[RBR]

I am about to torque the blue fittings associated with my fuel tanks, the fuel vent and fuel feed lines.

Searching the forums has not quite answered my query. I turn to the experts.

Page 183 of the Standard Aircraft Handbook, the section on aircraft plumbing, would indicate I need a torque value of 75-125 inch pounds for a -4 flared fitting. Yet the AEROQUIP specification sheet is markedly different at 100-140 inch pounds.

Which document is more correct?

Many thanks,

Richard

 

[MNAv8or]

If they are Aeroquip fittings then use the aeroquip specification torque. The Standard aircraft handbook is a guidline to go by but always follow the manufacturers specs.

In the aircraft shops that I haved worked in, I can't remember a single time seeing someone torque an AN fitting. Usually just go until its nice and tight and have never had a problem in over 10 years. I do know that if you use the standard torque on AN fittings on the landing gear system of a Beech 1900D they WILL leak as the torques do not get the lines tight enough. And if they leak then you have to yank the power pack and get it rebuilt!

Always follow manufacturer specs and use the standard handbook if you can't find anything from the manufacturer.

 

[pierre smith]

Here's the easy way...

....to torque them:

http://www.vansaircraft.com/pdf/Torque_Spec_Aluminum_Fittings.pdf

Regards,

 

[N941WR]

Richard,

After you torque each fitting, mark it with torque seal. When I have done a tech inspection on planes I have a standing rule; if the fittings are not marked, then they are not torqued.