Page 12 - Volume 12 Number 8

Summer Heat and Engine
Problems (Reprise)
by Dean Benedict, A&P
Recently, I’ve heard from several King Air owners who read this magazine and called me about my articles. All of these guys are fairly new to the world of King Airs and asked if someof my earlier articles could be run again. Even some longtime
readers of this magazine requested a “refresh” on some of my old articles. What follows is the article from the July-August issue of 2012. It addresses an engine problem that can crop up when the OAT is scorching hot.
The author pointing to the fuel bowl of the high-pressure fuel pump; the oil-to-fuel heater can be seen below it, behind a wire bundle. The most expedient way to troubleshoot the oil-to-fuel heater is to check the temperature of the fuel bowl after the engine has run for 10 minutes.
Hot weather conditions happen every day somewhere in the world, but right about now in the desert Southwest of the United States, we are feeling it big time. I received my first heat-related panic call back in May from a King Air pilot. He was at an airport near me, trying to take off and return home. One engine would not accelerate when he took the runway. He said he fire-walled the power lever but nothing happened, and to add to his concern, the idle was starting to decrease. Not a good sign. He returned to the ramp and conferred with a couple mechanics from a local tour operator who had suspicions about his fuel control unit (FCU), but suggested he give me a call.
As soon as I heard him recount his steps and symptoms, I knew exactly what was wrong. It happens every summer around here. The problem is with the oil-to-fuel heater. Yes, you read that right, the oil-to-fuel heater and no, I haven’t lost my marbles. Trust me, I have seen this happen many, many times.
Most people would immediately suspect a problem with the FCU, or maybe a P3 problem (bleed air going into the FCU) or possibly a Py problem (air going from the FCU to the prop governor). But before I “accuse” the FCU of any wrongdoing, I want to go upstream to the oil- to-fuel heater and look around.
The oil-to-fuel heater has a vernatherm inside which should
10 • KING AIR MAGAZINE
AUGUST 2018
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