Functional Check of the Pressure Relief Door Latch Tension [CFMB]

TASK 71-13-11-280-802-C
Functional Check of the Pressure Relief Door Latch Tension

1. Reason for the Job
Refer to the MPD TASK: 711000-C5
FUNCTIONAL CHECK OF PRESSURE RELIEF DOOR LATCH TENSION.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	WARNING NOTICE(S)
RSE1234	1	ADAPTER TORQUE TOOL

B. Referenced Information

REFERENCE	DESIGNATION
Pressure Relief Door

3. Job Set-up
Subtask 71-13-11-941-076-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).

Subtask 71-13-11-010-072-A

DELETED

4. Procedure
Subtask 71-13-11-280-052-A ** ON A/C NOT FOR ALL

A. Do a functional check of the pressure relief door as follows:
(1) Calculate the latch release load necessary to open the latch with the formula shown below:

P = (L + 1.5) x T / (0.53 x L) where:

P = Latch release load (in lbf or daN)
T = Torque value read on torque wrench when latch start to move (in lbf.in or m.daN)
L = Torque wrench effective length (in inch if T is indicated in lbf.in or in meter if T is indicated in m.daN).

NOTE: The torque wrench effective length is the distance between the point of application of force (where the hand is placed on the torque wrench handle) and the center line of the torque wrench 0.375 drive.

The latch release loads for the fan cowl pressure relief door must be between 98 lbf (43.59 daN) and 118 lbf (52.49 daN).
Example:

If the measured torque wrench effective length = 12 in. (L = 12)

If the read torque value = 46.2 lbf.in (T = 46.2)
Calculated as:

(12 + 1.5) x 46.2 623.7

------------------ = ------ = 98.06603

0.53 x 12 6.36

P = 98.06603 lbf

(2) Do the steps that follow:
(a) Install the RSE1234 ADAPTER TORQUE TOOL on the torque wrench.
(b) Put the torque wrench in the latch release slot.
(c) Measure the effective length (L) of the torque wrench handle and put the hand at that position. Hold the handle with the thumb and the forefinger.
(d) Slowly apply force to the torque wrench. Make sure that the force is applied at a 90 degree angle to the torque wrench handle.
(e) When the latch starts to move write down the torque value (T) shown on the torque wrench.
(f) Calculate the latch release load (P) with the formula shown in step (1).
(g) If the calculated load is below or above the limits 98 lbf (43.59 daN) and 118 lbf (52.49 daN), replace the door latch.

5. Close-up
Subtask 71-13-11-410-067-A ** ON A/C NOT FOR ALL

A. Close Access
(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] 2026.04.02 06:32:17 UTC