Page 22 - Dec24

MAINTENANCE TIP
Spike in Engine Temperature Got Your Attention?
Check the temp stick when an engine temps out before making full power
by Dean Benedict
Years ago, a King Air 200 was in a shop for phase inspections and the owner was waiting for it to be released. It was the first phase inspection since he had purchased the aircraft. Unfortunately, the shop found both engines would not make book power – they temped out before reaching max torque – and, accordingly, the shop would not release the aircraft.
had a bad temp stick. I ordered and installed a new temp stick on each engine, and both engines made book power within the allowable temperature range.
The owner was pleased to say the least. A little later he put the engines on the M.O.R.E. (Maintenance On Reliable Engines) program and ran them another 5,000+ hours before selling that King Air and buying a 350.
Engine data plate
Not all PT6s are created equal. As I’ve said many times over the years, every engine is a tad different from the next. I’m fat. You’re skinny. The next guy is somewhere in between. It’s the same with engines. Every brand-new PT6 is brought to acceptance level in the test cell where it gets a good bit of customized tweaking.
One of the last things checked before a new engine makes its way
Here is the entire temp stick assembly, from the tip (left, over the engine inlet) to the wires going to the T5 harness
on the right. The tip of the temp stick fastens to a disrelated line, which makes good positioning over the engine inlet where there is metal mesh resembling hardware cloth.
The owner directed the shop to JETCAL the instruments and they did so. The results confirmed the engine gauges were reading correctly, so the JETCAL testing supported the shop’s position that the engines were not airworthy. At this time, these engines were about 100 hours from overhaul. The shop was eager to arrange the overhauls
or discuss replacement options. The owner, however, was not convinced.
He called me and we discussed the situation. I gave him a possible scenario that could make the engines appear to temp out when, in fact, they were still good to go. He obtained a ferry permit and brought his 200 to my shop. Sure enough, my hunch was correct: Both engines
20 • KING AIR MAGAZINE
DECEMBER 2024