
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RE: Aircraft Engine-out Performance.

Mon Jul 14, 2003 3:09 pm

The 777 is not too bad an aircraft when it comes to engine out. Even with the gear down, the aircraft manages to climb away unless you are absolutely full, in which case it doesn't climb well at all.

Controllability is excellent however, and on the aircraft we have something called TAC - Thrust Assymetry Compensation. TAC senses when the thrust being produced by the Left and Right engines differs by more than 10% and adds the neccessary rudder trim to couteract it. When an engine failure occurs, TAC will kick in some rudder, however not 100%. This is to allow the pilot to also kick in rudder manually. This enforces in the pilots mind which engine has failed - the Left or Right. (Don't want people shutting the wrong one down - has been done before!) Eventually, the TAC assumes 100% of the rudder control.

When an aircraft loses an engine one of the major dangers is not so much terrain clearance but controllability, and rudder overuse, or lack of, can be a major problem. On the 777 TAC is a godsend with regards to this. Too bad it is always disabled on our simulator checks!!
 
m717
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RE: Aircraft Engine-out Performance.

Mon Jul 14, 2003 11:20 pm

Positive rate,

In response to your question regarding the engine out performance of some older generation twinjets, I have experience with a couple of those.

As far as the 737-200, much depended upon the version of the JT8D engine installed. I have flown them with the -7 (very limited) -9 (average), -15 (decent) and -17 (actually quite good). The -7s or -9s out of PHX on a very hot day left much to be desired, but then I flew the -17s out of many airports in AK, and the performance of those aircraft was fairly impressive.

I also flew MD80s with the JT8D-219s, and they also had more than adequate engine out performance. In fact, at Reno Air, the engine out performance that we were able to demonstrate to the FAA was such that we were able to get approval for a special ILS procedure into RNO that allowed for lower minimums.

 
Guest

RE: Aircraft Engine-out Performance.

Tue Jul 15, 2003 4:18 am

Here's a funny story along these lines (if it's not true it ought to be)...

Several years ago an air force transport was on approach into a USAF SAC base. Approach control advised the transport to breakoff the approach as there was a B-52 that had lost an engine after takeoff and was making an emergency return. Then someone came up on the frequency and said, "Ah, the dreaded 7-engine approach".  Big thumbs up
 
jhooper
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RE: Aircraft Engine-out Performance.

Tue Jul 15, 2003 4:33 am

Just to add to the discussion, if you lose one engine on a twin, you lose way more than 50% performance. And if you lose an engine on a 4-engine plane, you lost way more than 25% performance.
Last year 1,944 New Yorkers saw something and said something.
 
goboeing
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RE: Aircraft Engine-out Performance.

Tue Jul 15, 2003 4:41 am

Jhooper,
Could you explain that? Is it because you'd lose some performance in the failed engine creating more drag, even if it's windmilling/feathered, plus the rudder input adds more drag?

Nick
 
Yikes!
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RE: Aircraft Engine-out Performance.

Tue Jul 15, 2003 8:45 am

Jhooper is right, kind of. A light twin engine plane like the old Seneca 1 lost 92% of its ability to climb with an engine failed. Theoretically, it lost 50% of its power, but its the aircraft's ability to perform that Jhooper was referring to.

I believe!

Numbers for twin jets would be different of course, but I think that was the road he was going down with his comment.

Please correct me if I've got it balled up.
 
aaron atp
Posts: 517
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RE: Aircraft Engine-out Performance.

Tue Jul 15, 2003 9:34 am

cx flyboy mentioned the TAC system on the supertube, but it doesn't take a FBW aircraft to have such amenities...

here's the rudder bias system on the Hawker



this is so ingenious I won't bother to explain it...


aaron
 
ConcordeBoy
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RE: Aircraft Engine-out Performance.

Tue Jul 15, 2003 9:35 am

How about losing 2 engines on the same side? It is just too improbable, since you'll land as soon as you can when you lose the first one, unless it is a catastrophic failure with parts flying out everywhere and hitting the other engine, in which case you never should have got up from bed that morning...

Hmm, tell that to the pax of AF4590  Insane  Sad
Faire du ciel le plus bel endroit de la terre c'est impossible sans Concorde!
 
aaron atp
Posts: 517
Joined: Sun Mar 19, 2000 1:17 pm

Climb Performance

Tue Jul 15, 2003 9:51 am

another way of saying it... (for twins)

You lose 50 percent of your rated thrust, but you lose a lot more than 50% of your excess thrust (excess equals what the jet/prop is actually producing minus what is required for level flight, aka drag)

Remembering of course, that excess thrust is what allows your aircraft to climb... If you are doing the math of it, and your excess thrust is negative, you'll be doing a drift-down to your SE absolute ceiling (when excess thrust = 0 ---> which means thrust equals drag).

aaron
 
CX Flyboy
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Joined: Sun Dec 26, 1999 6:10 pm

RE: Aircraft Engine-out Performance.

Tue Jul 15, 2003 10:15 am

Aaron_atp,

That's a very interesting diagram and indeed a very clever yet simple way of aiding the pilot during an engine failure or thrust anomaly.
 
gigneil
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Joined: Fri Nov 08, 2002 10:25 am

RE: Aircraft Engine-out Performance.

Tue Jul 15, 2003 11:09 am

I'm not an expert on such matters... but the A340-300 (non X), 747-100, and 747-400 should all have similar power to weight ratios.

The 744 is much heavier than the 741, just like the A340-300X is a fair bit heavier than the A340-300.

As such, it should be a relational increase - not a huge differential.

N
 
Mr.BA
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RE: Aircraft Engine-out Performance.

Tue Jul 15, 2003 4:51 pm

Just a short note the B744 is not a lot heavier than the B741. I believe the B744 is just a bit heavier. The B744 has different wing designs compared to the B741/2/3... the B744 engines indeed produce more thrust too but let's not forget the B744 has a higher MTOW.

Cheers!  Smile
Boeing747 万岁!
 
POSITIVE RATE
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RE: Aircraft Engine-out Performance.

Tue Jul 15, 2003 11:59 pm

I've heard the IL-62 is a real dog with 1 engine inop at MGW.
 
gigneil
Posts: 14133
Joined: Fri Nov 08, 2002 10:25 am

RE: Aircraft Engine-out Performance.

Wed Jul 16, 2003 3:37 am

By heavier, I was definitely referring to MTOW, not empty weight.

Sorry.

N
 
JohnM
Posts: 379
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RE: Aircraft Engine-out Performance.

Wed Jul 16, 2003 11:19 am

Turbine twin helicopters- no yaw, just loose 50% of available torque. A fairly light UH-60 for example, not real high PA, takes off just fine on one engine. At cruise, once again not real heavy, hard to tell anything has happened at all when one quits!
 
411A
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RE: Aircraft Engine-out Performance.

Wed Jul 16, 2003 5:02 pm

An example of older 4 engine jet airliner climb performance with one outboard engine failed would be...

B707-327B (advanced), takeoff weight 336,000 pounds, 40C, near sea level airfield, 12,000 foot runway

Engine failure at just before V1, ground roll 11,000 feet, climb at V2, 300 feet/min.

Not particularly spiffy.

Or another scenario.
B707-331 (JT4A) engines, max weight, near sea level airport, 23C, 12,000 foot runway, ALL engines operating,

Ground roll 11,000 feet, climb at V2+10, 400 feet/min.

Not all that good either.

TurboFAN powered aircraft much better for airfield performance.

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