DOC AIRBUS | AMM A320FGeneral Torque Tightening Techniques [IAE]
TASK 70-23-11-911-013-A
General Torque Tightening Techniques
1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Referenced Information
3. Job Set-up
Subtask 70-23-11-869-052-A ** ON A/C NOT FOR ALL
Subtask 70-23-11-911-052-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 02:19:32 UTC
General Torque Tightening Techniques
1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| TASK 70-23-11-911-011-A | Check for Re-use of Self-Locking Fasteners |
| TASK 70-23-11-911-012-A | The Procedure to Use Torque Wrenches and Power Tools |
Subtask 70-23-11-869-052-A ** ON A/C NOT FOR ALL
A. Not Applicable
4. ProcedureSubtask 70-23-11-911-052-A ** ON A/C NOT FOR ALL
A. General
(1) The torque values specified in the maintenance manual must always be used.
(2) The use of a lubricant is very important to get the correct bolt tension. This is because most of the torque becomes friction at the nut and bolt bearing surfaces and the screw threads.
(3) Unless specified differently, the given torque values only apply when the screw threads and bearing surfaces are correctly lubricated with clean engine oil of an approved specification.
(4) Where no special torque values are given the standard torque values must be used.
(5) The torque values used for J-threads are the same as those used for standard screw threads.
(6) The torque values must be specified as follows:
(7) Torque values in lbfin (mdaN).
(8) Angles of turn in deg.
(9) Extension values in inches (mm).
(10) When a part to be torque tightened is hot, sufficient time must be given for it to cool (i.e. to a temperature equal to that of its adjacent parts) before it is fully torque tightened.
(11) The joints between flanges, or between mating surfaces, must be very carefully made during the assembly. Also, when snap-fit joints are made, the mating surfaces must be correctly engaged before the full torque value is applied. Unless a special procedure is given in the assembly instructions, some of the bolts will be installed at equal distances. They will then be equally tightened, until the mating surfaces are fully engaged. The bolts can then be tightened to approximately 75 percent of their full torque value, in a set sequence (e.g. 180, 90, 45 deg) so that the bolts and flanges do not become locally stressed. The full torque value can then be applied, in the same set sequence.
(12) All torque values must be applied slowly and smoothly, to get the most accurate and constant results. There will be times when the specified torque values can not be applied. At such times, an accurate analysis must be made to find the correct torque value to be applied.
(13) When minimum torque values are given for castellated nuts, they must be tightened to the specified limits. If necessary, tighten the nut again to align the lock-slot.
(14) When minimum and maximum torque values are given for castellated nuts, align the lock-slot but do not tighten the nuts by more than the maximum limit. If this is not possible, a different nut must be used.
(15) The nut must be turned rather than the bolt wherever possible.
(16) Instructions for the use of torque wrenches must always be followed (Ref. AMM TASK 70-23-11-911-012).
(17) Self-locking nuts for re-use
(18) Definitions:
(19) Self-locking or prevailing torque:
The torque required to overcome kinetic friction between the fastener mating threads with the locking element fully engaged and with no axial load on the assembly.
(20) Breakaway torque:
The torque required to overcome static friction between the fastener mating threads with the locking element fully engaged and with no axial load on the assembly.
(1) The torque values specified in the maintenance manual must always be used.
(2) The use of a lubricant is very important to get the correct bolt tension. This is because most of the torque becomes friction at the nut and bolt bearing surfaces and the screw threads.
(3) Unless specified differently, the given torque values only apply when the screw threads and bearing surfaces are correctly lubricated with clean engine oil of an approved specification.
(4) Where no special torque values are given the standard torque values must be used.
(5) The torque values used for J-threads are the same as those used for standard screw threads.
(6) The torque values must be specified as follows:
(7) Torque values in lbfin (mdaN).
(8) Angles of turn in deg.
(9) Extension values in inches (mm).
(10) When a part to be torque tightened is hot, sufficient time must be given for it to cool (i.e. to a temperature equal to that of its adjacent parts) before it is fully torque tightened.
(11) The joints between flanges, or between mating surfaces, must be very carefully made during the assembly. Also, when snap-fit joints are made, the mating surfaces must be correctly engaged before the full torque value is applied. Unless a special procedure is given in the assembly instructions, some of the bolts will be installed at equal distances. They will then be equally tightened, until the mating surfaces are fully engaged. The bolts can then be tightened to approximately 75 percent of their full torque value, in a set sequence (e.g. 180, 90, 45 deg) so that the bolts and flanges do not become locally stressed. The full torque value can then be applied, in the same set sequence.
(12) All torque values must be applied slowly and smoothly, to get the most accurate and constant results. There will be times when the specified torque values can not be applied. At such times, an accurate analysis must be made to find the correct torque value to be applied.
(13) When minimum torque values are given for castellated nuts, they must be tightened to the specified limits. If necessary, tighten the nut again to align the lock-slot.
(14) When minimum and maximum torque values are given for castellated nuts, align the lock-slot but do not tighten the nuts by more than the maximum limit. If this is not possible, a different nut must be used.
(15) The nut must be turned rather than the bolt wherever possible.
(16) Instructions for the use of torque wrenches must always be followed (Ref. AMM TASK 70-23-11-911-012).
(17) Self-locking nuts for re-use
CAUTION:
SELF-LOCKING NUTS THAT ARE NOT SATISFACTORY FOR RE-USE CAN BACK OFF, WHICH CAN CAUSE DAMAGE TO THE ENGINE OR THRUST REVERSER.
(a) Self-locking nuts must be checked for re-use prior to re-use (Ref. AMM TASK 70-23-11-911-011). (18) Definitions:
(19) Self-locking or prevailing torque:
The torque required to overcome kinetic friction between the fastener mating threads with the locking element fully engaged and with no axial load on the assembly.
(20) Breakaway torque:
The torque required to overcome static friction between the fastener mating threads with the locking element fully engaged and with no axial load on the assembly.