How long can a jumbo glide for?

Question

They say it will fly with one engine but if the worst happened could it glide? I think it will do you?

Answer 1

A 737 glides about 3 miles for every thousand feet of altitude. So from 33,000, it would glide 100 miles.

The 767 referenced below did 11:1 glide ratio so that would be 85 miles from 41,000 feet. But that 11:1 wasn't at an optimized speed from the book, because Boeing hadn't written that into the book yet.

The A330 referenced below went from 34,500 and 85nm out to 13,000 feet and 8nm out from Lajes. So 90 statue miles dropping 21,500 feet or a glide ratio of 22:1.

In a non-fuel starvation situation (rare, those turbines rarely stop working), a plane flies further with full fuel on board. Counter-intuitive until you think how it has more potential energy and yet the same form drag to overcome.

Answer 2

Great answers Bunaby and DivaDiane, here is some more info:

Older planes have flight engineers (like me) and newer ones have computers, which provide the pilots with all sorts of information. One of these bits of info is "driftdown" speeds and power settings. Of course, this is just based on losing one engine on a multi-engine aircraft. Upon losing an engine the power setting would be set and the airspeed attained. Then a descent would be made to a predetermined altitude. If all engines were out, there would still be a "driftdown" speed that would result in the best distance covered with the least altitude lost per nautical mile. Although people like to say large airplanes would drop like a "brick" or "coke machine" it is just not true. Furthermore, planes like the 707 and 727, need no hydraulics or electrics to safely fly. The DC-10 needs its hydraulics, but a Ram Air Turbine could be deployed in the event of a loss of all engines and this would provide enough electricity to power a hydraulic pump.

Answer 3

Many great answers above. Actually, most airplanes will glide a surprisingly far distance. Some answers above said that larger airplanes don't glide as far. That isn't true because larger airplanes also have proportionally larger wings, larger airfoils, etc. that compensate for its larger and heavier size.

In the C-5 Galaxy, we routinely practice approaches and landings with two engines out on one side of the airplane, which can be quite challenging. There are several factors that determine the all engine-out glide distance, however, most of which have been discussed by earlier answers.

Answer 4

Good rule of thumb: with no engines, 20 feet forward for every one foot down. So, from 35000 feet, or 7 miles, at least 100 miles of glide (just to be on the safe side).

Look up an Air Transat flight that set the record for the longest glide by a commercial airliner.

Answer 5

Don't forget a Jumbo weighs in at about 300 tons with a full payload. It travels at 5- 600 mph which means it will probably glide for a few miles ....then fly like a brick.

Answer 6

The 747 is an amazing aircraft and will fly with one engine. Not well but it will stay airborne. However if all power is lost it has the glide characteristics of a brick. Hydraulics would be lost making the control surfaces unusable

Answer 7

A 747 has a glide ratio of about 15:1. From normal cruising altitude it has about a 100 mile glide radius.

Answer 8

I actually have heard of an Airbus A320 (i think that was the type) that was owned by TransAlta airlines that lost all of its power, due to a fuel leak, that glided to a landing somewhere in the atlantic ocean. Total gliding time was about 20 minutes

Answer 9

The next time you fly and you feel the Aircraft start to descend, chances are that you are in a big glider. We do most descents at idle power. The 737 goes down somewhere between 1000-2000 feet per minute at optimal glide speed.

Answer 10

It depends on varying conditions. On August 24, 2001, a two engine Airbus A330 jetliner glided 70 miles from FL350 to a safe landing at Lajes, Portugal. This was due to fuel exhaustion. If you have other aviation questions, email me at [e-mail]. I'm a pilot.