PPRuNe Forums - View Single Post - SATA brand new A320 ; hard landing in Lisbon
Old 21st Aug 2009, 08:10
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cwatters
 
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You can calculate the minimium g if you know the vertical velocity and the "stopping distance". The stopping is roughly the vertical undercarriage travel.

From the equations of motion..

V^2 = U^2 + 2aS

V = final vertical velocity (hopefully zero)
U = Initial velocity (rate of descent at contact)
a = acceleration (will be negative in this case)
S = displacement (undercarriage travel)

This makes a lot of assumptions but it gives the minimium g that will be experienced. In practise the shock absorber won't be linear and I guess it may "bottom out" under high load. That would increase the g considerably.

"a" will be in meters per second. Needs to be divided by 9.8 to get a "g" ratio.

Edit: Report shows this to be irrelevant though. The peak g occured in the air.

Last edited by cwatters; 21st Aug 2009 at 08:43.
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