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PolymerPlane
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Tri-jets Single Engine Capability

Thu Jun 08, 2006 1:03 am

I just thought about this when discussing ETOPS in civil aviation forum.

How capable is a single engine in a trijet. Can it fly the plane to the nearest diversion airport or does it have to make an emergency ditch with one engine?

My point is since ETOPS is limited to twin, to reduce the probability of dual engine failure to a very minimum, a trijet, if it is not capable of flying with one engine, should it not be also required to observe ETOPS, since a dual engine failure will have the same result as twin?

I know that a quad can continue to nearest diversion airport with 2 engines left, thus having extra capabilities that twin does not. That is why I am really curious about trijet.

Cheers,
PP
 
SP90
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 3:40 am

Is it possible to turn off the middle engine in trijets and just cruise on the remaining 2?
 
SlamClick
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 3:48 am

The last remaining engine can always get you to the scene of the crash.

I flew the BAe-146 simulator with two out on the same side a number of times. Served as gearlifter to a check airman getting his final checkride in one - got down to one engine and it was a 200-300 foot per minute descent. He managed to get it to the runway for a fair landing.

I believe that a 727 down to one engine will also be hard-pressed to maintain any altitude with normal loads. Dump fuel from all tanks is my guess.
 
ANother
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 6:18 am

Quoting SP90 (Reply 1):
Is it possible to turn off the middle engine in trijets and just cruise on the remaining 2?

IIRC Wardair used to do exactly that with their B727s between Canada and Europe. (Probably in the 60s or early 70s). Although slower they extended the range enough to do it non-stop.

Not 100% sure of this, could be an urban legend.
 
dw747400
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 7:38 am

Quoting ANother (Reply 3):
Not 100% sure of this, could be an urban legend.

I'm pretty sure it is a legend. I'd heard that something similiar was investigated with the DC-10, but the engineers working on it decided the windmilling engine wouldn't be properly lubricated and could be damaged.
 
SlamClick
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 8:40 am

I'll look around for my 727 performance stuff but I am almost positive that specific range, that is 'nautical air miles per thousand pounds of fuel' would suffer doing that. It would be less economical, not more. Give me a day or so to find my charts unless someone else has numbers handy.

I'm betting urban legend.
 
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ptrjong
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 8:49 am

Quoting SlamClick (Reply 5):
specific range, that is 'nautical air miles per thousand pounds of fuel' would suffer

Would endurance improve though? Meaningless for a transport flight, but I believe RAF Nimrods often fly or flew on only two engines while on patrol.

Peter
 
SlamClick
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 8:52 am

Quoting Ptrjong (Reply 6):
Would endurance improve though?

Not sure. Of course since airliners never want to 'loiter' endurance is not a big concept for them as it is for patrol/bomber aircraft.

Oddly enough I have ridden over a thousand miles on the jumpseat of a 727 after a precautionary shutdown of number 2 and never once thought to pay attention to fuel consumption.
 
2H4
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 8:54 am



I once spoke with an L-1011 pilot who said cruising with one shut down would result in increased fuel flow.




2H4


 
PolymerPlane
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 10:16 am

So basically on 1 engine you cannot determine the faith of your aircraft if you are like 5 hours off the nearest landing field?

Don't you guys think that tri-jets should observe ETOPS rule as well?

Cheers,
PP
 
3DPlanes
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 11:08 am

Quoting PolymerPlane (Reply 9):
Don't you guys think that tri-jets should observe ETOPS rule as well?

I think you might be misunderstanding the rule... If a twin loses an engine, they're down to one and would be diverting to the nearest suitable field.

If a tri-jet loses one, they would likely also be diverting to the nearest field (especially if over water), but would still have two engines left. The plane is still plenty flyable.

Quoting SlamClick (Reply 7):
I have ridden over a thousand miles on the jumpseat of a 727 after a precautionary shutdown of number 2

So, flying on two is vastly different than flying on one, and even if for some odd reason you did get down to only one, you're still better off than a twin that loses a second engine... 300 feet per minute coming down from FL350 is gonna take more than an hour and a half.

-3DPlanes
 
artsyman
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 12:00 pm

I believe a Continental DC10 on its way to BRU got down to one engine out of EWR a few years back. Don't recall many of the details, but think the remaining engine was pretty cooked by the time it landed
 
arluna
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 12:33 pm

Hello all,

Since this is my first posting please be gentle with me if I am wrong but how about the Eastern L-1011 out of Miami that lost power on all three engines after departure due to the wrong oil plugs being installed after maintenance and losing the oil out of all three engines. I think this happened sometime in the '80s.

IIRC he managed to get no. 2 restarted and made it back to Miami on one and landed safely.

Jerry
 
DC-10Tech
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 1:09 pm

I know the last time I saw the drift down chart on a DC-10-10, with two engines out, the optimum altitude (for an empty aircraft) was a negative number.  Sad

If you're down to one engine on a tri-jet, you are basically a severely underpowered glider. That last engine will help you maintain flyable airspeed, but you pretty much have to be decending the whole time.
 
PolymerPlane
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 1:42 pm

Quoting 3DPlanes (Reply 10):
I think you might be misunderstanding the rule... If a twin loses an engine, they're down to one and would be diverting to the nearest suitable field.

If a tri-jet loses one, they would likely also be diverting to the nearest field (especially if over water), but would still have two engines left. The plane is still plenty flyable.

I understand that when a twin loses engine, they are down to one and have to divert. But, twin has a very capable engine. They can fly with one engine, even make a go around and climb with it.

What I am trying to say is that when losing two engine, both twin and tri-jet cannot really determine their own destiny.

Just like this quote:

Quoting DC-10Tech (Reply 13):
I know the last time I saw the drift down chart on a DC-10-10, with two engines out, the optimum altitude (for an empty aircraft) was a negative number.

If you're down to one engine on a tri-jet, you are basically a severely underpowered glider. That last engine will help you maintain flyable airspeed, but you pretty much have to be descending the whole time.

If the main purpose of ETOPS is getting a diversion within a reasonable limit such that the second engine failure does not happen, because with second engine failure the result will be catastrophic, then IMO both trijet and twin should observe the ETOPS rule.

Cheers,
PP
 
DC-10Tech
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 2:17 pm

Quoting PolymerPlane (Reply 14):
If the main purpose of ETOPS is getting a diversion within a reasonable limit such that the second engine failure does not happen, because with second engine failure the result will be catastrophic, then IMO both trijet and twin should observe the ETOPS rule.

Well, apparently the people that right the regulations don't agree with you. You are comparing operating a twin with one engine out to operating a trijet with two out. Why don't you compare a twin with two out instead? The whole argument is retarded.

If a twin loses one engine, it need to find a place to land within the ETOPS time constraints. If a tri-jet loses an engine, he's still got two left and can fly just fine.
 
PolymerPlane
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 2:46 pm

Quoting DC-10Tech (Reply 15):
Well, apparently the people that right the regulations don't agree with you. You are comparing operating a twin with one engine out to operating a trijet with two out. Why don't you compare a twin with two out instead? The whole argument is retarded.

Did you even read my argument? I am comparing two engine out for both twin and trijet. I am trying to say for two engine out, both trijet and twin do not have the ability to find the suitable diversion point above a certain range. You said it yourself that for example DC 10-10 cannot really climb or even stay at a constant altitude with only one engine.

See this is what I said (trying to make it easy for you to read that I actually compared a twin and a trijet losing two engines):

Quoting PolymerPlane (Reply 14):
What I am trying to say is that when losing two engine, both twin and tri-jet cannot really determine their own destiny.

I know that the regulators do not agree with me, but if I cannot express my view, why are we even on a discussion forum?

Quoting DC-10Tech (Reply 15):
If a twin loses one engine, it need to find a place to land within the ETOPS time constraints. If a tri-jet loses an engine, he's still got two left and can fly just fine.

If a twin loses one engine it still can fly just fine to its destination. It has the capability to do so just like a trijet with one engine out. It is the ETOPS regulation that forces a twin to divert to the nearest field to reduce the overall probability of losing two engine, which could be catastrophic.

Pay attention carefully for my next argument because this is my main argument and I am comparing both a twin and a trijet losing two engine, which is not retarded. Losing two engines for a trijet and a twin has the same effect of not being able to stay afloat to find the nearest diversion point. Granted that a trijet still have one power plant and can "glide" with losing 100-200fpm, still, above a certain distance a trijet will not be able to reach the nearest diversion point with only one engine.

I did not make a case against quad, since quad with two engine out still can hold an altitude to find a nearest diversion point.

Cheers,
PP
 
EssentialPowr
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 2:57 pm

Ok,ok...I got out my book...
Alt. Capability for the following conditions:

A 727, 2 engines inop, Std OAT, 1 pack off, Anti ice off, Gear/flaps up, Max cont EPR, 1 eng climb IAS:

Alt vs Gross weight plot, linear curve

JT8D-15
at 170000 lbs, 1500 MSL; at 110000 lbs, 16700' MSL

for the -7

at 14000, 2400 MSL; at 110000 lbs, 11900 MSL

for the -17

at 180000, 250 (3 digits) MSL; at 110000 lbs, 17800 MSL.

In other words, you have a shot out of a sea level airport in the winter...otherwise, in the case of the 727, the single engine just arrests the descent rate. I've got a 2 engine inop go around table here too, but it aint happening unless it's a cold day in Tampa.

cheers-
 
SlamClick
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 10:49 pm

Quoting PolymerPlane (Reply 16):
It is the ETOPS regulation that forces a twin to divert to the nearest field to reduce the overall probability of losing two engine,

This is not a correct statement. ETOPS is a whole different sphere of operations from normal twinjet flying. The huge majority of twinjet flying is not ETOPS.

FAR 121.565 (a) Except as provided in paragraph (b) of this section, whenever an engine of an airplane fails or whenever the rotation of an engine is stopped to prevent possible damage, the pilot in command shall land the airplane at the nearest suitable airport in point of time at which a safe landing can be made.


Paragraph (b) gives exemption to this rule in the case that "not more than one engine of an airplane that has three or more engines fails..."

This has nothing to do with ETOPS.

Fact is, a twin jet airliner that has already met takeoff performance criteria does not have much difficulty maintaining safe altitude when an engine is lost at cruise. The landing is, in effect, precautionary, not a dire emergency.
 
PolymerPlane
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 10:59 pm

Quoting SlamClick (Reply 18):
This has nothing to do with ETOPS.

Fact is, a twin jet airliner that has already met takeoff performance criteria does not have much difficulty maintaining safe altitude when an engine is lost at cruise. The landing is, in effect, precautionary, not a dire emergency.

Thank you for the correction, but that is still beside the point. Maybe the discussion should not be within ETOPS framework, but more accurately that whether a trijet should divert to a nearest suitable field in case of one engine shutdown.

Cheers,
PP
 
DH106
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 11:22 pm

Quoting Arluna (Reply 12):
Since this is my first posting please be gentle with me if I am wrong but how about the Eastern L-1011 out of Miami that lost power on all three engines after departure due to the wrong oil plugs being installed after maintenance and losing the oil out of all three engines. I think this happened sometime in the '80s.

IIRC he managed to get no. 2 restarted and made it back to Miami on one and landed safely

I think he just used no. 2 to "strech the glide" a little, since it was very low on oil and was being treated gently. He wouldn't have been able to maintain level flight on just the one, but in this case it certainly made the difference between a certain ditching and just being able to scrape back into Miami.

I understand that after the landing the engine siezed when they attempted to taxi off the runway to the apron !  Wow! They don't come much closer than that!
 
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ptrjong
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 11:24 pm

Quoting DC-10Tech (Reply 13):
If you're down to one engine on a tri-jet, you are basically a severely underpowered glider. That last engine will help you maintain flyable airspeed, but you pretty much have to be decending the whole time.

If the single working engine was #2, would the absence of asymmetric thrust make a difference in your chances to make it somewhere?

Especially in a DC-10 or similar, where the asymmetric thrust would be rather worse than in a 727 or similar with only #1 or #3 working.
 
SlamClick
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 11:45 pm

Quoting PolymerPlane (Reply 19):
but more accurately that whether a trijet should divert to a nearest suitable field in case of one engine shutdown.

For sure a discussion of 3 and 4-engine airplanes should not be in an ETOPS framework since ETOPS means Extended Two-engine Operations. Everything about ETOPS is non-applicable to three and four holers.

The remainder of the regulation (121.565) that I cited says that an airplane having three or more engines that loses only one of those engines may continue to its destination if that course of action is 'as safe as' landing at the nearest suitable airport.

At first glance you might say well how could it be as safe as... but the reg is written to cover all conceivable situations. So let's say we've departed SFO for ORD in a DC-10. Twenty five minutes later we shell an engine. Now the nearest suitable airport is hot-and-high Reno.

Landing an overweight DC-10 on two engines on a hot day at RNO might not be our first choice. So we press on. Next really suitable airport, maybe SLC. Also hot and high. On our northerly routing next comes Rock Springs Wyoming. Not with me aboard! Denver? Still hot and high. Now the continent begins to slope away toward the Missouri and Mississippi River valleys and toward the great lakes. Well, we are downhill to Chicago now. Press on.

Unless you determined that it would be worthwhile to get recleared back into busy, delay-prone SFO, pressing on to Chicago might be a good choice. The decision of course would be based on all information available to you. If the engine just flamed out and will not restart that is one case, if it failed explosively you might want to be on the ground sooner.
 
artsyman
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RE: Tri-jets Single Engine Capability

Thu Jun 08, 2006 11:53 pm

 
EssentialPowr
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RE: Tri-jets Single Engine Capability

Fri Jun 09, 2006 3:19 am

Quoting Ptrjong (Reply 21):
If the single working engine was #2, would the absence of asymmetric thrust make a difference in your chances to make it somewhere?

The data I provided don't distinguish which engine is running; that therefore leads me to believe it to be insignificant on the 727...same with system rudundancy, as that is your last concern when flying a 727 w/ 1 engine.
 
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Starlionblue
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RE: Tri-jets Single Engine Capability

Fri Jun 09, 2006 3:53 am

Quoting EssentialPowr (Reply 24):
The data I provided don't distinguish which engine is running; that therefore leads me to believe it to be insignificant on the 727...same with system rudundancy, as that is your last concern when flying a 727 w/ 1 engine.

The engines on the 727 are so close to centerline there won't be much drag resulting from asymmetric thrust. Thus also the small fin compared to, say the 757.

On the DC-10 the wing engines are a mite further out.
 
EssentialPowr
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RE: Tri-jets Single Engine Capability

Fri Jun 09, 2006 4:02 am

Quoting Starlionblue (Reply 25):
The engines on the 727 are so close to centerline there won't be much drag resulting from asymmetric thrust. Thus also the small fin compared to, say the 757.

On the DC-10 the wing engines are a mite further out.

Yeah...I think I got the idea of the moment due to wing mounted engines which is why I re indicated that I provided data on the 727.

Quoting EssentialPowr (Reply 24):
The data I provided don't distinguish which engine is running; that therefore leads me to believe it to be insignificant on the 727

Whether the rudder input req'd, if flying single engine on the #1 engine of a DC10, is significant can only be verified by looking at the 2 engine inop tables for the -10. Do you have them?
 
PolymerPlane
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RE: Tri-jets Single Engine Capability

Fri Jun 09, 2006 4:07 am

Quoting SlamClick (Reply 22):
At first glance you might say well how could it be as safe as... but the reg is written to cover all conceivable situations. So let's say we've departed SFO for ORD in a DC-10. Twenty five minutes later we shell an engine. Now the nearest suitable airport is hot-and-high Reno.

Does this situation also apply to twin? I mean for twin it should be the nearest suitable airfield, but if it is hot and high and the aircraft is not capable to make a safe land, including performing a go around, it would not be a suitable airfield right?

I know a quad and trijet should not be discussed in ETOPS framework. Regardless of the name of the rule, I am just thinking, when losing 2 engines, the faith of a twin and a trijet is almost the same, in regard to the ability of finding a suitable field to make a safe land. Since, when losing two engines, basically both type of aircraft is a glider, thus, not being able to maintain a constant cruise altitude to find nearest field.

So, let say you are in the middle of nowhere in pacific. When losing two engines, both a twin and a trijet will have to ditch if there is no close airfield to glide to.

However, to reduce the probabilty of this scenario, twin has ETOPS rule, which includes preventing a systematic error by having different mechanics working on the different engine and an order to divert as soon as there is one engine failure. A trijet does not have this kind of regulation, which means a dual engine failure is more likely than an ETOPS twin.

Shouldn't there be a rule just like ETOPS for trijet as well in this scenario?

Cheers,
PP
 
twal1011727
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RE: Tri-jets Single Engine Capability

Fri Jun 09, 2006 4:17 am

Quoting SlamClick (Reply 22):
At first glance you might say well how could it be as safe as... but the reg is written to cover all conceivable situations. So let's say we've departed SFO for ORD in a DC-10.

My dad flew the L10 for TWA. On one flight from SLC to JFK, the accessory gear drive on the #2 engine sheared - gradually shutting the engine down. He decided to divert to DEN (nice cold winter day) than dump fuel or do an overweight landing. If this was a 2 holer than he would have turned around and returned to SLC.

KD MLB
 
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Starlionblue
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RE: Tri-jets Single Engine Capability

Fri Jun 09, 2006 9:14 am

Quoting PolymerPlane (Reply 27):
Does this situation also apply to twin? I mean for twin it should be the nearest suitable airfield, but if it is hot and high and the aircraft is not capable to make a safe land, including performing a go around, it would not be a suitable airfield right?

As you say, the rule says "nearest suitable", not "nearest". The rule is not a suicide pact. Besides, the Captain is tasked with operating the aircraft in a safe manner, meaning he does have some latitude in order to be as safe as possible.

Quoting PolymerPlane (Reply 27):

I know a quad and trijet should not be discussed in ETOPS framework. Regardless of the name of the rule, I am just thinking, when losing 2 engines, the faith of a twin and a trijet is almost the same, in regard to the ability of finding a suitable field to make a safe land. Since, when losing two engines, basically both type of aircraft is a glider, thus, not being able to maintain a constant cruise altitude to find nearest field. So, let say you are in the middle of nowhere in pacific. When losing two engines, both a twin and a trijet will have to ditch if there is no close airfield to glide to.

The "fate" may be the same, but the timescales are widely different. Even on one engine, the trijet can probably go a very long way. The twin is pretty much limited to a glide ratio of 20:1, or about 200km if at 33000ft. But yes, in the middle of the pacific there's not much you can do.
 
DC-10Tech
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RE: Tri-jets Single Engine Capability

Fri Jun 09, 2006 2:00 pm

Quoting PolymerPlane (Reply 19):
Thank you for the correction, but that is still beside the point. Maybe the discussion should not be within ETOPS framework, but more accurately that whether a trijet should divert to a nearest suitable field in case of one engine shutdown.

Now that is a better way to word the question. Yes, with one engine out the crew should land at the nearest suitable airport. Now, 'nearest suitable' means different things to different pilots. I myself have crewed an MD-11 where we lost #3 engine and continued flying 3.5 hours from Bogota to Miami because it was more suitable to change the engine in Miami where we had one vs trying to do it in Colombia where we had nothing.
 
MYT332
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RE: Tri-jets Single Engine Capability

Fri Jun 09, 2006 10:00 pm

Quoting SlamClick (Reply 22):
Landing an overweight DC-10 on two engines on a hot day at RNO might not be our first choice. So we press on.

So that analogy in theory is identical to what my countrymen did ex LAX? They thought the best thing to do was go to MAN right?
 
DH106
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RE: Tri-jets Single Engine Capability

Fri Jun 09, 2006 10:16 pm

Quoting Myt332 (Reply 31):
So that analogy in theory is identical to what my countrymen did ex LAX? They thought the best thing to do was go to MAN right?

I doubt it's any pilot's 'first choice' to go long haul over an ocean without a full compliment of engines. It's a little different to continuing across contintal U.S.
I really can't think what got into the pilot's heads, - lose another engine and they'd be in a more serious position than say an ETOPS 2 holer with one engine out as twins have a higher power to weight ratio. Were they lightly loaded - did that influence their decision? Did they alter their route at all - similar to the way ETOPS routings hug the land a little ?
 
Max Q
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RE: Tri-jets Single Engine Capability

Sat Jun 10, 2006 1:30 pm

We used to do a two engine inoperative drill in the simulator on recurrent checks in the 727-200.

The scenario was a two engine (one engine inoperative approach) followed by a go around (missed approach) with a consequent further engine failure.

This was a very critical situation that demanded immediate action.

To survive you needed to get clean ASAP (Gear and flaps up) you had to lower the nose quite rapidly, but not too quick while advancing power to Maximum continous on the remaining engine and telling the Engineer to dump fuel immediately to the standpipes (3500 pounds per tank)

The number I remember was around 200 Knots, at which speed she would SLOWLY fly away on one and you would return for a flaps 5 landing.

1-200 feet per minute was about all you could get.The challenge was to get that speed quickly witout hitting the ground, too much of a pitch change would do that, but too little had you descending into the ground anyway on the back side of the power curve.

All theoretically possible at sea level in moderate temperatures, otherwise.....
 
411A
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RE: Tri-jets Single Engine Capability

Sun Jun 11, 2006 1:02 am

Hmmm, so far no one has seemed to provide any actual numbers for a three engine airplane (to answer the original question) so here are a few, from the L1011.

In both -22B and 524B powered models, 2 engine cruise results in (approximately) 500kg more fuel burn, per hour, and a reduction of 40 knots in cruise TAS.

-22B powered models, at 400,000 pounds cruise weight, std temperature.

2 engine cruise, FL190
1 engine cruise, 8000 feet

-524B402 powered models, 400,000 pound cruise weight, std temperature,

2 engine cruise, FL240
1 engine cruise, 14,000 feet


IF two engines fail just after takeoff, continued flight is possible, provided...

-22B powered models, the TOW is less than 360,000 pounds (std temperature)

-524B402 powered models, the TOW is less than 390,000 pounds (std temperature

In the above two cases, flaps/slats are IMMEDIATELY retracted to 4 degrees until 180 knots is reached, then fully retracted, and the aircraft accelerated to 210KIAS, before climb is commenced.
 
EssentialPowr
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Joined: Wed Sep 06, 2000 10:30 pm

RE: Tri-jets Single Engine Capability

Sun Jun 11, 2006 3:10 am

Quoting 411A (Reply 34):
Hmmm, so far no one has seemed to provide any actual numbers for a three engine airplane (to answer the original question) so here are a few, from the L1011.

Sir-I provided these for a -7,-15 and -17 powered 727...

[quote=EssentialPowr,reply=17]Ok,ok...I got out my book...
Alt. Capability for the following conditions:

A 727, 2 engines inop, Std OAT, 1 pack off, Anti ice off, Gear/flaps up, Max cont EPR, 1 eng climb IAS:

Alt vs Gross weight plot, linear curve

JT8D-15
at 170000 lbs, 1500 MSL; at 110000 lbs, 16700' MSL

for the -7

at 14000, 2400 MSL; at 110000 lbs, 11900 MSL

for the -17

at 180000, 250 (3 digits) MSL; at 110000 lbs, 17800 MSL.

In other words, you have a shot out of a sea level airport in the winter...otherwise, in the case of the 727, the single engine just arrests the descent rate. I've got a 2 engine inop go around table here too, but it aint happening unless it's a cold day in Tampa.
 
David L
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RE: Tri-jets Single Engine Capability

Sun Jun 11, 2006 3:50 am

Quoting DH106 (Reply 32):
I doubt it's any pilot's 'first choice' to go long haul over an ocean without a full compliment of engines.

I guess having a full compliment of engines would be the first choice but... under the circumstances..?

Quoting DH106 (Reply 32):
I really can't think what got into the pilot's heads,

Training and experience, perhaps?

You might want to take a look at the AAIB report, linked to here:
747-400 LAX-LHR 3 Engine Flight Report Now Out. (by JulianUK Jun 8 2006 in Tech Ops)

No mention of any recklessness in continuing on three engines, just a recommendation that the engine-out fuel management procedures be improved. Heaven help us if the AAIB and BA pilots are incompetent.
 
474218
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RE: Tri-jets Single Engine Capability

Sun Jun 11, 2006 4:49 am

Quoting 411A (Reply 34):
In the above two cases, flaps/slats are IMMEDIATELY retracted to 4 degrees until 180 knots is reached, then fully retracted, and the aircraft accelerated to 210KIAS, before climb is commenced.

411A, I agree with everything you said except with retracting the flap/slats to 4 degree. You can only retract the flaps to four degrees. The slats are either full up or full down. They are controlled by the flap handle and the flap/slat programmer (found in the cabin floor above the Mid Electrical Service Center). On flap extension, when the handle reaches the 4 degree detent the programmer extends the slats. On flap retraction the movement of the flap handle out of the 4 degree detent (towards 0) allows the programmer to retract the flaps fully.

So if you retract the flat to 4 degree the slats are still fully extended.
 
411A
Posts: 1788
Joined: Mon Nov 12, 2001 10:34 am

RE: Tri-jets Single Engine Capability

Sun Jun 11, 2006 7:56 am

Nearly correct, 474218.

In reality, it is the flap HANDLE passing the 3 degree position, that directs the slats to extend or retract.
Switches in the console, and actuated by flap handle movement, control the signals sent to the flap/slat programmer.

Likewise, when selecting landing flaps 33, the DLC action begins when the flap HANDLE passes the 30 degree position.

That little 'ole flap handle is one important item.

Going further, a few eagle-eyed folks might say...why do you retract the flaps/slats at such a low airspeed, when two engines fail just after takeoff?

The simple answer is...the airplane will not climb on one engine, if slats/flaps are extended, at any weight.
Therefore, flap/slat retraction is required at lower than normal speeds, and as a result, turns are to be avoided, if at all possible.

[Edited 2006-06-11 01:01:49]

[Edited 2006-06-11 01:03:38]
 
474218
Posts: 4510
Joined: Mon Oct 10, 2005 12:27 pm

RE: Tri-jets Single Engine Capability

Sun Jun 11, 2006 11:57 am

Quoting 411A (Reply 38):
Nearly correct, 474218.

In reality, it is the flap HANDLE passing the 3 degree position, that directs the slats to extend or retract.

Close but the actual degrees where the slats extend/retract is 3.3 to 3.8 degrees. But as I said: The slats do not retract until the handle has been moved past the 4 degree detent toward 0.

Quoting 411A (Reply 38):
Likewise, when selecting landing flaps 33, the DLC action begins when the flap HANDLE passes the 30 degree position.

DLC is activated at 28 degrees.

Quoting 411A (Reply 38):
Switches in the console, and actuated by flap handle movement, control the signals sent to the flap/slat programmer.

The flap quadrant switches are mentoring switches only and do not effect actuation. All L-1011 flight controls (including the flaps and slats) are called Fail Superior, meaning they do not require electrical power to make them function. Electrical power is used to shut them off. So if electrical power fails you can still fly the L-1011.
 
411A
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RE: Tri-jets Single Engine Capability

Sun Jun 11, 2006 2:15 pm

>>DLC is activated at 28 degrees.<<

Not on the models that I fly.

>>The flap quadrant switches are mentoring switches only and do not effect actuation. All L-1011 flight controls (including the flaps and slats) are called Fail Superior, meaning they do not require electrical power to make them function. Electrical power is used to shut them off. So if electrical power fails you can still fly the L-1011<<

I think the term you need is fail OPERATIONAL.
No mention in any L1011 book that I have ever seen has mentioned anything about 'fail superior.'

And, I have flown every model.
 
TAM1079
Posts: 88
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RE: Tri-jets Single Engine Capability

Sat Jul 01, 2006 8:37 am

Semantics. 411, you really are a arrogant prick. Quit trying to one up everyone. For Petes sake.
 
411A
Posts: 1788
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RE: Tri-jets Single Engine Capability

Sat Jul 01, 2006 3:11 pm

Not an arrogant prick, TAM1079, as you so quaintly put it...

Having flown the L10 in Command for 26 years, I sure as hell know more about it than you.
Clearly you don't know sh*t from shineola.
Why am I not surprised?

[Edited 2006-07-01 08:36:52]
 
n8076u
Posts: 419
Joined: Mon Jun 19, 2006 10:52 am

RE: Tri-jets Single Engine Capability

Sat Jul 01, 2006 4:45 pm

Not to get off the subject, but is this "DLC" on the L1011 the system where the spoilers control glide slope descent?

Quoting 411A (Reply 40):
I think the term you need is fail OPERATIONAL.

I take it "fail operational" is the term that Lockheed uses in their manuals?

Quoting 411A (Reply 42):
Not an arrogant prick...Having flown the L10 in Command for 26 years...

If I had to guess, I'd say "411A" isn't trying to be arrogant, but rather is very proud of the L1011, and just wants any information posted regarding "his baby" to be as accurate as possible, at least that's how it seems to me. After all, you'd expect someone would have a certain amount of passion and affection for an aircraft after 26 years.  twocents 

Chris
 
411A
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RE: Tri-jets Single Engine Capability

Sun Jul 02, 2006 12:08 am

Indeed Chris, the DLC (direct lift control) on the Lockheed L1011 is used precisely for the purpose you indicated...it helps to maintain a constant aircraft deck angle, during descent on the ILS glidepath.

After landing flaps are selected, certain spoiler panels extended to a 'null' position, and from that null position, either extend further or retract, depending on the descent rate selected to maintain correct height on the glidepath.

If you push forward on the pole, the spoilers move toward extend (within certain limits), whereas it you pull back on the pole, the spoilers move toward retract

If a go-around is required, moving any two throttles toward the go-around thrust position will deactivate DLC and stow the spoiler panels promptly.

A superbly designed system that is very reliable.
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Tri-jets Single Engine Capability

Sun Jul 02, 2006 12:36 am




Quoting 411A (Reply 44):
A superbly designed system that is very reliable.

Why, in your opinion, do you suppose other aircraft manufacturers have not followed suit, and utilized such a system on modern aircraft?




2H4


 
474218
Posts: 4510
Joined: Mon Oct 10, 2005 12:27 pm

RE: Tri-jets Single Engine Capability

Sun Jul 02, 2006 1:58 am

Quoting 2H4 (Reply 45):
Why, in your opinion, do you suppose other aircraft manufacturers have not followed suit, and utilized such a system on modern aircraft?

DLC is standard on the C-17 and was optional on the DC-10.
 
411A
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Joined: Mon Nov 12, 2001 10:34 am

RE: Tri-jets Single Engine Capability

Sun Jul 02, 2006 12:21 pm

Because, 2H4, others (with some exceptions) were not smart enough to realise the benefits.

Lockheed...the BEST there is, positively without exception.
Others may well disagree of course, but until you have actually FLOWN the TriStar, you would have no idea.

It truly is one remarkable jet transport airplane.
Bar none.
 
PolymerPlane
Topic Author
Posts: 832
Joined: Thu May 11, 2006 1:12 am

RE: Tri-jets Single Engine Capability

Sun Jul 02, 2006 12:39 pm

Quoting 411A (Reply 47):
Because, 2H4, others (with some exceptions) were not smart enough to realise the benefits.

Lockheed...the BEST there is, positively without exception.
Others may well disagree of course, but until you have actually FLOWN the TriStar, you would have no idea.

It truly is one remarkable jet transport airplane.
Bar none.

Yes, yes, Lockheed is the best civilian aircraft manufacturer in the world.. That's why they went out of business  Yeah sure. I know you love your Tristar so much, but that does not mean other aircraft is not as good or even better than Tristar. It is simply just different design philosophy.

Cheers,
PP
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Tri-jets Single Engine Capability

Sun Jul 02, 2006 3:47 pm




Quoting 411A (Reply 47):
Lockheed...the BEST there is, positively without exception.
Others may well disagree of course, but until you have actually FLOWN the TriStar, you would have no idea.

Watch yourself, 411A....you're dangerously close to living up to that aforementioned "arrogant prick" description...  Wink

To a certain extent, I agree that one must have actually flown the Tristar to form a truly educated opinion regarding it's flight characteristics.

By the same token, however, one must have flown every other transport-category aircraft ever built for such a proclamation...that one of them is "positively the best"...to be truly accurate and authoritative.

You're a smart guy with a ton of experience, 411A, but your "positively", "without exception" comment is surprisingly undisciplined for someone at your level.




2H4


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