Propeller Feather
This is a propeller pitch condition which produces minimum drag
in a flight condition (engine shutdown).
Propeller Speed Control
Mode
Propeller speed control is the principle operating mode of the
propeller control system while the aircraft is operating in flight.
The propeller control system modulates the propeller blade
angle in order to govern on the selected propeller reference
speed.
T1
Indicated T1 temperature is used to calculate the engine power.
On ground and during initial takeoff/climb T1 is based on the
engine inlet temperature sensor reading, corrected to represent
ambient temperature. 400 ft above ground level T1 is based on
average data from aircraft Outside Air Temperature (OAT)
sensors.
Tachometer
An instrument that indicates rotational speed. Gas generator
tachometers measure speed as a percentage of the nominal
maximum speed of the turbine(s), while propeller tachometers
measure actual propeller rpm.
Torquemeter
An indicating system that displays the output torque available on
the propeller shaft. Torque is shown in reference terms, such as
the oil pressure generated by the engine torquemeter piston.
1-5-5
Airplane Performance and Flight Planning Terminology
Climb Gradient
The demonstrated ratio of the change in height during a portion
of a climb, to the horizontal distance traversed in the same time
interval.
Demonstrated Crosswind
Velocity
The demonstrated crosswind velocity is the velocity of the
crosswind component for which adequate control of the airplane
during takeoff and landing was actually demonstrated during
certification tests. The value shown may or may not be limiting.
Whether or not the value shown is limiting will be stated.
MEA
Minimum Enroute IFR Altitude.
Route Segment
A part of a route. Each end of that part is identified by: (1) a
geographical location; or (2) a point at which a definite radio fix
can be established.
1-5-6
Weight and Balance Terminology
A.O.D.
Aft of Datum
Arm
The horizontal distance from the reference datum to the center
of gravity (C.G.) of an item.
Basic Empty Weight
Standard empty weight plus optional equipment.
Center of Gravity (C.G.)
The point at which an airplane would balance if suspended. Its
distance from the reference datum is found by dividing the total
moment by the total weight of the airplane.
C.G. Arm
The arm obtained by adding the airplane's individual moments
and dividing the sum by the total weight.
C.G. Limits
The extreme center of gravity locations within which the airplane
must be operated at a given weight.
Section 1 - General
Airplane Performance and Flight Planning Terminology
Pilot's Operating Handbook
Report No: 02406
Issue date: Mar 06, 2020
Page 1-5-4
12-C-A15-00-0105-00A-005A-A
FOR
GENERAL
AND
FAMILIARIZATION
PURPOSES
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