AIR CONDITIONING AND PRESSURIZATION
Operation
Aircraft Operations Manual
2.2
PAGE
2
Jun 01/17
2.
NORMAL OPERATION
2.1
CARGO COMPARTMENT TEMPERATURE V.S. FLYING TIME, FL AND OAT
Cargo compartment temperature varies with OAT at the departure airport, cruising level OAT, FL and
duration of flight. In general, as can be seen in below graphs there is a slight temperature increase in the
cargo compartment
How to use the charts
1.
Establish a REFERENCE TEMPERATURE: when OAT at departure airport and at cruising level deviates
from ISA, use the lowest temperature (variation from ISA) as REFERENCE TEMPERATURE.
2.
Follow the line for the REFERENCE TEMPERATURE until intersect with the FLYING TIME and find the
CARGO COMPARTMENT TEMPERATURE.
Example:
Departure Airport OAT
+15
°
C (ISA)
. . . . . . . . . .
Cruising Level
FL 200
. . . . . . . . . . . . . . . . .
Cruising Level OAT
−
30
°
C (ISA
−
5
°
C)
. . . . . . . . . . . . .
Flying time
1 hr 5 min.
. . . . . . . . . . . . . . . . . . . .
Since ISA
−
5
°
C (
−
30
°
C) at cruising level is colder than ISA (+15
°
C) temperature at the departure airport,
the ISA
−
5
°
C shall be used as REFERENCE TEMPERATURE to establish cargo compartment tempera-
ture.
Answer:
Lowest cargo compartment temperature will be about +1
°
C.
A10251
FLYING TIME
−
MINUTES
CARGO
COMPARTMENT
TEMPERATURE
(
C )
20
40
60
80
100
120
+20
+10
0
−
10
REFERENCE TEMPERATURE = ISA
REFERENCE TEMPERATURE = ISA
−
10¯C
REFERENCE TEMPERATURE = ISA
−
15
°
C
FL 100
(Cont’d)