Our Aircraft and The Centre of Gravity

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Nic Cremonte Skydive Robertson

NNP is a front door exit aircraft, pretty obvious but with it comes a particular problem. The centre of gravity and how it changes as people exit the plane.
Simplistically most aircraft fly best when the weight in the fuselage is concentrated under the wing and distributed evenly to the front and back of it. When the plane is loaded with 6 skydivers and gear that is quite a bit of weight indeed.
Andre d'Argent Chief Instructor Skydive RobertsonMost skydivers know to get the weight forward and under the wing for takeoff. So we all scrunch up no matter how hot it is and stay that way to about 1000ft and the aircraft is at speed. All pretty common sense stuff……but what about exit. Not many people give a thought about exit. The plane is flying fine, high and we are about to jump. What can go wrong?
Exit can be as dangerous as take off if the centre of gravity is not correct, that is, under the wing. The plane is throttled back to slow down and give a comfortable climb out. As a result it is flying much closer to its stall speed than it would during the climb or cruise. Skydivers hanging off her cause drag and slow things down even further.
As the first group of skydivers lets go their weight is no longer there and the centre of gravity immediately moves to the rear where the next group is kneeling. Out from under the wing and towards the tail. So now you are slow and have an unbalanced mass dragging down the tail. This is stall territory. Not only is it stall territory but if the aircraft stalls with all that weight in the tail the pilot is going to have one hell of a time trying to recover, if he can at all. As for you the jumper you will not be able to help, stalls can be violent and you will be having some ‘stuck in a washing machine’ problems of your own. So if you are not the first to go, stack it up. Move forward immediately when the previous group goes. I know it is fun but this is not the time to be high fiving each other. You should have got that out of the way about a minute prior. Keep the weight under the wing, keep safe and keep the pilots blood pressure below 200.

Have fun folks, and DFU.