Power Assurance Check [CFMI]

TASK 71-00-00-710-008-A
Power Assurance Check

CAUTION: DO NOT MAKE FAST ACCELERATIONS OR DECELERATIONS. DO NOT REMAIN AT THE MAXIMUM POWER ASSURANCE SETTING FOR MORE TIME THAN IT IS NECESSARY.

ZONE: 400

1. Reason for the Job
This procedure gives instructions to make sure the engine can produce the necessary takeoff thrust in line with EGT and N2 limits when setting N1.
The Power Assurance Check is not a good test for performance analysis of the engine. Do not use only the Power Assurance Check to accept or reject an engine. The Power Assurance run is usually not sufficiently stable to accurately determine the engine's health. You can get a more reliable performance analysis by doing a test cell operation or on-wing performance trend monitoring.

NOTE: When the Power Assurance Check is being done after maintenance, an accel/decel from idle to Maximum Power Assurance, and then back, must be done. This will check the engine and its system integrity. This check can be done at the same time as the vibration check. The power setting used in this check is 50 percent power.

NOTE: If the engine parameters are out of the targets of the power assurance tables, repeat the power assurance check. The MPA check should not be used by itself as a primary reason for engine replacement

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	THERMOMETER
98F10103500000	2	CHOCK-MLG,ENGINE RUN-UP

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
400	POWER PLANT, NACELLES AND PYLONS

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 71-00-00-710-003-A	Engine Automatic Start
TASK 71-00-00-710-028-A	Engine Shutdown
TASK 71-00-00-869-001-A	Abnormal Operation and Emergency Procedures
TASK 71-00-00-869-005-A	Wind Limitations During Engine Ground Operations
TASK 71-00-00-869-006-A	Safety Precautions During Engine Ground Operations
TASK 72-00-00-200-003-A	Procedure After the Engine has Exceeded the Operational Limits
Preferred Relative Wind Direction and Velocity Limitations For Power Settings of 90 Percent N1 RPM
Tool Installation
Results Sheet
50 Percent Power Assurance Setting

3. Job Set-up
Subtask 71-00-00-861-083-A ** ON A/C NOT FOR ALL

A. Energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-861-002).

Subtask 71-00-00-865-127-A ** ON A/C NOT FOR ALL

B. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	L/G/LGCIU/SYS1/NORM	1GA	C09
121VU	HYDRAULIC/LGCIU/SYS2	2GA	Q35
121VU	HYDRAULIC/LGCIU/SYS1/GRND SPLY	52GA	Q34

Subtask 71-00-00-869-286-A ** ON A/C NOT FOR ALL

C. Preparation for Test

WARNING: MAKE SURE THAT ALL ENGINE OPERATING AREAS ARE AS CLEAN AS POSSIBLE. ALL RAMPS, TAXIWAYS, RUNWAYS AND OTHER OPERATING AREAS MUST BE VERY CLEAN TO PREVENT BAD DAMAGE TO THE ENGINE, AIRCRAFT AND PERSONS IN THE AREA.

WARNING: DO NOT TRY TO STOP THE FAN FROM TURNING BY HAND. THIS CAN CAUSE INJURY TO THE PERSONS AND DAMAGE TO THE EQUIPMENT.

WARNING: MAKE SURE THAT THE LANDING GEAR GROUND SAFETIES AND THE WHEEL CHOCKS ARE IN POSITION. MOVEMENT OF THE AIRCRAFT CAN BE DANGEROUS.

WARNING: DO NOT DO AN ENGINE RUN-UP WITH THE THRUST REVERSER COWLS OPEN. IF YOU OPERATE THE ENGINE AT MORE THAN IDLE, THE FAN COWLS MUST NOT BE OPEN. IF YOU DO NOT OBEY THESE INSTRUCTIONS, INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT CAN OCCUR.

WARNING: - ENGINE OPERATION MUST NOT EXCEED MINIMUM IDLE WHEN PERSONNEL ARE IN ENTRY/EXIT CORRIDOR.

POSITIVE COMMUNICATION BETWEEN THE FLIGHT COMPARTMENT AND PERSONNEL IN ENTRY EXIT CORRIDOR IS NECESSARY.
INLET AND EXHAUST HAZARD AREAS MUST BE STRICTLY OBSERVED BY PERSONNEL IN ENTRY/EXIT CORRIDOR.

WARNING: MAKE SURE THAT:

THE PASSENGER DOORS ARE CLOSED AND THE PASSENGER LOADING STAIRS ARE REMOVED WHEN AT LEAST ONE ENGINE IS OPERATED ABOVE IDLE POWER.
THE CARGO DOORS ARE CLOSED AND CARGO LOADING EQUIPMENT IS REMOVED WHEN:

. ENGINE 2 IS OPERATED AT IDLE OR ABOVE . AT LEAST ONE ENGINE IS OPERATED ABOVE IDLE POWER IF YOU DO NOT OBEY THESE PRECAUTIONS INJURY TO THE PERSONNEL AND DAMAGE TO THE AIRCRAFT AND/OR EQUIPMENT CAN OCCUR.

CAUTION: OPERATION AT MINIMUM IDLE IN ICING CONDITIONS IS PERMITTED FOR EXTENDED PERIODS. IF THE CONDITION CONTINUES FOR MORE THAN 30 MINUTES , OR IF IMPORTANT ENGINE VIBRATION OCCURS; YOU MUST INCREASE THE ENGINE SPEED TO 70 PERCENT N1 MINIMUM FOR APPROXIMATELY 15 SECONDS BEFORE YOU SELECT A HIGHER THRUST OPERATION.

(1) Obey the wind limitations and safety precautions during engine ground operation (Ref. AMM TASK 71-00-00-869-005) and (Ref. AMM TASK 71-00-00-869-006).

Preferred Relative Wind Direction and Velocity Limitations For Power Settings of 90 Percent N1 RPM ** ON A/C NOT FOR ALL

CAUTION: MAKE SURE THAT THE AIRCRAFT IS PARKED ON A CLEAN, DRY AND FLAT SURFACE. THERE MUST BE NO OIL, GREASE OR SIMILAR MATERIALS ON THE SURFACE. THE PAVEMENT MUST NOT BE BROKEN OR LOOSE, AND WE RECOMMEND CONCRETE MATERIAL BECAUSE ASPHALT CAN MELT AND CAUSE DAMAGE TO THE AIRCRAFT.

(2) Make sure that the 98F10103500000 CHOCK-MLG,ENGINE RUN-UP are in position in front of each forward outboard MLG wheel.

Tool Installation ** ON A/C NOT FOR ALL

(3) Make sure that there is a minimum of 6014 lb (2728 kg) of fuel in the inner tanks to make sure that the aircraft is stable during the test.

NOTE: This minimum fuel quantity does not include the fuel consumption of the engines necessary to do the test. This minimum quantity must stay in the inner tank at the end of the test.

(4) There must be two qualified persons in the cockpit when performing an engine run. One must monitor the outside and the aircraft behavior while the other performs the engine test.
(5) If the aircraft begins to move while performing an engine run, immediately set all the thrust levers to the idle position.
(6) Make sure that the engine inlet and exhaust covers are removed. Make sure that these areas are clear of unwanted objects.
(7) Make a visual check of the temperature sensors, fan inlet and exhaust areas. If snow or ice has collected in the fan duct, make sure that the fan turns freely. Also, make sure that the engine inlet, inlet lip, fan, spinner and fan exhaust duct are clear of ice or snow. If the fan does not turn freely melt the ice or snow with hot air before an engine operation.
(8) Look at the general condition of the fan spinner and fan blades, core exhaust nozzle, Low Pressure Turbne (LPT) and external surfaces of the cowls.
(9) Do a check of the oil quantity. Make a check of the drain ports for fuel, oil and hydraulic leaks. Also make sure that fuel drained from the engine does not cause a fire.
(10) Measure and write down the outside air temperature Outside Air Temperature (OAT) and the barometric pressure. Make sure that it is accurate
(a) Put a THERMOMETER in the shade of the nose gear well to measure the OAT or request the data to the airport tower.

NOTE: If it is not possible to get the OAT, it is possible to use the Total Air Temperature (TAT) indication from the Air Data Computer (ADC) (shown on the ECAM system).

NOTE: Use the Power Assurance Results sheet.

Results Sheet ** ON A/C NOT FOR ALL

(11) On the ADIRS CDU (overhead panel 20VU), set the three OFF/NAV/ATT selector switches to NAV.
(12) On AIR COND panel 30VU:
(a) Release the ENG 1(2) BLEED pushbutton switch (the OFF legend comes on).
(13) On ELEC panel 35VU:
(a) Release the GEN 1(2) pushbutton switch (the OFF legend comes on).

Subtask 71-00-00-710-177-A ** ON A/C NOT FOR ALL

D. Start the two engines and let them become stable at minimum idle (Ref. AMM TASK 71-00-00-710-003).

Subtask 71-00-00-869-287-A ** ON A/C NOT FOR ALL

E. Find the N1 target values for the temperature that you measured in paragraph C:

50 Percent Power Assurance Setting ** ON A/C NOT FOR ALL

(1) Write down the altitude above sea level on the results sheet to aid in troubleshooting, if it become necessary. If not available set the BARO to 29.92 (regardless of actual pressure) and read the pressure altitude on the PFD altimeter.

4. Procedure
Subtask 71-00-00-710-189-A ** ON A/C NOT FOR ALL

A. If the N1 target will be more than or equal to 75 percent do this procedure:

WARNING: DO NOT LET ONE ENGINE OPERATE AT N1 GREATER THAN OR EQUAL TO 75 PERCENT WHEN ONLY THE WHEEL CHOCKS AND THE PARKING BRAKE STOP THE MOVEMENT OF THE AIRCRAFT.

(1) Slowly accelerate the non tested engine to 60 percent

CAUTION: DO NOT OPEN LGCIU CIRCUIT BREAKERS 1GA, 2GA AND 52GA. IF YOU DO THIS, AIRCRAFT BRAKING THROUGH BRAKE PEDALS DOES NOT OPERATE.

(2) On the landing gear control and indicating panel 402VU :
(a) Make sure that the A/SKID & N/W STRG selector switch 5GG is set to on.
(3) Make sure that the PARKING BRAKE control switch is in ON position.
(4) Push and hold the brake pedals at the full limit position.
(5) On the RUB TRIM/PARKING BRK panel 110VU:

set the PARKING BRAKE control switch to OFF

Subtask 71-00-00-710-178-A ** ON A/C NOT FOR ALL

B. Do the power assurance check
(1) Slowly accelerate the tested engine to within plus or minus 0.5 percent of the N1 target that you found for 50 percent power. Let the engine speed become stable for 4 minutes to warm up the engine.

EXAMPLE: With OAT at 25 deg. C, the target N1 is 72.4 percent plus or minus 0.5 percent.

NOTE: If the engine exceeds the operational limits, do the inspection procedure (Ref. AMM TASK 72-00-00-200-003).

NOTE: If abnormal operation occurs, do necessary abnormal or emergency procedure (Ref. AMM TASK 71-00-00-869-001).

(2) Decrease the tested engine speed to a minimum idle. Let it become stable for 3 minutes. Write down these parameters to aid in troubleshooting, if necessary: N1, N2, and EGT.
(3) Increase engine speed to within plus or minus 0.5 percent of the N1 target that you found for 50 percent power. Let it become stable for 4 minutes. Write down these parameters N1, N2, EGT and OAT or TAT.

	Target/Limit	50 % Engine 1
N1 %	72.4	73
N2 %	93.5	91.3
EGT C	637	588
Air Temp C	25

EXAMPLE: Recorded values N1 = 73 percent, N2 = 91.3 percent, EGT = 588 deg. C.
(4) Slowly decrease the engine speed to minimum idle let the engine power become stable for 5 minutes then stop the engines.
(5) Put the aircraft in the "parking-brake applied" configuration:
(a) On the RUD TRIM PARKING BRK panel 110VU:

Set the parking brake control switch to ON.

(b) Release the brake pedal.
(6) Compare the actual N1 to the target N1 value and adjust the actual N2 and EGT values as follows:
(a) For each 0.1 percent that the actual N1 value is different from the target N1 value, adjust the data as follows:
1 N2 ........... 0.05 percent
2 EGT .......... 1 deg. C

EXAMPLE: Recorded N1 was 73 percent, wich is 0.6 percent above the target N1. The multiplying factor for the adjustments is 0.6/0.1 = 6. The N2 adjustment is 6 * 0.05 = 0.30 percent. The EGT adjustment is 6 * 1 = 6 deg. C.
(b) If actual N1 is more than the N1 target, subtract the adjustments from the actual N2 and EGT.

EXAMPLE: Since recorded N1 was more than target N1, you must subtract the adjustments:
1 N2 adj. = 91.3 - 0.30 = 91.0 percent
2 EGT adj. = 588 - 6 = 582 deg. C
(c) If actual N1 is less than the target N1, add the adjustments to the actual N2 and EGT.
(7) Compare the data collected during power assurance check to the permitted limits.

50 Percent Power Assurance Setting ** ON A/C NOT FOR ALL

EXAMPLE: Enter Ref. Fig. at OAT or TAT of 25 deg. C
EGT MAX = 637 deg. C and N2 MAX = 93.5 percent
These limits are for a CFM56-5A3 rated engine.
(a) Identify adjustments for EGT and N2 as a function of engine rating (for example, 5A4) from the table below :

CFM56-5A Model Conversion Requirements

Convertion To	N2 Margin Required	Delta EGT Margin Sea Level
A1/A1F	0	11
A3	0	0
A4/A4F	0	9
A5/A5F	0	4

EXAMPLE: The engine rating of interest is the CFM56-5A4. The EGT adjustment is 9 degrees and the N2 adjustment is 0 percent.
(b) Add the adjustments to EGT MAX and N2 MAX to find the limits for the engine rating.

EXAMPLE: Limits for a CFM56-5A4 engine
EGT MAX adj = 637 + 9 = 646 deg. C
N2 MAX adj = 93.5 + 0 = 93.5 percent
(c) Compare data collected during power assurance check to the limits. The margins calculated in this step will apply to sea level takeoffs.

EXAMPLE: EGT MAX adj. = 646 deg. C and N2 MAX adj. = 93.5 percent
EGT MARGIN (EGT MAX adj. - EGT adj.) = 646 - 582 = 64 deg. C
N2 Margin (N2 Max adj. - N2 adj.) = 93.5 - 91.0 = 2.5%

CAUTION: TAKEOFFS AT ALTITUDE MAY REQUIRE GREATER EGT MARGIN THAN AT SEA LEVEL.

(8) Adjust the EGT margin for altitude effect.
If the aircraft regulary operates at airports above 0 feet (sea level), an adjustment to the calculated EGT margin may be needed. The table below shows altitude adjustments to sea level EGT margin for various ratings.

No adjustment for the 5A1 rating is necessary since altitude EGT margin is equal to or greater than sea level EGT margin.
5A3, 5A4 and 5A5 ratings will require adjustment per the following table for altitudes above sea level. Adjustment values are either read directly from the table or are interpolated if the desired altitude lies between table entries. Always use the worst-case (most negative) value for the altitude range being considered.

EXAMPLE: For the 5A4 engine at 4000 feet above the sea level.
According to the table below, the 5A4 EGT margin is lower by 15 degrees at 5000 feet and is lower by 0 degrees at 0 feet. Using interpolation, the adjustment at 4000 feet is:
EGT margin adj. = (-15 - 0) * (4000 - 0) / (5000 - 0) + 0 = -12
EGT margin at 5000 feet = 64 - 12 = 52 deg. C

Adjustments for Altitude of Takeoff

Model	Airport Altitude	EGT Margin C
CFM56-5A1	na	na
CFM56-5A3	Up to 3000 feet	0
	4000 feet	-8
	5000-8000 feet	-20
	10000 feet	8
CFM56-5A4	Sea level	0
	5000-8000 feet	-15
	10000 feet	-12
CFM56-5A5	Sea level	0
	5000-8000 feet	-15
	10000 feet	-9

(a) If the adjusted values for EGT and N2 are less than the maximum limits (if EGT and N2 margin are positive numbers), the engine will make target N1 and not be more than the EGT or N2 limits. No more power assurance testing is necessary if this occurs.
(b) If the data is not in line with limits, let the engine become stable at idle for 4 minutes and do the power assurance check again at the same power level.
(c) If the data is still not in line with the limits after a second engine run, investigate the reported fault messages in the Trouble Shooting Manual.

CAUTION: IF THE DATA COLLECTED IS NOT IN LINE WITH THE PERMITTED LIMITS, THE ENGINE MAY GO OVER THE EGT OR N2 LIMIT AT TAKEOFF POWER.

(d) If cause is found and corrected, do the power assurance check again.
(e) If the engine exceeds EGT or N2 limits in normal operation after two test runs and after troubleshooting per the TSM has been completed, engine replacement should be considered. The power assurance check should not be use by itself as a primary reason for engine replacement.
(9) Stop the engines (Ref. AMM TASK 71-00-00-710-028).

5. Close-up
Subtask 71-00-00-869-288-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) On the AIR COND panel 30VU:
(a) Push the ENG 1(2) BLEED pushbutton switch (the OFF legend goes off).
(2) On the ELEC panel 35VU:
(a) Push the GEN 1(2) pushbutton switch (the OFF legend goes off).

Subtask 71-00-00-862-077-A ** ON A/C NOT FOR ALL

B. De-energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-862-002).

Subtask 71-00-00-210-080-A ** ON A/C NOT FOR ALL

C. Do a visual inspection of the engine, the engine inlet and exhaust areas.
(1) Make a visual walk around inspection of the engine, include the engine inlet and exhaust areas.

[Rev.10 from 2021] 2026.04.01 02:21:30 UTC