I have been busy at work, and keeping my equipment in top shape has been a continuing challenge.

N833DF was in for its annual from May 13th to the 26th. Thats a solid two weeks, which will most likely be typical for the twin. I continue to invest in improving reliability and knocking out problems before they surface, but I am not there yet.

I was excited to be getting my airplane back, and had to work hard to fit in a few flights with the work schedule I am keeping. Trouble surfaced right away in the shape of very high fuel flow indications on the right engine; accompanied by somewhat higher EGT readings and warmer oil temps. Something was wrong with the right engine, so back it goes.

Rob thought it was most likely a fuel sender unit, and soaked it in cleaner for the first try. That didn’t work, so we sent the unit away to be rebuilt.

With the newly rebuilt fuel sender back, the fuel flows (really pressure translated to flow) are now acceptable. EGTs are still high, but more importantly the oil temperature now shot up toward red-line. WTF?!? Could something else be wrong or was the fuel sender really the issue at all?

Now the theory became either the vernatherm or the oil temperature sender itself. Rob had a vernatherm available from a Navajo, so we tried a test flight with that first. Temperature was climbing on the ground for the right engine, but I wanted a complete test, so I took off and flew up to Wilmington IFR. Temperature in level flight was fine – within 10 degrees of the left engine at 210 deg F.

Flying an instrument approach into ILG, the temperature of the left was steady, but the right rose steadily to 220 degrees or so on the way down the glideslope. At this point, I’d report when I got back that we have made an incremental improvement, but are not there yet. Arriving GED and flying the GPS22 approach there, I noticed the same pattern of temperature rise with reduced power. That is counter-intuitive. Upon landing, however, the temperature really shot up – right to redline. Wow – whats going on?

The next step was to swap the oil temperature senders on the engines and see if the problem moved to the left engine. Long story short – I did another test flight and found the LEFT engine going to redline now. YES!! It was the oil temperature sender after all – so that will get replaced later this week.

During the post-flight wipe down, I found a nick on the right prop that is probably due to the multiple run-ups at GED. I’ll have that dressed, and the airplane should be ready for zero squawk flying next weekend.

Owning and airplane can be frustrating, expensive and a wonderful thing. When I realized the issue was found and soon to be resolved, I got back to enjoying it.


By fdorrin

Recently rated Gulfstream 280 pilot, working on instructor qualifications. WestWind and Astra corporate jet flight instructor. Contract corporate pilot. Own and operate a PA30 Twin Comanche. CFII; MEI; ME-ATP; SES; Typed in DHC-8, B-25, IAI-1124, IAI1125, G100, G280. Retired engineer / executive - Delmarva Power, Conectiv Energy, and PEPCO Holdings, Inc.