COOLING - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL

1. General
The power plant cooling system consists of :

cooling of the nacelle compartments
cooling of the aircraft and engine accessories
cooling of engine parts (HPT, HPC, LPT, ECU)

A. Nacelle Compartment Cooling
The nacelle is divided in three major areas

the engine air inlet
fan compartment
core compartment.

The functions of the nacelle compartments are :

(1) Sufficient airflow to offset the effects of engine case heat rejection and engine flange air leakage thereby maintaining an acceptable compartment temperature level.

(2) Cooling of temperature critical components.

(3) Cowling pressure load limiting in the event of pneumatic duct failures.

(4) Ventilation of compartment during engine shutdown.

(5) Ventilation of combustible fluid vapors to preclude fires.

B. Aircraft and Engine Accessories Cooling
The nacelle installation is designed to provide cooling and ventilation air for engine accessories mounted on the fan and core casing.
The distribution and circulation of the air in the compartments is such that the limit for specific components is not exceeded.

C. Cooling of Engine Parts
Different parts of the engine are cooled by air bled from the primary flow (HPTACC, RACSB), secondary flow (LPTACC). A scoop in the air intake cowl enables cooling of the ECU by ram air.

** ON A/C NOT FOR ALL

2. Location of Components

A. Location of High Pressure Turbine Active Clearance Control (HPTACC) System

HPTACC System Location ** ON A/C NOT FOR ALL

The HPTACC valve is located on the HPC compressor case at 3 o'clock (aft looking forward).

B. Location of Low Pressure Turbine Active Clearance Control (LPTACC) System

LPTACC System Location ** ON A/C NOT FOR ALL

C. Location of Rotor Active Clearance Control and Start Bleed System(RACSB).

RACSB System Location ** ON A/C NOT FOR ALL

D. Location of ECU cooling system

ECU Cooling System Location ** ON A/C NOT FOR ALL

[Rev.10 from 2021] 2026.04.01 03:10:01 UTC