boeing 747

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17 years 10 months

Posts: 68

Hi could some 1 help can a 747 fly on 1 engine ??
also if its flying at 33.000 ft and lost all power would it glide over 1200 miles
hope somebody can help thanx in advance

Original post

Member for

17 years 4 months

Posts: 1,060

I remember watching a Seconds from disaster type documentart about a BA 747 flying through some sort of Volcano dust / ash storm and all 4 shut down and managed to glide some distance before the crew got all four burning again. Anyone else remember anymore details? I think it was out the far east somewhere. Bex

Member for

18 years 11 months

Posts: 8,847

I remember watching a Seconds from disaster type documentart about a BA 747 flying through some sort of Volcano dust / ash storm and all 4 shut down and managed to glide some distance before the crew got all four burning again. Anyone else remember anymore details? I think it was out the far east somewhere. Bex

Yes it was.

http://aviation-safety.net/database/record.php?id=19820624-0

The Air Transat 330 glided 85 miles from 13,000 feet.

http://aviation-safety.net/database/record.php?id=20010824-1

Member for

19 years 11 months

Posts: 92

Hi could some 1 help can a 747 fly on 1 engine ??
also if its flying at 33.000 ft and lost all power would it glide over 1200 miles
hope somebody can help thanx in advance

Someone mentioned this on The travel city direct forum recently!!

Member for

17 years 4 months

Posts: 1,060

Thanks I was sure I wasnt loosing me marbles just yet. All I can say is I could handle loosing 3 engines, but all 4? Stuff that, talk about brown trousers time, one brave crew on that BA flight. Bex

Member for

18 years 7 months

Posts: 5,530

I remember watching a Seconds from disaster type documentart about a BA 747 flying through some sort of Volcano dust / ash storm and all 4 shut down and managed to glide some distance before the crew got all four burning again. Anyone else remember anymore details? I think it was out the far east somewhere. Bex

I believe it was over New Zealand, but I could be wrong!

A 747 could possibly, if at cruising altitude stay in the air on only one engine, although I imagine it would create some rather interesting asymmetric thrust problems if it were either engine No.1 or No.4. If it lost all four it would certainly come down after much less distance than 1200 miles. I would imagine 120 miles would be a more reasonable figure, although I'm more than willing to be corrected!

Paul

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18 years 11 months

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I believe it was over New Zealand, but I could be wrong!

Yes, you are, see Post 3.

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20 years 7 months

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A 744 as with any plane could potentially stay in the air on one engine, but if you take a 747 for example that is cruising at FL350 and it lost 3 engines, the issue here is whether this engine will be able to create enough thrust to remain in the air at that altitude, (the engine is set to max continuous power), the answer is no it can't (normally), so there is a thing called a driftdown procedure that is used whereby it can (not that it has a choice) descend to an altitude whereby the air is dense enough to produce the required thrust.
This means that, as the aircraft descends, the thrust increases and the driftdown angle becomes progressively shallower until it reaches zero and the aircraft stabilises. The driftdown angle becomes steeper at heavier weights and the heavier the a/c is the lower the stabilising altitude.

The driftdown is flown at the best angle of climb speed, VX, which is VIMD (minimum drag speed) for a jet and is also the best (least) angle of descent speed.

This procedure is particulary problematic if the driftdown altitude is lower than say The Alps etc.

Hope this helps

Dean

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20 years 7 months

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also if its flying at 33.000 ft and lost all power would it glide over 1200 miles
hope somebody can help thanx in advance

FLYBYDONNI

It wouldn't be able to glide 1200 miles, that's here to North Africa

If an a/c wanted to glide for best range then it will fly at the best lift:drag ratio which is Vimd or velocity for minimum drag, if we remain here the glide angle will remain the same, however if the a/c is heavy then Vimd will be higher by a factor proportional to the square root of the weight increase.
So if we increase speed to a new Vimd the only thing that changes is the time in the air, you should maintain the same glide angle and the same distance covered on the ground, you'll just meet the ground a bit quicker.
This is for still wind conditions, if we had a headwind then the best result would come by increasing your speed, the opposite for a tailwind.
There are graphs to work out the best speed to fly in certain conditions.

The 744 as with any plane will have a glide ratio worked out from the above, it could be something like 1:10, this means for every 1,000ft lost in height it will travel 10,000ft horizontally, again if you do the maths 33,000ft will give a Horizontal distance of 330,000ft which works out about 63 miles in still wind conditions.

Hope this helps too

Dean

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20 years 7 months

Posts: 2,623

The Air Transat 330 glided 85 miles from 13,000 feet.
http://aviation-safety.net/database/record.php?id=20010824-1

Newforest

Mate the Air Transat glided 21,500ft in 77nm (or 88.5 statute miles) to end up at 13,000ft 8nm from the runway threshold. This is a glide ratio of about 1:21 which is excellent.

Dean

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20 years 11 months

Posts: 12,842

British Airways Flight 9, sometimes referred to as the Jakarta incident, was a scheduled British Airways flight from London Heathrow to Auckland, with stops in Bombay, Madras, Kuala Lumpur, Perth and Melbourne. On 24 June 1982, the route was flown by City of Edinburgh, a 747-200 registered G-BDXH. The aircraft flew into a cloud of volcanic ash thrown up by the eruption of Mount Galunggung, resulting in the failure of all four engines, although the reason for the failure was not then apparent to the crew or ground control. The aircraft was diverted to Jakarta in the hope that enough engines could be restarted to allow it to land there. The aircraft was able to glide far enough to exit the ash cloud, and all engines were restarted (although one failed again soon after), allowing the aircraft to land safely.

Member for

20 years 1 month

Posts: 115

will a 747 fly on 1 engine?

well, yes and no,
it is totally weight dependant. using the 747-2 if it is empty or close to, yes, it can make it around the pattern, in a case where you lose the other three prior to an established final,
it will not maintain level flight with the gear down on one, so you have to be on or above the glide, loc established and on your way down, it will not go around, so gear down is a commitment.
Two engine work in the SIM is done at weights of approx 195 T, usually with the loss of the first one at or just beyond V1, and the second in the pattern prior to intercept of the Final app crs. To be honest not much is gained by trying single engine work in the sim.
The loss of multiple engines at ALT if heavy will require fuel dumping asap.

driftdown as mentioned is generally computed on an enroute card, usually at 10 ton intervals, or on the hour, based on the loss of one, it is a three engine drift down ALT, the speed to best accomplish this, and the power setting (EPR/N1) required, max con for the weight and altitude.
essentially the procedure on the loss of one is the balance to max cont, allow the speed to decay to the computed drift down speed, and start down on that speed to the computed DD ALT, which is "should" maintain.

Keep in mind that as weight decreases, it is quite possible that you can not only maintain the chosen cruise ALT on 3, but actually still climb, if the "driftdown" ALT computed for the weight shows you can maintain a higher alt that your existing cruise.

regards all engine out glide, at idle thrust the engines still produce about 55% thrust, so the 3 to one rule is pretty accurate, 3 times your alt is the distance you will go, 33000 ft - 100 miles, but remove all that residual thrust, this no longer applies, and you will decrease this, again weight dependant, heavy the airplane will glide further, light, it will glide less, but a rough figure, at normal landing weights, (under 285.7) I would not expect to get any better than 85 DME.

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18 years 11 months

Posts: 8,847

Newforest

Mate the Air Transat glided 21,500ft in 77nm (or 88.5 statute miles) to end up at 13,000ft 8nm from the runway threshold. This is a glide ratio of about 1:21 which is excellent.

Dean

Cheers mate, thanks for the correction!:)

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17 years 10 months

Posts: 68

Someone mentioned this on The travel city direct forum recently!!

I was reading it on the tcd forum thats why i asked

Member for

19 years 11 months

Posts: 313

Newforest

Mate the Air Transat glided 21,500ft in 77nm (or 88.5 statute miles) to end up at 13,000ft 8nm from the runway threshold. This is a glide ratio of about 1:21 which is excellent.

Dean

Well, it was flying with empty fuel tanks at that stage, wasn't it!

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18 years 6 months

Posts: 3,718

Newforest

Mate the Air Transat glided 21,500ft in 77nm (or 88.5 statute miles) to end up at 13,000ft 8nm from the runway threshold. This is a glide ratio of about 1:21 which is excellent.

Dean

The Transat also converted some speed. Basically the glide ratio of an A330 even exceeds 1:21, but under those conditions with wind-milling engines it wouldn't achieve more than I think 14 - 18. With all conservatisms the glide ratio can be assumed 1:10 for an airliner, which then includes some margin. The aerodynamic glide ratio is normally much better (B747-200 is about 1:18, up to 1:20), but the drag of the engines and the external turbine, non-optimal trim and the normal difference between wind tunnel data and real life performance reduces glide efficiency.

And I agree Deano, it can not fly on one engine except maybe for some very remote conditions (basically empty).

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20 years 7 months

Posts: 2,623

Well, it was flying with empty fuel tanks at that stage, wasn't it!

Makes no difference, see post #9, adding weight only makes you reach the ground quicker, i.e. a higher rate of descent, the glide angle & distance travelled along the ground (glide ratio) is the same

Member for

19 years 11 months

Posts: 170

Maybe there was 2 BA747 volcanic dust incidents.
I am sure there was one over the African continent.
All four engines also failed and then restarted I think it was in darkness.
The crew found a small airfield with no navaids and runway lighting partly missing. The cockpit windscreen had been shotblasted and the captain landed the aircraft manually looking out of the side window.
Does anyone else remember this?
wawkrk

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18 years 7 months

Posts: 5,530

Makes no difference, see post #9, adding weight only makes you reach the ground quicker, i.e. a higher rate of descent, the glide angle & distance travelled along the ground (glide ratio) is the same

I'm totally confused as to how you can have a higher rate of decent but have the same glide angle and travel the same distance. Sorry, Deano, my poor little brain isn't understanding!

Is there any way reply 9 can be explained in a different way so that stupid and simple people like me can vaguely comprehend it? :confused:

Paul

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18 years 8 months

Posts: 4,721

Newforest

Mate the Air Transat glided 21,500ft in 77nm (or 88.5 statute miles) to end up at 13,000ft 8nm from the runway threshold. This is a glide ratio of about 1:21 which is excellent.

Dean

Isnt that the world record for flying with no engines the A330 Air Transat one?

James

Member for

18 years 11 months

Posts: 8,847

Maybe there was 2 BA747 volcanic dust incidents.
I am sure there was one over the African continent.
All four engines also failed and then restarted I think it was in darkness.
The crew found a small airfield with no navaids and runway lighting partly missing. The cockpit windscreen had been shotblasted and the captain landed the aircraft manually looking out of the side window.
Does anyone else remember this?
wawkrk

You are describing the Jakarta incident unless you are confused with the Air Canada 767 incident on 23/7/83 where the plane glided 45 miles from 35,000 feet to land at Gimli.

http://aviation-safety.net/database/record.php?id=19830723-0