DOC AIRBUS | AMM A320FPower Assurance Check [CFML]
TASK 71-00-00-710-816-A
Power Assurance Check
This procedure gives instructions to make sure the engine can produce the necessary takeoff thrust in line with Exhaust Gas Temperature (EGT) and N2 limits when N1 is set. The power level used in this procedure is 72.5 percent.
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.
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Job Set-up
Subtask 71-00-00-861-117-A Subtask 71-00-00-865-195-A
Subtask 71-00-00-710-273-A
Subtask 71-00-00-860-260-A
[Rev.10 from 2021]
2026.04.01 12:58:04 UTC
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.
1. Reason for the JobThis procedure gives instructions to make sure the engine can produce the necessary takeoff thrust in line with Exhaust Gas Temperature (EGT) and N2 limits when N1 is set. The power level used in this procedure is 72.5 percent.
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: If the engine parameters are out of the targets of the power assurance table after a first test run, the power assurance check may be repeated. It is possible that engine replacement will be necessary by the conditions that follow:
Do not use the power assurance check as the only cause for engine replacement. - The engine continues to go above EGT or N2 limits during normal operation after two test operations.
- Troubleshooting has been completed by the instructions in the TSM without correction of the problem.
NOTE: The examples shown in this procedure are for these test conditions:
2. Job Set-up Information- Outside Air Temperature (OAT) = 25 deg.C (77 deg.F)
- N1 modifier for this engine = 2
- 72.5 percent power setting
- Altitude 4000 feet.
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| 98F10103500000 | 2 | CHOCK-MLG,ENGINE RUN-UP |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 12-31-71-660-803-A | Cold Weather Maintenance - Power Plant |
| 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 71-00-00-860-827-A | Start the Engine (Normal Automatic Start) |
| TASK 71-00-00-860-829-A | Engine Shutdown |
| TASK 71-00-00-869-802-A | Wind Limitations During Engine Ground Operations |
| TASK 71-00-00-869-803-A | Safety Precautions During Engine Ground Operations |
| TASK 71-00-00-869-804-A | Abnormal Operation and Emergency Procedures |
| TASK 72-00-00-200-818-A | Inspection/Check After the Engine has Exceeded the Operational Limits |
Tool InstallationSubtask 71-00-00-861-117-A Subtask 71-00-00-865-195-A
B. Make sure that this(these) circuit breaker(s) is(are) closed:
Subtask 71-00-00-860-258-A | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| 49VU | L/G/LGCIU/SYS1/NORM | 1GA | C09 |
| 121VU | HYDRAULIC/LGCIU/SYS2 | 2GA | Q35 |
| 121VU | HYDRAULIC/LGCIU/SYS1/GRND SPLY | 52GA | Q34 |
C. Preparation for Test
(3) Make sure that a total of 3000 kg (minimum) of fuel are in the inner tanks to make sure that the aircraft is stable during the test.
(5) If the aircraft begins to move while performing an engine run, immediately set all the thrust levers to 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) Examine 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 (Ref. AMM TASK 12-31-71-660-803).
(8) Examine the general condition of the fan spinner and fan blades, core exhaust nozzle, Low Pressure Turbine (LPT) and external surfaces of the cowls.
(9) Check for correct oil quantity . Examine 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 OAT.
(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 71-00-00-970-067-A 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:
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 71-00-00-869-802) and (Ref. AMM TASK 71-00-00-869-803). 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 is in position in front of each forward outboard Main Landing Gear (MLG) wheel. (3) Make sure that a total of 3000 kg (minimum) of fuel are 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 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) Examine 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 (Ref. AMM TASK 12-31-71-660-803).
(8) Examine the general condition of the fan spinner and fan blades, core exhaust nozzle, Low Pressure Turbine (LPT) and external surfaces of the cowls.
(9) Check for correct oil quantity . Examine 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 OAT.
NOTE: Example: OAT = 25 deg.C (77 deg.F).
NOTE: It is also possible to use the Total Air Temperature (TAT) indication from the ADC (shown on the ECAM system).
(11) On the overhead panel 20VU on the ADIRS CDU, 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).
D. Find the N1 target values for the temperature that you measured.
Subtask 71-00-00-860-259-A NOTE: Example: N1 Target = 73.7 percent
(1) Make a record of the altitude above sea level on the results sheet to aid in troubleshooting, if it becomes necessary. If not available, set the BARO to 29.92 and read the pressure altitude on the Primary Flight Display (PFD) altimeter. NOTE: Example: Altitude = 4000 feet.
E. Start the two engines and let them become stable at minimum idle for 3 minutes minimum (Ref. AMM TASK 71-00-00-860-827).
4. ProcedureSubtask 71-00-00-710-273-A
A. Do the following steps:
(2) On the landing gear control and indicating panel 402VU:
(b) Make sure that the PARKING BRAKE control switch is in ON position.
(3) Push and hold the brake pedals at the full limit position.
(4) Perform the power assurance check per Para. 4.B.
(5) After test completion, release the brake pedals to put the aircraft in the "parking-brake applied" configuration.
Subtask 71-00-00-710-274-A 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 50 percent N1. (2) On the landing gear control and indicating panel 402VU:
CAUTION:
DO NOT OPEN LGCIU CIRCUIT BREAKERS 1GA, 2GA AND 52GA. IF YOU DO THIS, AIRCRAFT BRAKING THROUGH BRAKE PEDALS DOES NOT OPERATE.
(a) Make sure that the A/SKID & N/W STRG selector switch 5GG is set to ON. (b) Make sure that the PARKING BRAKE control switch is in ON position.
(3) Push and hold the brake pedals at the full limit position.
(4) Perform the power assurance check per Para. 4.B.
(5) After test completion, release the brake pedals to put the aircraft in the "parking-brake applied" configuration.
B. Do the power assurance check
(1) Increase the tested engine speed to within plus or minus 0.5 percent of the N1 target that you find for 72.5 percent power. Let it become stable for four minutes to warm up the engine.
(3) Increase the tested engine speed to within plus or minus 0.5 percent of the N1 target that you found for 72.5 percent power. Let it become stable for four minutes. Write down these parameters N1, N2, EGT, altitude and OAT or TAT.
(4) Slowly decrease the tested engine speed to minimum idle.
(5) Adjust the measured EGT for removal of EGT trim in cockpit displayed EGT. This step is only required for 1A24 and 1A23 rated engines. For all other ratings EGT trim is 0; move to the next step.
(6) Compare the actual N1 to the target N1 value and adjust the actual N2 and EGT value 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:
(7) Identify the adjustments for EGT and N2 as a function of N1 modifier level (for example, 2) from the table below. Add the fan speed (N1) modifier adjustments to the EGT and N2 values calculated in Step 4.B.(6) as follows:
N1 Modifier Adjustments
(a) EGT adjusted = 799 - 7= 792 deg.C (1457.6 deg.F).
Altitude Adjustment on Measurement
(9)
Limits Adjustment for Ratings
(b) Add the adjustments to the EGT and N2 values to find the limits for the engine rating.
(12) If the data is not in line with the limits, let the engine become stable at idle for four minutes and do the power assurance again at the same power level.
(13) If the data is still not in line with the limits after a second engine run, investigate the reported fault messages in the Troubleshooting Manual.
(14) If the cause is found and corrected, do the power assurance check again.
(15) If the engine exceeds the 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 used by itself as a primary reason for engine replacement.
(16) Stabilize the engine for ten minutes at idle.
(17) Stop the engines (Ref. AMM TASK 71-00-00-860-829).
(18) Do a visual inspection of the engine, the engine inlet and exhaust areas.
5. Close-up(1) Increase the tested engine speed to within plus or minus 0.5 percent of the N1 target that you find for 72.5 percent power. Let it become stable for four minutes to warm up the engine.
NOTE: Example: With the OAT at 25 deg.C (77.00 deg.F), the target N1 is 73.7 percent plus or minus 0.5 percent.
NOTE: If the engine exceeds the operational limits, do the inspection procedure (Ref. AMM TASK 72-00-00-200-818).
NOTE: If abnormal operation occurs, do the necessary abnormal or emergency procedure (Ref. AMM TASK 71-00-00-869-804).
(2) Slowly decrease the tested engine speed to minimum idle. Let it become stable for three minutes. Write down these parameters to aid in troubleshooting, if necessary: N1, N2 and EGT. (3) Increase the tested engine speed to within plus or minus 0.5 percent of the N1 target that you found for 72.5 percent power. Let it become stable for four minutes. Write down these parameters N1, N2, EGT, altitude and OAT or TAT.
(4) Slowly decrease the tested engine speed to minimum idle.
(5) Adjust the measured EGT for removal of EGT trim in cockpit displayed EGT. This step is only required for 1A24 and 1A23 rated engines. For all other ratings EGT trim is 0; move to the next step.
(6) Compare the actual N1 to the target N1 value and adjust the actual N2 and EGT value 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:
- N2: 0.03 percent
- EGT: 1 deg.C (1.8 deg.F).
NOTE: Example: Recorded N1 was 74 percent which is 0.3 percent above the target N1. The multiplying factor for the adjustments is 0.3/0.1 = 3. The N2 adjustment is 3 X 0.03 = 0.09 percent. The EGT adjustment is 3 X 1 = 3 deg.C (5.4 deg.F).
(b) If the actual N1 is more than the N1 target, subtract the adjustments from the actual N2 and EGT. NOTE: Example: Since the recorded N1 was more than the N1 target, you must subtract the adjustments as follows:
(c) If the actual N1 is less than the N1 target, add the adjustments to the actual N2 and EGT. - N2 adjusted = 100 - 0.1 = 99.9 percent
- EGT adjusted = 800 - 3 = 797 deg.C (1466.60 deg.F).
(7) Identify the adjustments for EGT and N2 as a function of N1 modifier level (for example, 2) from the table below. Add the fan speed (N1) modifier adjustments to the EGT and N2 values calculated in Step 4.B.(6) as follows:
N1 Modifier Adjustments
| N1 Modifier Level | EGT Degrees Celsius | N2 Percent |
|---|---|---|
| 0 | 0 | 0 |
| 1 | 1 | 0.0 |
| 2 | 2 | 0.1 |
| 3 | 4 | 0.1 |
| 4 | 5 | 0.2 |
| 5 | 6 | 0.2 |
| 6 | 7 | 0.2 |
| 7 | 8 | 0.3 |
NOTE: Example: For a level 2 N1 modifier, DEGT = +2 deg.C and N2= +0.1 percent as follows:
(8) Adjust the measured EGT to an equivalent sea-level trimmed EGT using the altitude at which the power assurance test was conducted. Using the ongoing example, the data were obtained at 1219.18 m (4000 ft.) above the sea level. Entering the Altitude Adjustment on Measurement table at 4000 ft., there is a -7 deg.C (-12.6 deg.F) adjustment. - EGT adjusted = 797 +2 = 799 deg.C (1470.2 deg.F)
- N2 adjusted = 99.9 +0.1 = 100.0 percent.
(a) EGT adjusted = 799 - 7= 792 deg.C (1457.6 deg.F).
Altitude Adjustment on Measurement
| Altitude (ft) | 0 | 2000 | 9000 | 12000 | 15000 |
|---|---|---|---|---|---|
| EGT deg.C adjustment | 0 | -7 | -7 | -11 | -13 |
NOTE: Example: At OAT or TAT of 25 deg.C (77.00 deg.F).
(a) Further adjustment of the limits is required if the engine is not at the A33 rating. The adjustments for the EGT and N2 values are obtained from the table below. - EGT MAX = 811 deg.C (1491.8 deg.F) and N2 MAX = 105.6 percent
- These limits are for a A33 rated engine.
NOTE: Example: The engine rating of interest is A32. The EGT adjustment is 11 degrees and the N2 adjustment is 0 percent.
Limits Adjustment for Ratings
| Rating | EGT Degrees Celsius | N2 Percent |
|---|---|---|
| 1A35A | 0 | 0 |
| 1A33 | 0 | 0 |
| 1A33B2 | 0 | 0 |
| 1A32 | 11 | 0 |
| 1A30 | 32 | 0 |
| 1A29 / 1A29CJ | 30 | 0 |
| 1A26 / 1A26CJ | 28 | 0 |
| 1A26E1 | 13 | 0 |
| 1A24 | 40 | 0 |
| 1A24E1 | 20 | 0 |
| 1A23 | 40 | 0 |
NOTE: Example: Limits for a A32.
(c) Comparison of the data collected - EGT MAX adjusted = 811 + 11 = 822 deg.C (1511.6 deg.F)
- N2 MAX adjusted = 105.6 + 0 = 105.6 percent.
CAUTION:
TAKEOFFS AT ALTITUDE MAY REQUIRE GREATER EGT MARGIN THAN AT SEA LEVEL.
1 Compare the data collected during the power assurance check to the limits. The margins calculated in this step will apply to sea level takeoffs. NOTE:
- EGT Margin (EGT MAX adjusted - EGT adjusted) = 822 - 792 = 30 deg.C (54 deg.F).
- N2 Margin (N2 MAX adjusted - N2 adjusted) = 105.6 - 100.0 = 5.6 percent.
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.
(10) Further adjust the EGT margin for the altitude effect. If the aircraft regularly operates at airports above sea level, an adjustment to the calculated EGT margin may be needed. The table shows altitude adjustments to sea level EGT margin for various ratings. 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. NOTE: Example: For an A32 engine at 4000 ft. (1219.18 m) above the sea level with 30 deg.C (54 deg.F) EGT margin at sea level: The adjustment at 4000 ft. (1219.18 m) is:
(11) If the adjusted values for the EGT and the N2 are less than the maximum limits (if the EGT and N2 margins 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. - EGT margin adjusted = ((-8 - 0) X (4000 - 2000) / (5000 - 2000)) + (0) = -5 deg.C (23 deg.F)
- EGT margin at 4000 feet = 30 - 11 = 19 deg.C (34.2 deg.F).
(12) If the data is not in line with the limits, let the engine become stable at idle for four minutes and do the power assurance again at the same power level.
(13) If the data is still not in line with the limits after a second engine run, investigate the reported fault messages in the Troubleshooting Manual.
(14) If the cause is found and corrected, do the power assurance check again.
(15) If the engine exceeds the 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 used by itself as a primary reason for engine replacement.
(16) Stabilize the engine for ten minutes at idle.
(17) Stop the engines (Ref. AMM TASK 71-00-00-860-829).
(18) Do a visual inspection of the engine, the engine inlet and exhaust areas.
Subtask 71-00-00-860-260-A
A. Put the aircraft back to its initial configuration.
(1) On the ELEC panel 35 VU:
(a) Push the GEN 1(2) pushbutton switch (the OFF legend goes off).
(2) On the AIR COND panel 30VU:
(a) Push the ENG 1(2) BLEED pushbutton switch (the OFF legend goes off).
(3) On the overhead panel 20VU, on the ADIRS CDU, set the three OFF/NAV/ATT selector switches to OFF.
Subtask 71-00-00-862-107-A (1) On the ELEC panel 35 VU:
(a) Push the GEN 1(2) pushbutton switch (the OFF legend goes off).
(2) On the AIR COND panel 30VU:
(a) Push the ENG 1(2) BLEED pushbutton switch (the OFF legend goes off).
(3) On the overhead panel 20VU, on the ADIRS CDU, set the three OFF/NAV/ATT selector switches to OFF.