This includes non-united fractures; non-reducible dislocations; united fractures and reduced dislocations with incomplete restoration of function; amputation of arm, hand, leg, or foot; loss of any skeletal portion of the thumb of either hand; loss of more than the two distal phalanges of the ring or little fingers of either hand; any lose joints; pes cavus, weak foot, or clubfoot; flatfoot with symptoms unresponsive to orthotics; loss or deformity of great toe or any two toes on the same foot; torn cartilage or loose foreign bodies within the knee joint; instability of the knee joint; or inadequately healed surgical procedure. Performs work at airfields handling aircraft (e.g., fighters, bombers, cargo, passenger) carrying large volumes of fuel, conventional and sometimes nuclear weapons, or highly flammable or explosive cargo; or handling a large number of air moves, or a moderate number involving pilot training, or other air moves with high crash or fire potential.