Ralphmalph is correct. Limitations are just that, limitations and are not to be exceeded. Military aircraft component overhaul times and lives are computed based on an aircraft usage spectrum that is negotiated between the military customer and the manufacturer. This is one area that tends to get complex when the actual usage spectrum differs from the one originally negotiated or changes throughout the life of the vehicle. As an example, the negotiated usage spectrum may call for one autorotative descent every 4 flight hours when in actuality an aircraft assigned to a training outfit may do many times that in the course of its life. This example was sighted as the cause for the premature failure of main gear box free wheeling units in aircraft used for training.