Functional Check of Fan Cowl Latch Tension [PW11]

TASK 71-13-11-720-801-A
Functional Check of Fan Cowl Latch Tension

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURY CAN OCCUR.

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

WARNING: WEAR APPLICABLE PERSONAL PROTECTIVE EQUIPMENT (PPE) WHEN YOU DO THIS TASK. BEFORE YOU USE PPE, READ, UNDERSTAND AND OBEY ALL INSTRUCTIONS FOR ITS USE. THESE INSTRUCTIONS INCLUDE INSTRUCTIONS FROM THE MANUFACTURER, YOUR EMPLOYER AND GOVERNMENT REGULATIONS. YOU CAN GET INJURED IF YOU DO NOT USE PPE. GET INSTRUCTIONS FROM YOUR EMPLOYER ON WHICH PPE IS NECESSARY.

ZONE: 400

1. Reason for the Job
Refer to the MPD TASK: 711000-W1
FUNCTIONAL CHECK OF FAN COWL LATCH TENSION.

NOTE: The effectivity of this task is "ALL". To know if this task is applicable to your aircraft, refer to the MPD task applicability.

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

REFERENCE	QTY	DESIGNATION
No specific	1	AIR SOURCE - REGULATED, FILTERED, DRY
No specific	1	GAGE - FEELER
No specific	1	GAGE 45 DAN (100 LBF) - PUSH-PULL
No specific	1	VERNIER CALIPER
No specific	Torque wrench: range to between 70 and 60 lbf.in (0.79 and 0.68 m.daN )
No specific	Torque wrench: range to between 270 and 240 lbf.in (3.05 and 2.71 m.daN )

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.PU1-0001)	lint-free cotton cloth
(Material No.PU2-0001)	alcohol, isopropyl
(Material No.PU4-0002)	epoxy primer, fluid resistant
(Material No.PU4-0004)	curing solution, epoxy primer
(Material No.PU4-0005)	thinner

C. Work Zones and Access Panels

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

D. Referenced Information

REFERENCE	DESIGNATION
TASK 70-30-00-918-803-A	Consumable Materials Index for the Nacelle (UTC Aerospace Systems)
TASK 71-00-00-860-833-A	Procedure to Prevent Engine Motoring
TASK 78-36-00-410-802-A	Closing of the Thrust Reverser Cowl-Doors
The Fan Cowl Latch Tension
Fan Cowl Aft Latch

3. Job Set-up
Subtask 71-13-11-941-083-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) Do the procedure to prevent engine motoring
(Ref. AMM TASK 71-00-00-860-833).
(2) Make sure the thrust reverser is latched (Ref. AMM TASK 78-36-00-410-802).

4. Procedure
Subtask 71-13-11-140-050-A ** ON A/C NOT FOR ALL

WARNING: USE A PROTECTIVE EYE SHIELD OR GOGGLES WHEN YOU USE COMPRESSED AIR. IF YOU GET HIGH-PRESSURE AIR OR PARTICLES IN YOUR EYES, IN YOUR MOUTH OR ON YOUR SKIN, INJURY CAN OCCUR.

CAUTION: WHEN YOU OPEN OR CLOSE THE FAN COWL AFT LATCH (L3), OBEY THESE INSTRUCTIONS:

DO NOT OPEN THE LATCH HOOK MORE THAN NECESSARY TO DISENGAGE FROM OR ENGAGE THE KEEPER.
DO NOT MOVE THE LATCH HOOK TOO MUCH IN THE DIRECTION OF THE LATCH HANDLE OR PUT THE LATCH HOOK AGAINST THE LATCH HANDLE.
MAKE SURE THAT THE ANGULAR POSITION OF THE LATCH HOOK IS A MINIMUM OF 90 DEGREES FROM THE LATCH HANDLE.

IF YOU DO NOT OBEY THESE INSTRUCTIONS, THE LATCH CAN HIT THE ENGINE OIL TUBE AND CAUSE DAMAGE.

A. Cleaning of the Latches

Fan Cowl Aft Latch ** ON A/C NOT FOR ALL

CAUTION: IF THERE IS SAND AND/OR DUST ON THE LATCHES, REMOVE THE CONTAMINATION WITH DRY, COMPRESSED AIR BEFORE YOU ADJUST THE LATCHES. SAND AND DUST IN THE LATCHES CAN CAUSE DAMAGE.

(1) If necessary, use an AIR SOURCE - REGULATED, FILTERED, DRY to remove the sand and dust particles from the latches.

Subtask 71-13-11-720-051-A ** ON A/C NOT FOR ALL

B. Measurement of the Gaps and Closing Force of the Latches
(1) If necessary, close the forward (L1), the aft (L3) and the center (L2) latches in that sequence.
(2) Measure the clearance between the alignment pins (1) and the related bushings on the opposite fan cowl door with the GAGE - FEELER or VERNIER CALIPER. Make sure that the clearance is not greater than 0.016 in. (0.41 mm). If the clearance is greater than 0.016 in. (0.41 mm), record the clearance and do the following:
(a) Remove the alignment pin (1) and the related washers (3) and (4) and nut (5) from the right fan cowl door.
(b) Clean the alignment pin (1), nut (5), and washers (3) and (4) with the clean lint-free cotton cloth (Material No.PU1-0001) made moist with the PU2-0001alcohol, isopropyl. Clean the mating surfaces of the keeper with the clean lint-free cotton cloth (Material No.PU1-0001) made moist with the PU2-0001alcohol, isopropyl. Remove the PU2-0001alcohol, isopropyl with the clean, dry lint-free cotton cloth (Material No.PU1-0001) before it dries.
(c) Mix the PU4-0002epoxy primer, fluid resistant or equivalent (Ref. AMM TASK 70-30-00-918-803), PU4-0004curing solution, epoxy primer and thinner (Material No.PU4-0005) . Refer to the instructions of the manufacturer.
(d) Put a mixture of the washers (3) and (4) together so that they make the same depth as the clearance you recorded for that alignment pin (1) in step 4.B.(2). Put these washers adjacent to the alignment pin (1). Put the remaining washers adjacent to the nut (5) to keep the correct grip length.

NOTE: There are two different types of washers. The washer (4) has a thickness of 0.016 in. (0.41 mm) and the washer (3) has a thickness of 0.032 in. (0.81 mm).

1 Use the washers and also turn the star wheel on the latch to get the correct clearance.
(e) Apply a layer of the PU4-0002epoxy primer, fluid resistant or equivalent (Ref. AMM TASK 70-30-00-918-803) mixture to the mating surface of the washers (3) and (4) that will touch the keeper. Apply a layer of the PU4-0002epoxy primer, fluid resistant or equivalent (Ref. AMM TASK 70-30-00-918-803) mixture to the shaft of the alignment pin (1) and to the mating surfaces of the keeper. Make sure that the mixture on the keeper is on an area that is larger than the washers (3) and (4) and the base of the alignment pin (1).
(f) Install the alignment pin (1), washers (3) and (4) and nut (5) on the right fan cowl door.
(g) TORQUE the nut (5) to between 270 and 240 lbf.in (3.05 and 2.71 m.daN )

.
(h) Do step 4.B.(2) again.
(3) Measure the clearance between the strikers (2) and the related washers on the opposite fan cowl door with the GAGE - FEELER or VERNIER CALIPER. Make sure that the clearance is not greater than 0.016 in. (0.41 mm). If the clearance is greater than 0.016 in. (0.41 mm), record the clearance and do the following:
(a) Remove the striker (2) and the related bolt (6), washers (7) and (8) and nut (9) from the right fan cowl door.
(b) Remove the opposite striker (2) and the related bolt (6), washers (7) and (8), and nut (9) from the left fan cowl door.
(c) Clean the strikers (2), bolts (6), washers (7) and (8), and nuts (9) with the clean lint-free cotton cloth (Material No.PU1-0001) made moist with the PU2-0001alcohol, isopropyl.
(d) Clean the mating surfaces of the keeper and latch housing with the clean lint-free cotton cloth (Material No.PU1-0001) made moist with the PU2-0001alcohol, isopropyl. Remove the PU2-0001alcohol, isopropyl with the clean, dry lint-free cotton cloth (Material No.PU1-0001) before it dries.
(e) Put a mixture of the washers (7) and (8) together so that they make the same depth as the clearance you recorded for that striker (2) in step 4.B.(3).
1 Put these washers adjacent to the striker (2).
2 Put the remaining washers adjacent to the nut (9) to keep the correct grip length.
3 Make sure that the thickness of the washers (7) and (8) adjacent to the strikers (2) are approximately the same on right and left fan cowl doors.

NOTE: There are two different types of washers. Washer (7) has a thickness of 0.026 in. (0.66 mm) - 0.034 in. (0.86 mm) and washer (8) has a thickness of 0.022 in. (0.56 mm) - 0.028 in. (0.71 mm).

a Use the washers and also turn the star wheel on the latch to get the correct clearance.
(f) Apply a layer of the PU4-0002epoxy primer, fluid resistant or equivalent (Ref. AMM TASK 70-30-00-918-803) mixture to the mating surface of the washers (7) and (8) that will touch the keeper. Apply a layer of the PU4-0002epoxy primer, fluid resistant or equivalent (Ref. AMM TASK 70-30-00-918-803) mixture to the shafts of the bolts (6) and to the mating surfaces of the keeper and latch housing. Make sure that the mixture on the keeper and latch housing is on an area that is larger than the washers (7) and (8).
(g) Install the striker (2), bolt (6), washers (7) and (8) and nut (9) on the right fan cowl door.
1 TORQUE the nut (9) to between 70 and 60 lbf.in (0.79 and 0.68 m.daN )

.
(h) Install the striker (2), bolt (6), washers (7) and (8) and nut (9) on the left fan cowl door.
1 TORQUE the nut (9) to between 70 and 60 lbf.in (0.79 and 0.68 m.daN )

.
(4) Measure the closing force of the forward latch (L1).
(a) Open the forward latch (L1).
(b) Measure the force necessary to close the forward latch (L1) with the GAGE 45 DAN (100 LBF) - PUSH-PULL located 0.5 in. (12.70 mm) from the edge of the latch handle. Make sure that the force necessary to close the latch is between 26 lbf (11.57 daN) and 36 lbf (16.01 daN).
(c) If the force is not correct, open the forward latch (L1) and disconnect the hook from the keeper. Turn the star wheel on the latch to increase or decrease the force to close the latch. Do step 4.B.(4)(b) again.
(d) Close the forward latch (L1).
(5) Measure the closing force of the aft latch (L3).
(a) Open the aft latch (L3).
(b) Measure the force necessary to close the aft latch (L3) with the GAGE 45 DAN (100 LBF) - PUSH-PULL located 0.5 in. (12.70 mm) from the edge of the latch handle. Make sure that the force necessary to close the latch is between 26 lbf (11.57 daN) and 36 lbf (16.01 daN).
(c) If the force is not correct, open the aft latch (L3) and disconnect the hook from the keeper. Turn the star wheel on the latch to increase or decrease the force to close the latch. Do step 4.B.(5)(b) again.
(d) Close the aft latch (L3).
(6) Measure the closing force of the center latch (L2).
(a) Open the center latch (L2).
(b) Measure the force necessary to close the center latch (L2) with the GAGE 45 DAN (100 LBF) - PUSH-PULL located 0.5 in. (12.70 mm) from the edge of the latch handle. Make sure that the force necessary to close the latch is between 26 lbf (11.57 daN) and 36 lbf (16.01 daN).
(c) If the force is not correct, open the center latch (L2) and disconnect the hook from the keeper. Turn the star wheel on the latch to increase or decrease the force to close the latch. Do step 4.B.(6)(b) again.
(d) Close the center latch (L2).
(7) Do step 4.B.(2) and step 4.B.(3) again to make sure that the clearances are correct. If the clearances are not correct, do step 4.B.(1) thru step 4.B.(7) again.

5. Close-up
Subtask 71-13-11-942-061-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 12:57:25 UTC