Of interest, we have had some Mag problems with our Dimona.   (Slick)

I had just completed its annual inspection which included the 2 yearly Mag
bench check where both main bearings were noisy so were replaced.  The bench
test was quite normal. Then reinstalled in the aircraft (not the easiest
with a Dimona as you would know).

A ground run was done . all normal, then a test flight . again all OK.

However during a second test flight, at around 800 feet, the engine suddenly
lost power. It would still run . (well sort of)  but could not maintain
height, so a precautionary landing was made back on the airfield.

I took the mag off and back to the engine shop. .. on the test rig, no spark
at all.  It was pulled apart and the condenser was stuffed.  A replacement
installed and all good again.

Still need to reinstall on the aircraft.

This mag / engine had a forced landing in Thailand about 12 mths prior to
their decommissioning.  The engine was sent back to Limbach and was
re-lifed, so we were real fortunate that it was zero timed. But not sure
about the Mag.   The engine has now about 160 hrs TT (also SMOH) in New
Zealand

I assume the mag was also the original.  We had it bench tested 2 years ago
prior to the first flight in New Zealand. All OK. 

When the mag was pulled apart, the condenser had what looked like somebody
had put some araldite around where the wire comes out of it. Presumably to
avoid any strain on the connecting wire.  However it also just may have been
leakage from the condenser.

So it may be something to consider with the ex Thai Dimona's that the
condensers in the Slick  Mags really need to be replaced if there is any
doubt that they are still the original.

I think there is actually a date stamp on the condenser which could prove
that.

 

Ian Williams

Drury

New Zealand

 

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