Jabiru Aircraft
Pilot Operating Handbook
Model J170-D
JP-FM-13
Revision:
0
1
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28 Feb 2020
Page 0-12
•
Airfield Pressure Height
–
The height registered at the surface of an aerodrome by an
altimeter with the pressure sub-scale set to 1013 hPa (29.92 inches Hg).
•
Pressure Altitude
–
Altitude measured from standard sea-level pressure (1013 hPa/29.92
inches Hg) by a pressure or barometric altimeter corrected for position and instrument error.
•
Indicated Pressure Altitude
–
the altitude actually read from an altimeter when the pressure
barometric sub-scale has been set to 1013 hPa (29.92 inches Hg).
•
QNH
–
The local pressure setting that if set on the subscale of an altimeter will cause the
altimeter to indicate local altitude above mean sea level.
•
Wind
– The wind velocities to be used as variables on aircraft performance are to be
understood as the headwind or tail wind components of the reported winds.
Aircraft Performance and Flight Planning Terminology
•
Climb Gradient
– The ratio of the change in height during a climb, to the horizontal distance
travelled.
•
Demonstrated Crosswind Component
– The crosswind component, during take-off and
landing, for which adequate control of aircraft was actually demonstrated during certification
tests.
Weight and Balance Terminology
•
Datum
–
An imaginary vertical plane from which all horizontal distances are measured for
balance purposes.
•
Station
–
A location along the aircraft fuselage usually given in terms of distance from the
reference datum.
•
Arm
–
The horizontal distance from the reference datum to the centre of gravity (C of G) of
an item.
•
Moment
– The product of the weight of an item multiplied by its arm.
•
Index Unit
– Moment divided by a constant. Used to simplify balance calculations by
reducing the number of digits.
•
Centre of Gravity
(C of G)
– The point at which an aircraft would balance if suspended. The
distance from the C of G to the reference datum can be found by dividing the total moment
by the total weight of the aircraft.
•
C of G Arm
– The arm obtained by adding the aircraft's individual moments and dividing the
sum by the total weight.
•
C of G Limits
–
The extreme centre of gravity locations within which the aircraft must be
operated at a given weight.
