Yep, they are available but our torque wrenches have to have calbration certificates and be recertified regularly. We then have to take drag resistance into consideration when using them.
These are screwdriver torque figures, very difficult to measure in reality.
The tyres are checked for inflation every night on airliners, you don't see the engineers torqueing the valve caps on... they would be laughed off the flight line. I have routinely checked inflation of 30 to 40 tyres every night, - just a small part of putting the aircraft to bed.
It is the same as the rocker cover screws on the piston engines where what they want is a calibrated 'tweek' of the wrist. The trick is that the procedure has to have a 'figure' that can be recognised. To the LAME that is translated as a feel... just as screwing on a valve cap is. Using any tool is asking for trouble as overtightening is obviously much worse.
The same applies to the spark plug HT lead nuts, they are just tweaked to a little more than finger tight. We still have pilots that seem to think it is criminal when they manage to undo one during their pre-flight. The reality is that anyone overtightening the nut should be shot...
Again while we torque the spark plugs it is extremely important the caps are not overtightened. They are never torqued using a tool, well not that I have ever seen.
There was mention of tread depth on the tyres also.... I have worked with airlines where would allow wear to go through so many plies, on the last retread you could even allow it to go beyond the retread limit.
The tyres are marked with the number of retreads, if you let the wear go too far then you would lose out on any further retreads.
Talk of measuring tread depth is a little off the mark.
If any mechanic I supervise tried telling me that he had torqued a tyre valve cap I would be very suspicious. I would most certainly be obliged to go and recheck and see just what had been done.
Perhaps some guys do have special little tools that make it impossible to overtorque them, I can't remember seeing them in my time.
When you work in the Islands or Africa you have to be wary of guys marching out with a 1/2 " drive wrench and trying to tweak them to 10 ft lbs, that happens much more often than it should also.
With the modern 'metric' educated youth you also find that they have trouble equating things in real terms. One US gallon is about 4 jugs of beer.
Twenty pounds pull on an arm of 12 inches means nothing at all to these guys. The LAME or supervisors need to be on the ball.
Last edited by baron_beeza; 14th Jan 2013 at 09:36.