Your colleague may be considering the ramp characteristics of the said bump, the relative value of the horizontal and vertical impulse loads experienced by the aircraft as it transits the bump, the lift distribution and pitching moment characteristics of the aircraft at the point of transit, aircraft centre of mass, spring characteristics of wheels and undercarriage assemblies ... as these will influence the net moment generated about the mainwheels - only part of which is due to the bump itself.
Is the aircraft pitching prior to the transit due to pilot control inputs ? if the aircraft is a typical highlift wing taildragger, then maybe there isn't much load on the wheel assemblies at the point in the takeoff roll which you are considering ?
.. the list goes on ... and, like most such questions, the devil is in the detail ...
Last edited by john_tullamarine; 21st August 2002 at 10:17.