By: wysiwyg - 22nd September 2002 at 15:38
RE: Time to divert !!!
Those figures give a glide ratio of 20:1 which I would say is just about spot on!
By: SOFTLAD - 21st September 2002 at 19:27
RE: Time to divert !!!
Right not seen any of the Airbus lads to ask but i was chatting to one of the Boeing guys and he said from FL370 the B757-200 would glide around 120nm.So that does seem to be a bit more realistic than the Airbus figures i got told.
Regards,
Lyndon.
By: SOFTLAD - 16th September 2002 at 11:14
RE: Time to divert !!!
That is interesting.Next time im in work i will ask again and put those figures to the pilots.Ill let u know what they say.
Regards,
Lyndon.
By: Hand87_5 - 16th September 2002 at 10:36
RE: Time to divert !!!
[updated:LAST EDITED ON 16-09-02 AT 10:36 AM (GMT)]very interesting , thanks wysiwyg !!
By: wysiwyg - 16th September 2002 at 09:50
RE: Time to divert !!!
I’m afraid to say that those figures just aren’t possible. The highest performance competition glider has a glide ratio (distance forward to distance down in still air) of about 60:1. Therefore the best glider can go 60 nautical miles forward for 1 nautical mile (6080′) of altitude. Therefore in 1000′ the glider will only achieve 10nm. The captain being quoted is implying a glide ratio of nearly 150:1. The most efficient soaring bird (the albatross) is claimed to have a glide ratio of 20:1, which incidentally is the same figure as was quoted for the TriStar.
Glide ratio is in actual fact irrelevant in most multiple engine failure scenarios as the first priority is to get an engine going again. As there is currently no bleed air supply available to power the starter motors the only way to start the engines is to do a windmill start which requires the nose to be lowered to achieve a speed of typically 300 knots. This will give enough airflow through the engine to hopefully allow the engine to accelerate when fuel and ignition are added to the equation. Obviously if you have run out of fuel (doh!) there is no point going for a relight but then you probably wouldn’t know that fuel starvation was the cause of the failure or you would have done something about it sooner.
Hope this helps.
By: Hand87_5 - 14th September 2002 at 15:07
RE: Time to divert !!!
Interesting. Thanx.
By: SOFTLAD - 14th September 2002 at 14:53
RE: Time to divert !!!
Spoke to a Captain at work and he said the best possible glide ratio for the A330-200 is 24nm for every 1000ft u desend.Thats a long way if your up at 41,000ft.
By: KabirT - 13th September 2002 at 09:52
RE: Time to divert !!!
agreed with EGNM on his points.
By: EGNM - 13th September 2002 at 09:49
RE: Time to divert !!!
Not sure of the exact distance but i think the Air Transat A330 was one of the longest into Lages in the Azores after a failure over the atlantic. The key is to first transfer speed into altitude – at that altitude probably means trying to keep that height for an extra few mins, thenthe most efficient glideslope – this is probably at a low speed and high angle of attack, but the wing mustn’t be stalled or u’ll be desending a lot fast than intended!!! It is well know that due to the design of modern day airliners they can be very efficient gliders, the problem been gliders usually stay close to home as opposed to halfway accross the atlantic!!!
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September 13, 2002 at 9:34 am