Silly question about 4 engined jets

[Rally]

Will most 4 engined jets like (airbus, dc-8 707, 747 etc) fly on one engine fully loaded? Or if gas is dumped with a full payload? Just curious people ask me this question occassionally and having never flown one I'm not sure.

Thanks

 

[MarineGrunt]

The KC-135 can fly (barely) on one engine at 200,000lbs. The heaviest I've taken off was about 280-290k and the lightest about 165k. We can dump 6k per min.

 

[slinky]

The 747 is a real handfull on two engines. At or near max landing wieght(630,000), which is pretty much where the freighters are because of the cargo load, it can fly on two but one is out of the question. A pax bird might be able to pull it off if it is light enough on one engine but it would not be a pretty sight.

 

[FDXer]

Will most 4 engined jets like (airbus, dc-8 707, 747 etc) fly on one engine fully loaded?

It will fly long enough to take you to your crash site. Without dumping a lot of fuel in a hurry, you're in trouble. Once as much fuel is dumped as possible, you might be able to maintain level flight or stay on a glidepath until landing. Don't plan on going anywhere far.

 

[pilotyip]

The joke on the P-3 (T56-10W) was it would fly on one engine, but it would run out of gas shortly there after.

 

[LJ45]

Geez...what is the Vmc if the only engine operating is #1 or #4 ?

 

[blueridge71]

Do you have to practice a V-1 cut-cut-cut?

 

[MarineGrunt]

Geez...what is the Vmc if the only engine operating is #1 or #4 ?

I don't think the numbers exist for the KC135. The flight manual says it WILL fly on one engine, but thats pretty much under ideal conditions. And you better have a light enough fuel load or your toast no matter what. I've done it in the sim a few times - each time the only operating engine was an inboard, and I died on about 50% of those. I'd imagine your goose is cooked with only one outboard engine. Hope I never have to find out!

I think there was a crash years ago where an USAF RC135/E8 or something similar took birds into all engines and lost all but a single OB engine. They didn't live to tell the story.

 

[JFReservist]

Marine Grunt is correct... the tanker (R-model) will fly on one engine (around 200000lbs). All my sims have been either #1 or #4 remaining. It sucks but you can land it. It won't dump very fast though with just one hydraulic pump remaining, and you'll need that for gear, and a few degrees of flaps. Real life? Screw that.

 

[Lead Sled]

The following story has been floating around for a long time, but it sort'a goes along with this thread. It seems that once upon a time a fighter pilot calling for a priority landing because his single-engine jet fighter was running "a bit peaked." ATC told the fighter jock that he was number two behind a B-52 that had one engine shut down. "Ahhhh," the pilot remarked, "the dreaded seven-engine approach."

 

[surplus1]

Those 135s that will 'fly on one engine' - which engines are they equipped with?

 

[Bubba Dog]

In the KC-135R, 2 engine approaches are generally not a problem,just push up the inboard,flaps at lowest setting(20),delay gear till GS intercept,feed in the outboard as necessary when more power is needed,can get the powered rudder back by crossing over,recommended in this case or for the gear. The tanker would hold 200,000 lbs of fuel and we always recommended 20,000 lbs of fuel(assuming basic crew and no pax or cargo) or less for 2 eng approach,and that was in case you needed to go around. Inflight min control rudder power operative is approach speed if my memory serves me correctly. All this means if you try to go around and need more power you just will not be able to hold a heading but will climb,eventually may roll over on your back,just use some common sense,don't make it to complicated. Just remember the KC-135A thrust was 50,000 lbs thrust(4 engines) with water injection and the KC-135R is 90,000 lbs of thrust(4 engines) up to 91 F at sea level so a R model on 2 engines is almost like a "A "model at 4 eng thrust. You can go -around starting at 200 AGL(R model) with only one engine(Inboard) at max go-around thrust with 12,000 lbs.fuel,SL,STD day,climbing about 500 fpm,if only outboard engine very iffy. On take off a sharp pilot with 80,000 lbs of fuel or less could make it on one engine(especially if it is an inboard),very,very minimum performance and must have thorough knowledge of systems and how thrust/drag interacts with each other.

 

[MarineGrunt]

Those 135s that will 'fly on one engine' - which engines are they equipped with?

CFM56

 

[Bubba Dog]

Those 135s that will 'fly on one engine' - which engines are they equipped with?

Both R and A model would do it depending on GW obviously.
R=CFM56
A= P&W and believe it or not Ford made some of their engines also

 

[surplus1]

Thanks. Civilian birds in my experience never had CFM56's. Real glad I never had to prove it could be done on a Pratt. Strikes me there's a whole lot of wishful thinking in that scenario (in the real world).

 

[Juniority]

That last (operating) engine on the KC-135 is a lot like the last (operating) engine on a Light Twin: It will take you all the way to the crash site.

CFM56-2B (22,000 pounds of thrust from the factory, derated to 20,000 for the Air Force to promote longevity). Add about 4 or 5 thousand hours on the wing, take a few small birds and other bits of FOD (at places like Manas and Al Udeid) with the required blending of fan blades, toss in some deterioration and subsequent delamination of the 460 MetCo coating in the compressor section stages, and you've got yourself a handful at 200,000 pounds.

 

[oldxfr8dog]

I hven't flown a DC-8 for over 10 years, but I know that (in a sim) if you lose one on after TO on a 3-engine ferry, you can clean up if you can have the VSI on zero for at least 10-15 miles. After your speed is 210 + it's just another airplane, as long as you don't have to go-around.
In the sim, I demonstrated to guys that a 1-engine approach can work if you're above the GS and can descend on it. Of course if you have to go around, just crash near the runway. Easier for the trucks to find you.

 

[retired guy]

Thanks. Civilian birds in my experience never had CFM56's. Real glad I never had to prove it could be done on a Pratt. Strikes me there's a whole lot of wishful thinking in that scenario (in the real world).

Delta`s DC 8 61s were refitted with CFM 56`s....a huge improvement.

 

[airplane wizard]

How many engines does a B52 need to maintain level flight?

 

[Some guy]

I think there was a crash years ago where an USAF RC135/E8 or something similar took birds into all engines and lost all but a single OB engine. They didn't live to tell the story.

They lost the 2 left engines. Very sad day / week.

http://www.geocities.com/Pentagon/5464/

RIP
SG

 

[PITA]

4 engines

My experience is with the 340. Both 300 and 500 models.

Engine failure at or just after V1 it is a hand full to say the least, and you had better hope you have a few hundred feet below you so you can get the nose down and accelerate and use ground effect in a worse case scenario on 2 engines.

The 4 engine A/C do not have to be certified to fly on 2 engines after a V1 cut since both the FAA and JAR certification criteria do not require it.

The A/C will yaw like crazy if one of the outboard engines quits, but is more than able to handle the takeoff. The 340 at max gross will not climb AND accelerate till at least cleaned up, and that is the most worry going on the long haul flights. Speed is your friend then.
We practice a lose of both engines on the same side and you need lots of room in front of you just to accelerate and get cleaned up.

Still both A/C are a pleasure to fly compared to the 330 IMHO. And the fact that you have 4 engines out there turning, is a comforting thought that even if you have an engine failure, it is not an automatic emergency, and you have plenty of time to make a decision, as there are more options open to you over a twin engine A/C.

On 1 engine the airplane will still fly, but will be flying down very low and you better hope it happened in cruise. And you had to be dumping fuel on the way down. I do not have the QRH or any charts available in front of me now, but it is sobering to say the least on 1 engine.

It still is an airplane and has different charecteristics than others, but respect what you have and just realize the limitations.
4 engines just give you different choices to make.

Now if they would just pay us more ................... that is another story.

 

[surplus1]

Delta`s DC 8 61s were refitted with CFM 56`s....a huge improvement.

Must have been nice. Ever heard of a civil 707 series refitted that way? I'm just curious. I've seen the military models but never a civil model.

 

[Benhuntn]

1 out board eng. working is easier to fly than two working on the same side. It's aero my man... Two engines out means you have two working unopposed thus the high VMCi. With three out the VMCi returns to the same as 1 eng. out. So if you are light enough flying a 1 eng app is no more difficult than flying a 1 eng. out.