Power Assurance Check [CFMB]

TASK 71-00-00-710-008-B
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 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:

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.
Do not use the power assurance check as the only cause for engine replacement.

NOTE: The examples shown in this procedure are for these test conditions:

OAT = 25 deg. C
N1 modifier for this engine = 2
72.5 percent power setting
altitude 4000 feet.

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-B	Engine Automatic Start
TASK 71-00-00-710-028-B	Engine Shutdown
TASK 71-00-00-869-001-B	Abnormal Operation and Emergency Procedures
TASK 71-00-00-869-003-A	Wind Limitations During Engine Ground Operations
TASK 71-00-00-869-004-A	Safety Precautions During Engine Ground Operations
TASK 72-00-00-200-008-A	Inspection/Check After the Engine has Exceeded the Operational Limits
Tool Installation
Results Sheet
72.5 Percent Power Assurance Setting

3. Job Set-up
Subtask 71-00-00-861-063-A ** ON A/C NOT FOR ALL

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

Subtask 71-00-00-865-104-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 71-00-00-869-104-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 71-00-00-869-003) and (Ref. AMM TASK 71-00-00-869-004).

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 6614 lb (3000 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 the 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.
(8) Examine the general condition of the fan spinner and fan blades, core exhaust nozzle, Low Pressure Turbne (LPT) and external surfaces of the cowls.
(9) Examine the 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 Outside Air Temperature (OAT).
EXAMPLE: OAT = 25 deg. C
(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 71-00-00-869-104-C ** ON A/C NOT FOR ALL

C. Preparation for Test

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: - 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:

(1) Obey the wind limitations and safety precautions during engine ground operation (Ref. AMM TASK 71-00-00-869-003) and (Ref. AMM TASK 71-00-00-869-004).

(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 6614 lb (3000 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 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.
(8) Examine the general condition of the fan spinner and fan blades, core exhaust nozzle, Low Pressure Turbne (LPT) and external surfaces of the cowls.
(9) Examine the 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 Outside Air Temperature (OAT).
EXAMPLE: OAT = 25 deg. C
(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 MSU panel 41VU, 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 71-00-00-869-105-A ** ON A/C NOT FOR ALL

D. Find the N1 target values for the temperature that you measured.

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

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 PFD altimeter.
EXAMPLE: Altitude = 4000 feet

Subtask 71-00-00-710-081-A ** ON A/C NOT FOR ALL

E. Start the two engines and let them become stable at minimum idle for 2 minutes minimum (Ref. AMM TASK 71-00-00-710-003).

4. Procedure
Subtask 71-00-00-710-190-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 N1.

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 landing gear control and indicating panel 402VU:
(a) Make sure that A/SKID & N/W STRG selector switch 5GG is set to ON.
(3) On RUD TRIM/PARKING BRK panel 110VU:
(a) 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 RUD TRIM/PARKING BRK panel 110VU:
(a) Set the PARKING BRAKE control switch to OFF position.
(6) Perform the the power assurance check per step 4.B.
(7) After test completion, put the aircraft in the "parking brake applied" configuration:
(a) On the center pedestal, on RUD TRIM/PARKING BRK panel 110VU:

Set the PARKING BRAKE control switch to ON position.

(b) Release the brake pedals.

Subtask 71-00-00-710-190-B ** 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 N1.

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 A/SKID & N/W STRG selector switch 5GG is set to ON.
(3) On RUD TRIM/PARKING BRK panel 110VU:
(a) 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) Perform the the power assurance check per step 4.B.
(6) After test completion, release the brake pedals to put the aircraft in the "parking-brake applied" configuration.

Subtask 71-00-00-710-169-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 72.5 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 73.7 percent plus or minus 0.5 percent.

NOTE: If the engine exceeds the operational limits, do the inspection procedure (Ref. AMM TASK 72-00-00-200-008).

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

(2) Decrease the tested engine speed to 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 72.5 percent power. Let it become stable for 4 minutes. Write down these parameters N1, N2, EGT altitude and OAT or TAT.
EXAMPLE: Recorded values: N1 = 74 percent, N2 = 94.0 percent, EGT = 688 deg.C.
(4) Slowly decrease the engine speed to minimum idle.
(5) 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:

N2..........0.04 percent
EGT.........1 deg.C
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 0.04 = 0.12 percent. The EGT adjustment is 3 X 1 = 3 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 as follows:

N2 adj. = 94 - 0.12 = 93.88 percent
EGT adj. = 688 - 3 = 685 deg.C

(c) If actual N1 is less than the N1 target, add the adjustments to the actual N2 and EGT.
(6) Identify adjustments for EGT and N2 as a function of engine rating (for example, 5B6) and N1 modifier level (for example, 2) from the table below. Subtract fan speed (N1) modifier adjustments from the EGT and N2 values calculated in step 4. B. (5) as follows:

N1 Modifier Adjustments
Rating 5B1/2/3

-------------------------------------------------------------------------------

! N1 MODIFIER LEVEL ! EGT DEG.C ! N2 PERCENT !

-------------------------------------------------------------------------------

! 0 ! 0 ! 0 !

!-----------------------!------------------------!----------------------------!

! 1 ! 2 ! 0.1 !

!-----------------------!------------------------!----------------------------!

! 2 ! 5 ! 0.1 !

!-----------------------!------------------------!----------------------------!

! 3 ! 7 ! 0.2 !

!-----------------------!------------------------!----------------------------!

! 4 ! 10 ! 0.3 !

!-----------------------!------------------------!----------------------------!

! 5 ! 12 ! 0.4 !

!-----------------------!------------------------!----------------------------!

! 6 ! 16 ! 0.5 !

!-----------------------!------------------------!----------------------------!

! 7 ! 20 ! 0.6 !

-------------------------------------------------------------------------------

Rating 5B4/5/6/7/8/9

-------------------------------------------------------------------------------

! N1 MODIFIER LEVEL ! EGT DEG.C ! N2 PERCENT !

-------------------------------------------------------------------------------

! 0 ! 0 ! 0 !

!-----------------------!------------------------!----------------------------!

! 1 ! 1 ! 0.1 !

!-----------------------!------------------------!----------------------------!

! 2 ! 3 ! 0.1 !

!-----------------------!------------------------!----------------------------!

! 3 ! 5 ! 0.2 !

!-----------------------!------------------------!----------------------------!

! 4 ! 6 ! 0.2 !

!-----------------------!------------------------!----------------------------!

! 5 ! 8 ! 0.3 !

!-----------------------!------------------------!----------------------------!

! 6 ! 10 ! 0.4 !

!-----------------------!------------------------!----------------------------!

! 7 ! 13 ! 0.5 !

-------------------------------------------------------------------------------

EXAMPLE: For a level 2 N1 modifier at the 5B6 rating, DEGT = 3 deg.C and N2 = 0.1 percent as follows:

EGT adjusted = 685 - 3 = 682 deg.C
N2 adj. = 93.88 - 0.1 = 93.78 percent

(7) Adjust measured EGT to equivalent sea-level trimmed EGT using the altitude at which the power assurance test was conducted and the engine rating. Using the 5B6 example from above, suppose the data were obtained at Calgary, Alberta, Canada at 3740 ft. (1139.93 m) above sea level. Entering the table at the 5B6 rating, there is a 5 deg.C (41.00 deg.F) adjustment for 2000 ft. (609.59 m) and a 21 deg.C (69.80 deg.F) adjustment for 5000 ft. (1523.97 m). The adjustment for 3740 ft. (1139.93 m) is:

DEGT = 5 + (21 - 5) X (3740 - 2000)/(5000 - 2000) = 14.3 deg.C (57.74 deg.F)
EGT adjusted = 682 + 14.3 = 696 deg.C (1284.8 deg.F)

CFM56-5B EGT Trim Adjustment

-------------------------------------------------

! Rating/ALT ! 0 ! 2000 ! 5000 ! 12000 !

!--------------!-------!-------!-------!--------!

! B1 ! 0 ! 0 ! 0 ! 0 !

!--------------!-------!-------!-------!--------!

! B2 ! 0 ! 0 ! 0 ! 0 !

!--------------!-------!-------!-------!--------!

! B3 ! 0 ! 0 ! 0 ! 0 !

!--------------!-------!-------!-------!--------!

! B4 & B7 ! 0 ! 0 ! 0 ! 0 !

!--------------!-------!-------!-------!--------!

! B5 ! 0 ! 2 ! 16 ! 23 !

!--------------!-------!-------!-------!--------!

! B6 ! 0 ! 5 ! 21 ! 30 !

!--------------!-------!-------!-------!--------!

! B8 ! 0 ! 1 ! 3 ! 8 !

!--------------!-------!-------!-------!--------!

! B9 ! 0 ! 7 ! 25 ! 34 !

! ! ! ! ! !

-------------------------------------------------

(8) Compare the data collected during the power assurance check to the permitted limits.

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

EXAMPLE: Enter Ref. Fig. at OAT or TAT of 25 deg.C

EGT MAX = 654 deg.C and N2 MAX = 94.2 percent.
These limits are for a CFM56-5B3 rated engine.

(a) Further adjustment of the limits is required if the engine is not at the 5B3 rating. The adjustments for EGT and N2 are obtained from the table below.
EXAMPLE: The engine rating of interest is the CFM56-5B6. The EGT adjustment is 72 degrees and the N2 adjustment is 0.5 percent.

CFM56-5B Rating Conversion at 72.5 Percent Power

-------------------------------------------------------------------------------

! Conversion to ! EGT DEG.C ! N2 PERCENT !

-------------------------------------------------------------------------------

! - ! - ! - !

!------------------------!-------------------------!--------------------------!

! B1 ! 45 ! 0.5 !

!------------------------!-------------------------!--------------------------!

! B2 ! 29 ! 0.0 !

!------------------------!-------------------------!--------------------------!

! B3 ! 0 ! 0.0 !

!------------------------!-------------------------!--------------------------!

! B4 & B7 ! 40 ! 0.2 !

!------------------------!-------------------------!--------------------------!

! B5 ! 91 ! 0.6 !

!------------------------!-------------------------!--------------------------!

! B6 ! 72 ! 0.5 !

!------------------------!-------------------------!--------------------------!

! B8 ! 108 ! 0.7 !

!------------------------!-------------------------!--------------------------!

! B9 ! 75 ! 0.0 !

-------------------------------------------------------------------------------

(b) Add the adjustments to EGT and N2 to find the limits for the engine rating.
EXAMPLE: Limits for a CFM56-5B6 engine.

EGT MAX adjusted = 654 + 72 = 726 deg.C
N2 MAX adj. = 94.2 + 0.5 = 94.7 percent

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

(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 = 726.0 deg C and N2 MAX = 95.4 percent

EGT Margin (EGT MAX adj - EGT adj) = 726 - 696 = 30 deg.C
N2 Margin (N2 MAX adj - N2 adj) = 94.7 - 93.8 = 0.9 percent

(9) Further adjust the EGT margin for altitude effect. If the aircraft regularly operates at airports above 3000 feet, 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 B1, B2 or B3 ratings is necessary since altitude EGT margin is equal to or greater than sea level EGT margin. 5B4 and 5B7 ratings may 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.

-------------------------------------------------------------------------------

! Flight Condition ! ! Adjustments !

! Rating ! Altitude ft ! dEGT deg.C !

-------------------------------------------------------------------------------

! B1 ! 0 to 8k ! 0 !

!------------------------!-----------------------!----------------------------!

! B1 ! 10k ! 10 !

!------------------------!-----------------------!----------------------------!

! B2 ! 0 to 8k ! 0 !

!------------------------!-----------------------!----------------------------!

! B2 ! 10k ! 10 !

!------------------------!-----------------------!----------------------------!

! B3 ! 0 to 3k ! 0 !

!------------------------!-----------------------!----------------------------!

! B3 ! 10k ! 26 !

!------------------------!-----------------------!----------------------------!

! B4 & B7 ! 0 to 4k ! 0 !

!------------------------!-----------------------!----------------------------!

! B4 & B7 ! 6k to 8k ! -14 !

!------------------------!-----------------------!----------------------------!

! B4 & B7 ! 12k ! 11 !

!------------------------!-----------------------!----------------------------!

! B5 ! 0 to 12k ! 0 !

!------------------------!-----------------------!----------------------------!

! B6 ! 0 to 12k ! 0 !

!------------------------!-----------------------!----------------------------!

! B8 ! 0 to 12k ! 0 !

!------------------------!-----------------------!----------------------------!

! B9 ! 0 to 12k ! 0 !

-------------------------------------------------------------------------------

EXAMPLE: For a 5B4 engine at 5000 ft. (1523.97 m) above sea level with 44 deg.C (111.20 deg.F) EGT margin at sea level: The 5B4 EGT margin is constant up to 4000 ft. (1219.18 m) above sea level and is lower by 14 deg.C (57.20 deg.F) at 6000 ft. (1828.77 m) according to the table. Using interpolation, the adjustment at 5000 ft. (1523.97 m) is:

EGT marg adj = (-14) X (5000-4000)/(6000-4000) + (0) = -7.0 deg.C (-44.6 deg.F)
EGT margin at 5000 feet = 44 - 7 = 37 deg.C (98.6 deg.F)

(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 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 the 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 used by itself as a primary reason for engine replacement.
(10) Stop the engines (Ref. AMM TASK 71-00-00-710-028).
(11) Do a visual inspection of the engine, the engine inlet and exhaust areas.

5. Close-up
Subtask 71-00-00-869-106-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 71-00-00-862-063-A ** ON A/C NOT FOR ALL

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

[Rev.10 from 2021] 2026.04.01 02:24:44 UTC