Pilot Flying protection factor Peak Flow Plantar Flexion Power Factor powered flight Packet Filter Packing Fraction Parity Flag Payload Forward Phenol - formaldehyde pico farad plantarflexion Potency Factor Presentation Function prime function probability of failure pulse frequency pulverized fuel French Polynesia Frigate PAGE FORMATTER Parachute Facility partition factor Patrol Frigate Payload Function PBX Function peak frequency pemphigus foliaceus Performance Factor