DOC AIRBUS | AMM A320FPWA 318 - Key Washer (Tab-Type) Installation [PW11]
TASK 70-24-00-910-807-A
PWA 318 - Key Washer (Tab-Type) Installation
This procedure gives general instructions for the installation of tab-type key washers.
A. Consumable Materials
B. Referenced Information
3. Job Set-up
Subtask 70-24-00-860-059-A ** ON A/C NOT FOR ALL
Subtask 70-24-00-910-059-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.02 07:29:07 UTC
PWA 318 - Key Washer (Tab-Type) Installation
WARNING:
BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.
1. Reason for the JobThis procedure gives general instructions for the installation of tab-type key washers.
NOTE: Always obey the specific procedures and limits in the specific maintenance manual tasks.
2. Job Set-up InformationA. Consumable Materials
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.P05-018) | Silver Pencil |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 70-40-00-910-801-A | Marking of Parts |
Installation of Key Washers - (Tab-Type)Subtask 70-24-00-860-059-A ** ON A/C NOT FOR ALL
A. Not Applicable
4. ProcedureSubtask 70-24-00-910-059-A ** ON A/C NOT FOR ALL
A. Installation of Key Washers (Tab-Type)
(1) General instructions
(a) Some key washers are pre-bent at manufacture.
(b) Use key washers only one time. Use a new key washer for each installation.
(c) Use the correct key washers as specified by the specific maintenance task.
(2) Install key washers as follows:
(a) Install the key washer so that the unbent keys are as far as possible from the axis of the part to be locked.
(b) The pre-bent key (Key B) must be tight to the overhanging surface as shown, or put against the side of the hole to prevent possible movement of the locked part.
(c) When you torque the fastener and bend the key washer, you must keep the key washer in the same position.
(d) If necessary, use a Silver Pencil (Material No.P05-018) or any marker as specified in Marking Parts (Ref. AMM TASK 70-40-00-910-801). Mark the parts so that you can detect any turn of the key washer during the torque of the nut.
(e) Hold the key washer against the anti-rotation surface in the loosening direction while you torque the fastener to the torque specified by the AMM task.
(f) Examine the pre-bent key (Key B) to make sure that it is not damaged.
(g) For pre-bent keys (Key B) that use a surface edge for anti-rotation, make sure that the gap between the key (Key B) and the surface is 0.020 in. (0.51 mm) or less.
1 You can bend the pre-bent key (Key B) at installation to meet the gap limits.
(h) Carefully bend all keys (Keys A) on the key washer so that it cannot be used again and that you do not cause cracks, gouges or other damage.
(i) Bend at least one key (Key A) so that 75 percent or more of its width (as measured at the base of the key) engages the flat of the fastener (Dimension A).
(j) Bend all the keys (Keys A) so that the gap is in the limits that follow:
1 For fastener threads 0.3125 in. (7.94 mm) or less, Gap A is 0.010 in. (0.25 mm) or less.
2 For fastener threads more than 0.3125 in. (7.94 mm), Gap A is 0.020 in. (0.51 mm) or less.
(3) Install elliptical key washers as follows:
(a) After you torque the fasteners, bend the washer up across one whole face of the hexagon.
1 For fastener threads 0.3125 in. (7.94 mm) or less, Gap A is 0.010 in. (0.25 mm) or less.
2 For fastener threads more than 0.3125 in. (7.94 mm), Gap A is 0.020 in. (0.51 mm) or less.
(4) The previous requirements for key washers and elliptical key washers are applicable to the keys for each hole in a multiple-hole key washer.
(5) Key washers used with fuel nozzle nuts must not have the keys bent by impact.
(6) Examine the installed key washer as follows:
(a) Make sure that a new key washer was installed.
(b) Make sure that the keys are bent as previously specified.
(c) Make sure that the keys are bent so that the key washer and fastener cannot move or turn to loosen.
(d) Scoring, gouging and smearing of the key washer or adjacent parts are not permitted.
(e) Small tool marks from usual forming and bending procedures are permitted.
Subtask 70-24-00-910-060-A ** ON A/C NOT FOR ALL (1) General instructions
(a) Some key washers are pre-bent at manufacture.
(b) Use key washers only one time. Use a new key washer for each installation.
(c) Use the correct key washers as specified by the specific maintenance task.
(2) Install key washers as follows:
(a) Install the key washer so that the unbent keys are as far as possible from the axis of the part to be locked.
(b) The pre-bent key (Key B) must be tight to the overhanging surface as shown, or put against the side of the hole to prevent possible movement of the locked part.
(c) When you torque the fastener and bend the key washer, you must keep the key washer in the same position.
(d) If necessary, use a Silver Pencil (Material No.P05-018) or any marker as specified in Marking Parts (Ref. AMM TASK 70-40-00-910-801). Mark the parts so that you can detect any turn of the key washer during the torque of the nut.
(e) Hold the key washer against the anti-rotation surface in the loosening direction while you torque the fastener to the torque specified by the AMM task.
(f) Examine the pre-bent key (Key B) to make sure that it is not damaged.
(g) For pre-bent keys (Key B) that use a surface edge for anti-rotation, make sure that the gap between the key (Key B) and the surface is 0.020 in. (0.51 mm) or less.
1 You can bend the pre-bent key (Key B) at installation to meet the gap limits.
(h) Carefully bend all keys (Keys A) on the key washer so that it cannot be used again and that you do not cause cracks, gouges or other damage.
(i) Bend at least one key (Key A) so that 75 percent or more of its width (as measured at the base of the key) engages the flat of the fastener (Dimension A).
(j) Bend all the keys (Keys A) so that the gap is in the limits that follow:
1 For fastener threads 0.3125 in. (7.94 mm) or less, Gap A is 0.010 in. (0.25 mm) or less.
2 For fastener threads more than 0.3125 in. (7.94 mm), Gap A is 0.020 in. (0.51 mm) or less.
(3) Install elliptical key washers as follows:
(a) After you torque the fasteners, bend the washer up across one whole face of the hexagon.
1 For fastener threads 0.3125 in. (7.94 mm) or less, Gap A is 0.010 in. (0.25 mm) or less.
2 For fastener threads more than 0.3125 in. (7.94 mm), Gap A is 0.020 in. (0.51 mm) or less.
(4) The previous requirements for key washers and elliptical key washers are applicable to the keys for each hole in a multiple-hole key washer.
(5) Key washers used with fuel nozzle nuts must not have the keys bent by impact.
(6) Examine the installed key washer as follows:
(a) Make sure that a new key washer was installed.
(b) Make sure that the keys are bent as previously specified.
(c) Make sure that the keys are bent so that the key washer and fastener cannot move or turn to loosen.
(d) Scoring, gouging and smearing of the key washer or adjacent parts are not permitted.
(e) Small tool marks from usual forming and bending procedures are permitted.
B. Installation of Key Washers (Cup-Type)
(1) General instructions
(a) Always obey the specific procedures and limits in the specific maintenance tasks.
(b) Some key washers are pre-bent at manufacture.
(c) Use key washers only one time. Use a new key washer for each installation.
(d) Use the correct key washers as specified by the specific AMM maintenance task.
(e) Crimping tools
1 Tool requirements
a The portion of the tool that forms the indentations must be spherically shaped and have a spherical radius of not less than 0.050 in. (1.27 mm).
2 Squeeze action tool
a This tool forms indentations by pressing the cup-type key washer into slots in the nut or bolt. This type of tool is recommended and must be used where possible.
3 Drift type tool
a This tool consists of a ring with prongs on the inside diameter. This tool, when put over the cup-type key washer and moved in an axial direction, will form indentations on the outside diameter of the cup-type key washer.
4 Punch
(2) Install the key washers as follows:
(a) Marking
2 Use a Silver Pencil (Material No.P05-018) or any marker as specified in Marking Parts (Ref. AMM TASK 70-40-00-910-801). Mark the parts so that you can detect any turn of the key washer during the torque of the nut.
(b) Required number of indentations
1 For the cup-type key washers, you must bend the key washer in two or more places to give sufficient interference with the nut so that the nut will not turn. Refer to
and
for requirements.
2 After you tighten and torque the nut, you must indent the cup-type key washer in the correct number of places. Refer to Table 1 unless specified differently.
3 If the number of rounded slots in the nut or bolt is less than the necessary amount of indentations, the requirements of Table 1 do not apply.
4 If the key washer is the type shown in
, the requirements of Table 1 do not apply.
a Table 1 - Required Number of Indentations
(*) See
for indentation spacing.
5 For the cup-type key washers shown in
and
, you must make the indentations as shown.
(c) Key washer engagement
1 Table 2 - Required Engagement Measurements for Cup-Type Key Washers
(d) Examine the installed key washer as follows:
1 Make sure that a new key washer was installed.
2 Make sure that the key washer is not loose and cannot shake or rattle.
3 Make sure that the cup is bent as previously specified.
4 Make sure that the key washer did not move during the assembly.
5 If there is no axial pinch on the diaphragm portion of the key washer, you can move the washer with your hand through the limits of the tab clearance.
6 Cracking, tearing, scoring, gouging and smearing of the key washer or adjacent parts are not permitted.
7 Small tool marks from usual forming and bending procedures are permitted.
8 Indentations in one key washer must be of similar size and shape.
9 Indentations in the key washer must be formed into the rounded slots in the nut where the nut has such slots.
(1) General instructions
(a) Always obey the specific procedures and limits in the specific maintenance tasks.
(b) Some key washers are pre-bent at manufacture.
(c) Use key washers only one time. Use a new key washer for each installation.
(d) Use the correct key washers as specified by the specific AMM maintenance task.
(e) Crimping tools
1 Tool requirements
a The portion of the tool that forms the indentations must be spherically shaped and have a spherical radius of not less than 0.050 in. (1.27 mm).
2 Squeeze action tool
a This tool forms indentations by pressing the cup-type key washer into slots in the nut or bolt. This type of tool is recommended and must be used where possible.
3 Drift type tool
a This tool consists of a ring with prongs on the inside diameter. This tool, when put over the cup-type key washer and moved in an axial direction, will form indentations on the outside diameter of the cup-type key washer.
4 Punch
CAUTION:
DO NOT USE A "PUNCH" TYPE TOOL TO INSTALL CUP-TYPE KEY WASHERS ON FUEL NOZZLE NUTS. CUP-TYPE KEY WASHERS USED WITH FUEL NOZZLE NUTS MUST NOT HAVE THE INDENTATIONS FORMED BY IMPACT. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE FUEL NOZZLE CAN OCCUR.
a This tool will form indentations on the outside diameter of the cup-type key washer by the impact of the tool with a hammer. (2) Install the key washers as follows:
(a) Marking
CAUTION:
USE THE CORRECT MARKING PEN OR PENCIL. IF YOU DO NOT, THE MARK CAN CAUSE DAMAGE TO THE MATERIALS.
1 To prevent broken or bent key washer tabs, you must mark the position of the cup-type key washer to the adjacent surface before you tighten and torque the nut. 2 Use a Silver Pencil (Material No.P05-018) or any marker as specified in Marking Parts (Ref. AMM TASK 70-40-00-910-801). Mark the parts so that you can detect any turn of the key washer during the torque of the nut.
(b) Required number of indentations
1 For the cup-type key washers, you must bend the key washer in two or more places to give sufficient interference with the nut so that the nut will not turn. Refer to
and
for requirements.
2 After you tighten and torque the nut, you must indent the cup-type key washer in the correct number of places. Refer to Table 1 unless specified differently.
3 If the number of rounded slots in the nut or bolt is less than the necessary amount of indentations, the requirements of Table 1 do not apply.
4 If the key washer is the type shown in
, the requirements of Table 1 do not apply.
a Table 1 - Required Number of Indentations
| Thread Size | Number of Indentations | Spacing between Indentations |
|---|---|---|
| Less than 1.500 in. (38.10 mm) | 2 | See Figure |
| 1.500 in. (38.10 mm) to less than 2.500 in. (63.50 mm) | 4 | 60 degrees - 120 degrees |
| 2.500 in. (63.50 mm) to less than 4.000 in. (101.60 mm) | 6 | 6 slot nuts 45 degrees - 75 degrees |
| | 6 | 8 slot nuts 45 degrees - 90 degrees(*) |
| 4.000 in. (101.60 mm) and larger | 8 | 30 degrees - 60 degrees |
for indentation spacing.
5 For the cup-type key washers shown in
and
, you must make the indentations as shown.
(c) Key washer engagement
1 Table 2 - Required Engagement Measurements for Cup-Type Key Washers
| Thread Size | B Reference | C Minimum(*) Engagement |
|---|---|---|
| 0.190 in. (4.83 mm) | 0.043 in. (1.09 mm) | 0.026 in. (0.66 mm) |
| 0.250 in. (6.35 mm) | 0.042 in. (1.07 mm) | 0.025 in. (0.63 mm) |
| 0.3125 in. (7.94 mm) | 0.040 in. (1.02 mm) | 0.024 in. (0.61 mm) |
| 0.375 in. (9.52 mm) | 0.039 in. (0.99 mm) | 0.023 in. (0.58 mm) |
| (*) C Minimum = 0.6 B | | |
1 Make sure that a new key washer was installed.
2 Make sure that the key washer is not loose and cannot shake or rattle.
3 Make sure that the cup is bent as previously specified.
4 Make sure that the key washer did not move during the assembly.
5 If there is no axial pinch on the diaphragm portion of the key washer, you can move the washer with your hand through the limits of the tab clearance.
6 Cracking, tearing, scoring, gouging and smearing of the key washer or adjacent parts are not permitted.
7 Small tool marks from usual forming and bending procedures are permitted.
8 Indentations in one key washer must be of similar size and shape.
9 Indentations in the key washer must be formed into the rounded slots in the nut where the nut has such slots.