Aeronautical Terms beginning with P
P-Factor
A tendency for an aircraft to yaw to the left due to the for descending propeller blade on the right producing more thrust than the ascending blade on the left. This occurs when the aircraft’s longitudinal axis is in a climbing attitude in relation to the relative wind. The P-factor would be to the right if the aircraft had a counterclockwise rotating propeller.
Parasite Drag
That part of total drag created by the design or shape of airplane parts. Parasite drag increases with an increase in airspeed.
Payload
(GAMA) Weight of occupants, cargo, and baggage.
Permanent Ballast (fixed ballast)
A weight permanently installed in an aircraft to bring its center of gravity into allowable limits. Permanent ballast is part of the aircraft empty weight.
Phugoid oscillations
Long-period oscillations of an aircraft around its lateral axis. It is a slow change in pitch accompanied by equally slow changes in airspeed. Angle of attack remains constant, and the pilot often corrects for phugoid oscillations without even being aware of them.
Pilot’s Operating Handbook (POH)
An FAA-approved document published by the airframe manufacturer that lists the operating conditions for a particular model of aircraft and its engine(s).
Piston Engine
A reciprocating engine.
Pivotal Altitude
A specific altitude at which, when an airplane turns at a given groundspeed, a projecting of the sighting reference line to a selected point on the ground will appear to pivot on that point.
Planform
The shape or form of a wing as viewed from above. It may be long and tapered, short and rectangular, or various other shapes.
Porpoising
Oscillating around the lateral axis of the aircraft during landing.
Position Lights
Lights on an aircraft consisting of a red light on the left wing, a green light on the right wing, and a white light on the tail. CFRs require that these lights be displayed in flight from sunset to sunrise.
Positive Static Stability
The initial tendency to return to a state of equilibrium when disturbed from that state.
Potable Water
Water carried in an aircraft for the purpose of drinking.
Power
Implies work rate or units of work per unit of time, and as such, it is a function of the speed at which the force is developed. The term “power required” is generally associated with reciprocating engines.
Power Distribution Bus
A Bus Bar. An electrical power distribution point to which several circuits may be connected. It is often a solid metal strip having a number of terminals installed on it.
Power Lever
The cockpit lever connected to the fuel control unit scheduling fuel flow to the combustion chambers of a turbine engine.
Powerplant
A complete engine and propeller combination with accessories.
Practical Slip Limit
The maximum slip an aircraft is capable of performing due to rudder travel limits.
Precession
The tilting or turning of a gyro in response to deflective forces causing slow drifting and erroneous indications in gyroscopic instruments.
Preignition
Ignition occurring in the cylinder before the time of normal ignition. Preignition is often caused by a local hot spot in the combustion chamber igniting the fuel/air mixture.
Preventive maintenance
Simple or minor preservative operations and the replacement of small standard parts not involving complex assembly operation as listed in 14 CFR part 43, appendix A. Certificated pilots may perform preventive maintenance on any aircraft that is owned or operated by them provided that the aircraft is not used in air carrier service.
Profile Drag
The total of the skin friction drag and form drag for a two-dimensional airfoil section.
Propeller
A device for propelling an aircraft that, when rotated, produces by its action on the air, a thrust approximately perpendicular to its plane of rotation. It includes the control components normally supplied by its manufacturer.
Propeller Blade Angle
The angle between the propeller chord and the propeller plane of rotation.
Propeller Lever
The control on a free power turbine turboprop that controls propeller speed and the selection for propeller feathering.
Propeller Slipstream
The volume of air accelerated behind a propeller producing thrust.
Propeller Synchronization
A condition in which all of the propellers have their pitch automatically adjusted to maintain a constant r.p.m. among all of the engines of a multiengine aircraft.
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