Aircraft Technical Manual
Jabiru Aircraft
Pty Ltd
J120, J160, J170, J200/J400, J230/J430, J250/J450 Variants
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ISSUE
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Dated: 29th October 2014
Issued By: AS
Page: 29 of 298
2.19 Torque Values (In Fibreglass)
Unless noted otherwise, all bolt torque settings detailed within this manual are for clean, dry threads.
When checking fastener torque, use the following procedure:
-
Ensure the fastener to be checked is clean and dry before proceeding.
-
Where a reversible wrench is being used, set the torque to a value slightly below the target
torque and LOOSEN the fastener slightly (approx
1/3 or a turn). The wrench should “click” –
indicating that the fastener had maintained its set torque. If the fastener torque has reduced
significantly it may be an indication of damage or degradation to the assembly and should be
investigated.
-
The fastener is first loosened slightly to ensure that it is free to move on its threads. If this step is
not carried out it is possible for the fastener to corrode in place. If that happens, the friction of the
corrosion will seize the fastener, ensuring that
it appears to “pass” torque checks but in fact has
lost tension and is no longer holding the assembly correctly.
-
Tighten the fastener smoothly to the set torque. Any jerks or bumps when tightening can cause
the reading to be obtained prematurely.
-
The torque must be obtained while the nut is turning. If you stop to reposition the torque wrench
and then the required torque reading is obtained without the nut turning, the nut needs to be
loosened a little and then tightened again so the torque reading is obtained while turning.
Table 2-8
– Recommended Bolt Torque Values (all J-series)
Bolt Size
Torque (Inch.lb)
(Core-mat or thin laminate)
Torque (Inch.lb)
(Thick, glass-only laminate)
AN3
20 - 25 (1.7
– 2.1lb.ft)
Up to 4 lb.ft
AN4
50 - 70 (4.2
– 5.8lb.ft)
Up to 8 lb.ft
AN5
100
–140 (8.3 – 11.7lb.ft)
Up to 18 lb.ft
AN6
N/A
Up to 24 lb.ft
AN4 Propeller
72 (6lb.ft)
N/A
These values relate only to steel nuts on oil-free cadmium plated threads.
For Engine Bolt Torque Values see Engine Maintenance Manual.
The above values are recommended for all installation procedures contained in this Manual, except
where other values are stipulated.
The above values are not to be used for checking tightness of installed parts during service.
