the Aviation Dictionary

program flowchart propeller critical range
program flowchart - A chart (such as Pert or Gnatt)
that shows the steps to be taken in the execution of a
program.
programmable calculator - An electronic calculator
that can be programmed by the user. Programming is
usually stored in its memory.
programmable indicator data processor - The PIDP
is a modification to the ANITPX-42 interrogator
system currently installed in fixed RAPCONs. The
PIDP detects, tracks, and predicts secondary radar
aircraft targets' These are displayed by of
computer-generated syn~bols and alphanumeric
characters depicting flight identification, aircraft
altitude, ground speed, and flight plan data. Although
primary radar targets are not tracked, they are
displayed coincident with the secondary radar targets
as well as with the other symbols and alphanumerics.
The system has the capability of interfacing with
ARTCCs.
programmable read-only memory (PROM) - An
integrated circuit memory device for a digital
computer. Programmable read-only memory can be
modified once by the user. This is called "burning" the
PROM. Thereafter, the PROM acts the same as readonly
memory (ROM). A computer with erasable
programmable read-only memory (EPROM) or
electrically erasable programmable read-only memory
(EEPROM) can be modified more than once.
progress report - A report over a known location as
transmitted by an aircraft to ATC.
progressive inspection - An inspection identical in
scope and detail to an annual inspection, but which
allows the workload to be divided into smaller portions
and performed in shorter time periods. This allows the
aircraft to remain airworthy and in service during the
extensive (sometimes up to a year long) inspection
period.
progressive taxi - Precise taxi instructions given to a
pilot unfamiliar with the airport or issued in stages as
the aircraft proceeds along the taxi route.
prohibited area - A prohibited area is airspace
designated under part 73 within which no person can
operate an aircraft without the permission of the using
agency.
prohibited area [ICAO] - An airspace of defined
dimensions, above the land areas or territorial waters of
a State, within which the flight of aircraft is prohibited.
projection - A defense mechanism used by students to
relegate blame for their own shortcomings, mistakes,
and transgressions to others, or to attribute their
motives, desires, characteristics, and impulses to other
people.
prony brake - A device used to measure the usable
power output of an engine on a test stand. It consists
largely of a hinged collar, or brake, that can be
clamped to a drum splined to the propeller shaft. The
collar and drum form a friction brake that can be
adjusted by a wheel. An arm of known length is
attached to the collar and terminates at a point that
bears on a scale. As the propeller shaft rotates, the
force is measured on the scale. This force multiplied by
the lever arm indicates the torque produced by the
rotating shaft.
proof load - 1. A load applied to a structure that does
not cause permanent deformation. 2. A testing measure
to insure the structure will be airworthy.
proof pressure test - A series of tests to show that a
pressure capsule will withstand the pressure exerted
upon it in service.
prop blast - The colloquial term for the rush of air
generated by a propeller.
- - - -
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 anti-icer - A system within an airplane that
meters a flow of alcohol and glycerine along the
leading edge of the propeller blades to prevent the
formation of ice on the blades.
propeller blade - The part of a propeller that forms the
airfoil and converts the torque of the engine into thrust.
propeller blade angle - The acute angle between the
chord of a propeller blade and the plane of rotation.
propeller blade pitch - The distance a propeller will
advance if there isn't any slip.
propeller blade tipping - The thin sheet brass or
stainless steel covering along the leading edge and
around the tip of a wooden propeller that protects the
blade from erosion.
propeller boot - A propeller cuff that fits around the
base of the propeller blade and causes increased
airflow into the engine air inlet for cooling.
propeller boss - The thick, central portion of a
fixed-pitch propeller hub.
propeller brake - A friction brake used on
turbopropeller engines to prevent the propeller
windmilling in flight after it has been feathered.
propeller butt - The blade shank or base of the
propeller blade that fits into the propeller hub.
propeller critical range - An operational range where
engine speed will cause harmonic vibration in the
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