There I was at thirteen thousand feet, with my left wing on fire.
Okay, now that I have your total attention, I will tell you what actually happened. The flight began normally on a sweltering, summer morning in Dallas. I was making a routine trip to Shreveport (KSHV) for some practice instrument approaches. The 1,000-foot overcast was perfect for my mission.
Climbing off Addison (KADS) I was juggling my climb rate with the very warm CHTs (cylinder head temperatures). At 10,000 feet, I was barely able to make 400 feet per minute as the CHT on the left engine hovered around 400 degrees F.
“November five eight papa zulu cleared to one five thousand,” came the clearance from Fort Worth center. “Ah, five eight papa zulu is requesting one three thousand as a final today,” I responded as the PBaron struggled in the ISA +19-degree heat.
Levelling at thirteen, I was startled to see the left engine manifold pressure had declined to 27 inches compared to the right engine’s 31 inches. Hmm, not good, I thought.
Now, I was presented with the opportunity for action. The sudden loss of manifold pressure in a turbocharged engine could be from a leak in the exhaust system or a stuck wastegate controller. The first can be very serious; the second, not so much.
Which one is it? I thought. A leak could be dumping extremely hot gases into the engine compartment, creating a potential fire. A quick glance at all the engine gauges showed everything was normal. Forward movement of the left throttle produced no change. The left engine was running smoothly. I focused all my attention on the engine cowling for any sign of oil, smoke, or fire. It was all normal.
My options were to shut down the engine or keep it running and divert back home to Addison. I remembered a similar situation in my Beech Duke over forty years prior. And flashing through my head was the time I shut down a perfectly good right engine at FlightSafety in their Citation M2 simulator, after the instructor failed the left one. It gets really quiet with both engines shut down. Even in a simulator.
“Fort Worth, five eight papa zulu has an abnormal engine indication and would like to return to Addison.” “Roger, papa zulu, left turn and cleared direct to Addison,” came the response.
What we do in these types of situations depends on our experience, training, and risk tolerance. An engine failure in a piston twin at takeoff rotation requires instant action. But most other times, it is best to do nothing while we compose ourselves and look for the checklist.
Descending through seven thousand feet, the left engine regained its composure and responded normally for the remainder of the flight. Wesley Pearce, at Precision Aircraft Maintenance, found a completely severed exhaust pipe. Should I have shut down the engine? Did I make the right decision?
This time I was lucky.
Fly safe.
