What Happens if a 777 Loses An Engine? Or Both?

[keithplya9]

Ok, so a few weeks the Qantas A380 going from LA to Australia had then engine die and so it turned around. Ok cool, cuz they have 3 other engines still.... but what happens if you're flying a 777 across the Pacific and an engine goes out? Or what if both engines go? There no land anywhere and i don't know if a large plane like that could coast on a single engine.

Anyone know the science behind why a long distance plane like a 777 that flies over oceans all the time only as 2 instead of 4 engines? and what happens when one goes?

 

[anat0l]

Not an expert here, but this is what I "know".

Planes are "designed" so that in cases where they are down to half the engines they have, they can still be flown. Naturally, some adjustments need to be made to the flying technique, but the main thing is that there is still adequate control over the aircraft (notwithstanding any other unknown or more serious impediments).

At that point, a diversion airport should be found. Flight pathing takes into account that there will always be a diversion field within some given amount of time (ETOPS specification gives some bounds on the time limits that such an airport should always be away from the flight path).

Mind, just because a 4-engine plane can run on 2 or 3 engines, doesn't mean it can necessarily continue all the way to its destination more than a 2-engine plane. Airlines have weighed up the economics and chances of failure / diversion, i.e. 2-engine planes burn less fuel, hence the savings made may outweigh the costs of any recovery if a scenario like an engine failure were to arise.

Now if all engines get killed, then I suppose you'd better hope your Captain is good at piloting a glider......

 

[mannej]

You don't think the 2 engine planes wouldn't be certified to fly these routes if they couldn't handle flying on one engine.
As for losing two engines, it is an extremely rare event.

 

[TomVexille]

Ok, so a few weeks the Qantas A380 going from LA to Australia had then engine die and so it turned around. Ok cool, cuz they have 3 other engines still.... but what happens if you're flying a 777 across the Pacific and an engine goes out? Or what if both engines go? There no land anywhere and i don't know if a large plane like that could coast on a single engine.

Anyone know the science behind why a long distance plane like a 777 that flies over oceans all the time only as 2 instead of 4 engines? and what happens when one goes?

It's less science than economics. Two engines are cheaper to run than four.

You would be surprised at the amount of land between the east coast of Australia and the USA.

 

[ermen]

It's less science than economics. Two engines are cheaper to run than four.

You would be surprised at the amount of land between the east coast of Australia and the USA.

Airstrips are what I'm more concerned about

 

[TomVexille]

Airstrips are what I'm more concerned about

Well a 777 will never be more than 180 minutes away from a suitable airstrip when flying MEL-LAX

 

[keithplya9]

180 minutes is almost 3 hours away... can a plane stay in the air if its engine is damaged for that long?

 

[sampson]

Are Floaties carry-on or check in?

 

[keithplya9]

haha! Ok look look, I've flown over oceans before. Im not afraid of flying or anything. I was just curious as to what would happen is a two- engined plane were to <have inflight mechanical issues>

 

[TomVexille]

180 minutes is almost 3 hours away... can a plane stay in the air if its engine is damaged for that long?

Any plane that is certified ETOPS 180 can most certainly fly for 3 hours on a single engine. Boeing offer up to ETOPS 330 for the 777

 

[markis10]

180 minutes is almost 3 hours away... can a plane stay in the air if its engine is damaged for that long?

Planes can stay in the air and even climb with just one engine. Events that affect more than one engine normally affect all, so it that scenario it does not matter how many engine you have.

 

[eric2011]

You would be surprised at the amount of land between the east coast of Australia and the USA.

No arguing that but How much of that land has a runway of approx 8000 ft to land and 11000 ft for a 777 to take off again once the problem has been fixed.
Is there much land between say New Caledonia or Fiji, and Hawaii, and then Hawaii and LAX. Both those legs would be over 5 hours or so wouldn't they. ? If a 777 had a problem half way between what would the pilot do with trim, altitude, etc, etc

 

[mannej]

haha! Ok look look, I've flown over oceans before. Im not afraid of flying or anything. I was just curious as to what would happen is a two- engined plane were to **** up

What do you think would happen? The pilots do train for situations such as this, so they would be well prepared.

In fact here is an example from the other day.

Incident: Korean B773 over Pacific on Jul 2nd 2013, engine shut down in flight

 

[HodgoBerro]

I think there was an Air NZ flight headed for LAX back in March that had to divert to Honolulu due to an engine issue. As an av geek I was always under the impression that if one engine dies it doesn't give the plane enough thrust to keep in a straight line.

 

[dmitri]

180 minutes is almost 3 hours away... can a plane stay in the air if its engine is damaged for that long?

Is there a difference between 3hrs and 180 mins?

 

[straitman]

No arguing that but How much of that land has a runway of approx 8000 ft to land and 11000 ft for a 777 to take off again once the problem has been fixed.
Is there much land between say New Caledonia or Fiji, and Hawaii, and then Hawaii and LAX. Both those legs would be over 5 hours or so wouldn't they. ? If a 777 had a problem half way between what would the pilot do with trim, altitude, etc, etc

eric2011,
I suggest you google up what ETOPS and the associated numbers mean as it appears to me that you have not picked up on that yet.

ETOPS 180 (for example) means that the a/c is not allowed to be more than 180 minutes from a suitable airfield when travelling on one engine so the 5 hours comment would never come into play.

Also another minor consideration is that an aircraft with 4 engines has twice as much chance of having an engine failure.

 

[eric2011]

Thank you, not all of us are aircraft savvy and until a few minute ago I had never heard about ETOPS etc. That's the good thing about a forum like this. People with a little knowledge help and advise people with no knowledge.
No the 5 hours wouldn't come into play but the next line of my question relates to half of that time ie 2 1/2 hours and what would a pilot do re altitude etc

 

[straitman]

Thank you, not all of us are aircraft savvy and until a few minute ago I had never heard about ETOPS etc. That's the good thing about a forum like this. People with a little knowledge help and advise people with no knowledge.

That is why I suggested you google as you will probably get a better summary and quicker than you from multiple Q&A here. Have you looked at the ask the pilot thread :?:

No the 5 hours wouldn't come into play but the next line of my question relates to half of that time ie 2 1/2 hours and what would a pilot do re altitude etc

The pilot would do what ever was called for by the aircraft flight manual. This would vary considerably between situations (weather & weight etc) and with a/c types and performance.

 

[DC3]

... Also another minor consideration is that an aircraft with 4 engines has twice as much chance of having an engine failure.

... and will have three times as many engines still running, if one engine goes out.

 

[keithplya9]

Ok so what about flights from like Frankfurt to San Fran that fly over the arctic. Do they have staffed runways thru Northern Canada and Greenland just in case something happens in a remote area like that?