Cold Weather Operation Procedure [IAE]

TASK 71-00-00-700-014-B
Cold Weather Operation Procedure

1. Reason for the Job

Ice that can collect at the engine inlet is one of the primary problems during engine operations in cold weather.
Engine icing can cause the conditions that follow:
. rotor blades that are caught against the stator case
. a rotor system that is not balanced
. internal damage in the engine.
These conditions add to the engine icing problem:
. rotor blades and blade tips that have ice attached and is caused from:
* Snow that melts and freezes again on the engine rotors and stators during engine cool-down.
* Engine suction during engine operation. This action decreases the air pressure which causes the air temperature to decrease. This condition is more apparent during high power static ground runs in stable weather conditions.
* Evaporating cooling.
. Collected ice that goes in to the engine nacelle during engine operation.

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TASK 71-00-00-710-043-A	Normal Engine Automatic-Start Procedure
TASK 71-00-00-710-047-A	Normal Engine Manual-Start Procedure

3. Job Set-up
Subtask 71-00-00-869-271-A ** ON A/C NOT FOR ALL

A. Not Applicable

4. Procedure
Subtask 71-00-00-869-272-A ** ON A/C NOT FOR ALL

A. Cold Weather Operation Procedure

CAUTION: DO NOT OPEN THE FAN COWL DOORS AND THE THRUST REVERSER COWLS WHEN THE EXTERNAL TEMPERATURE IS LESS THAN -40 DEG.C (-40 DEG.F). IF YOU DO, COLD CONDITIONS CAN CAUSE DAMAGE TO THE FAN-COWL AND THRUST-REVERSER ACTUATORS.

(1) Before engine operation:
(a) Remove the engine inlet and the exhaust covers.
(b) Remove all the loose ice and snow from the engine inlet ducts, exhaust ducts and the engine external surfaces.
(c) Make sure that there is no fluid around the exhaust area that will burn.
(d) Turn the fan blades:

WARNING: USE APPLICABLE GLOVES WHEN YOU TOUCH THE FAN BLADES. THE LEADING EDGES OF THE FAN BLADES ARE SHARP AND CAN CAUSE INJURY.

1 Make sure that the N1 rotor will turn freely. Use your hand and turn the rotor in a counterclockwise direction when you look to the rear of the engine.
(e) Apply heat (a maximum of 176 deg.F (80 deg.C)) if you have one or more of the conditions that follow:
1 The rotors do not move because of ice.
2 There are ice and snow on the cowling, external surfaces, joints of the thrust reverser, inlet cowl acoustic panels, fan duct and turbine exhaust duct.
3 The oil temperature is less than -40 deg.F (-40.00 deg.C). Warm air must be blown inside the nacelle to raise the indicated oil temperature to -40 deg.F (-40.00 deg.C) or warmer before the start-up.
(2) Start the engine. Use the normal engine automatic start procedure (Ref. AMM TASK 71-00-00-710-043) or the normal engine manual start procedure (Ref. AMM TASK 71-00-00-710-047).

WARNING: DO NOT VISUALLY EXAMINE THE INLET COWL FOR ICE WHEN THE ENGINE IS IN OPERATION. DO NOT GO NEAR THE INLET AREA OR INJURY TO THE PERSON CAN OCCUR.

(a) Apply engine/nacelle thermal anti-icing if you have the conditions that follow:
1 There is visible moisture such as clouds, fog, rain, snow, sleet or ice crystals present and the outside Static Air Temperature (SAT) is less than 42 deg.F (5.6 deg.C) or if the dew point and the Outside Air Temperature (OAT) (ram air temperature (RAT) or SAT) are in 5 deg.F (-15 deg.C) or 3 deg.C (37.4 deg.F) of each other.
2 There are bad icing conditions:

CAUTION: DURING GROUND RUNNING, CONCERN FOR FAN BLADE INTEGRITY PROHIBITS STABILISED ENGINE OPERATION IN THE FOLLOWING SPEED RANGE:

FOR PRE-SCN17/V A/C: DO NOT STABILISE THE ENGINE BETWEEN 61% TO 74% N1 SPEED RANGE
FOR POST-SCN17/V A/C (IAE SERVICE BULLETIN V2500-ENG-73-0184) STABILISED OPERATION OF THE ENGINE BETWEEN APPROXIMATELY 60% TO 74% N1 SPEED RANGE (LIMITS ARE A FUNCTION OF OUTSIDE TEMPERATURE) WILL BE PROHIBITED BY THE EEC, AS THE SOFTWARE INCLUDES THE KEEP-OUT-ZONE FOR ON-GROUND, STATIC OPERATION. THEREFORE, THE PILOT MAY NOTICE A DIFFERENCE IN ENGINE POWER RESPONSE COMPARED TO AN ENGINE WITH PRE-SCN17/V SOFTWARE. REFER TO IAE SERVICE BULLETIN V2500-ENG-73-0184 FOR MORE DETAILS.

a Do a regular engine run-up (with the engine anti-icing system on) to the highest thrust setting possible (50 percent N1 speed for a minimum of 15 seconds is necessary). This must be done to keep to a minimum the risk of ice build-up during the extended ground idle operation. Ten minutes is the minimum time necessary between each engine run-up.
(3) After engine shutdown:

CAUTION: THE ENGINE MUST BE SHUTDOWN IN THE FORWARD THRUST POSITION DURING A SNOW STORM. FAILURE TO DO THIS CAN CAUSE ICE TO BUILD UP ON THE CASCADE VANES OF THE THRUST REVERSER, THE BLOCKER DOORS AND THE LINKAGES.

(a) Make sure that there is no snow or ice on the aircraft parking area.
(b) Examine the engine intake areas for ice particles:
1 Remove all the ice during the engine cool-down time.
(c) After the engine is cool:

CAUTION: IF ICE AND WATER ARE NOT REMOVED FROM THE ENGINE INTAKE, THE LOWER FAN BLADE TIPS CAN FREEZE TO THE FAN CASE.

1 Make sure that there is no ice or water in the engine intake at the lower fan section area.
2 Apply a light coat of anti-icing fluid to the engine surfaces that will contact all the applicable engine covers.

NOTE: The engine covers will not freeze to the engine when the anti-icing fluid is applied.

3 Install all the engine covers.

NOTE: The installation of the engine covers will give protection to the engine from ice, rain and snow.

[Rev.10 from 2021] 2026.04.01 02:28:11 UTC