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Dodgy Torque meter !

G-EWAW Torquemeter 004I’ve been experiencing a problem with my Torque meter recently. It was an intermittent problem, but it needed rectifying all the same. Basically, it was impossible to keep it below 40PSI on run up, which it should easily have been capable of and, it would almost immediately begin to show 70PSI. Once in flight, it would read accurately, (more or less), but if you put the machine into auto, it wouldn’t read any less than 70 PSI so it was clearly not a happy bunny. Furthermore the needle would oscillate  rapidly between two narrow levels (e.g. 70psi – 71psi).

G-EWAW Torquemeter 003

We tried a number of things, but these only helped for a short while before it would return to it’s dodgy self. The last resort was to take the engine out, strip the gearbox down and get to the torque meter orifice where PDG suspected there was probably a blockage. It’s a bit of a job to do, but it needed doing so, at the last 100 hour check, we decided to have a go at it. The procedure involves removing the engine, the engine accessories and the fuel system followed by the compressor, the gearbox and the turbine. Once the gear box is out it needs to be split in order to remove the torque meter piston. This will then allow for the carbon deposits torque meter orifice to be cleaned.

G-EWAW Torquemeter 005Once this is done, it all has to go back together again. A duplicate inspection is undertaken of the engine mounts,  driveshafts and engine controls. The fuel system is then bled, followed by an oil flow check and then finally ground runs including leak checks of all oil and fuel onions. On ground runs, the meter seemed to be behaving with the exception that it still had an oscillation at whatever level it was displaying. The needle was always where you expected it should be, but this oscillation was irritating. Richard tried bleeding air from the back of the meter itself and then the suggestion was to fly it around for a few hours to see if it settled down. After 5 hours of flight it still wasn’t great so PDG reversed the technique and actually introduced air to the system; this didn’t improve anything so we’re left with swapping out the gauge itself which we will be doing shortly. Hopefully this will then prove whether or not the gauge is faulty also – if so, I guess that will have to be swapped out too. All in all it’s been a bit of pain in the ar*e episode, but a necessary one to get the thing working properly.

I’ll keep you all posted!!

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