An airplane has run short of fuel and is trying to glide to an airport; will it pay to throw any weight?

Answer 1

For the purpose of reaching the airport (on a long glide), the change in weight will not make any significant difference to how far it can glide, except in the presence of a headwind or tailwind.

The reason for this is that the best glide angle is constant for an aircraft. However, the speed at which the airplane obtains the best glide angle varies with weight. You can visualize this as the gliding airplane travelling down an imaginary ramp. As the plane gets heavier, it travels down the ramp faster, and if it is lighter, the plane travels down the ramp slower.

Wind comes into play because the change of speed affects how long you will be gliding to get to the airport, and thus how long you will be exposed to the effects of the headwind or tailwind. Imagine that your "fast glide" at your maximum weight was 100mph, and your "slow glide" at your minimum weight was 50mph. If you wanted to reach an airport, but had a 50mph headwind, at your minimum weight, you wouldn't go anywhere relative to the ground!

So in summary...

Throw off weight when:
- You have a tailwind and you're trying to glide farther
- You need more time to evaluate options or ponder your fate =)
- You are over your maximum landing weight.

Keep the extra weight when:
- You have a headwind and you're trying to glide farther
- You want to glide to your destination faster.

Answer 2

Of course a lighter airplane will glide further, but good planning would have prevented the situation in the first place. Stretching a glide is not conducive to longevity, rather than throw stuff out and maybe kill some one on the ground, it would likely be a better option to just land where you can, farmers field, golf course, what ever. It also shouldn't be a surprise that you run out of gas on final, you have to fly with 45 minutes reserve fuel, so when you start dipping into that, it is seriously time to find a place to get more fuel.

Answer 3

You are asking about the trade-off between lift/drag and gravitational potential energy.

Although the sink rate is higher with a heavier plane the speed is higher again, so a heavier plane has more energy and glides further, though in less time.

Y'all aren't going to believe that, but that's the way it is. But here's a fact for you, competition gliders carry water ballast, the last thing they do after they cross the line is dump the water ballast as they pull up into their landing circuit, they no longer need the energy and they want a slower landing speed.

I am not certain this applies to slow little aircraft, but it is true for commercial aircraft and competition gliders.

See the little article below, it's a test of small gliders that shows that they glide further as weight increases until they reach their maximum operating weight after which glide distance decreases.

Answer 4

the lighter the plane, the greater the glide slope with no engine power (fuel). you could try to throw any extra weight off the plane, but that would mean opening a door and causing a sudden decompression of the aircraft putting your passengers at risk. i watched a Mayday episode one day where an Air Transat flight lost all fuel over the atlantic due to a fuel line rupture, it glided safely to a (hard) landing and everyone onboard survived.

Answer 5

Any aircraft carrying weight inside would have to open something to throw out the extra weight. Changing the configuration, ie., opening a door would result in drag and shorten the glide.

Answer 6

The fact of the matter when fuel runs out, you just got to sit down tighten you seat belts and pray that the pilot is an ACE! and what can you throw out,

if you throw out fat people like someone said in one article you what have to open the door and then suction would suck all of you out, so do nothing and like I said prey that you pilot is an ace but if he has made the aircraft run out of fuel he must be pretty good.

Answer 7

Aerodynamically, maybe

Realistically, no

In the presence of a strong headwind, you will need the weight to give you more penetration - the ability to drive yourself against the wind. Otherwise you could find yourself falling short of your destination. The main thing to do is maintain a minimum fuel burn, maintain max glide, and not panic.

Answer 8

Don't run short of fuel....

There are three things a pilot can't use:

The airspace above him
The fuel he did not put in his tanks
The airport behind him

Answer 9

the less weighed the plane is carrying the better for it to glide
but do not alter the aerodynamic of a gilding plane by opening
doors or hatches that can caused disturbed that will tilt the plane direction seriously

Answer 10

The lighter the load the more chance of a safe landing.