It was cold at altitude: minus 39 degrees C. It was cold when we landed too: 9 degrees F. As I shut the Cheyenne down, I cautioned my wife, Cathy, to stay in the airplane until I could get the car and come get her and the dog, Corbett. She needed no persuading.
Just then a wisp of white smoke caught my peripheral vision. It seemed to come from the right side of the nose of the airplane. I got out, closing the airstair door behind me to keep whatever heat we had in the cabin. Sure enough, a small amount of white acrid-smelling smoke was coming out of what looked like a breather tube just forward of the heater exhaust. The heater exhaust is easy to spot on all Cheyennes because a trail of exhaust stains the fuselage behind it, in a pattern like the tail of a comet.
I knew the heater had been working properly in the air. Though bleed air from the PT-6 turbine engines is used to pressurize the cabin, the engines aren’t big enough to support the heating function at altitude. This explains the Janitrol heater, with which I have a complicated and not necessarily happy history. It is a temperamental SOB in my experience.
The smoke from the airplane quickly cleared only to be replaced by smoke coming from Cathy, who had an understandable skepticism about staying buttoned up in an aircraft on the ground with smoke billowing from it. So, we all got out, shivering. Not a good start to a Christmas vacation in New Hampshire.
Perplexed, I knew that departing from Lebanon, New Hampshire, in the dead of winter without a functioning heater was a no-go MEL (minimum equipment list) item. I called Jason Archambeault at Signal Aviation. He had sorted through a complex prop issue last summer, and I knew him to be very nice and a good communicator. I also knew him to be an actor in his spare time, which may explain his communication skills.
What I needed more than communication, though, was cabin heat. Jason agreed to test the heater by applying a power cart on the ground and running the heater. Sure enough, he reported: no heat. And this: In my quizzical interest in the smoke, and thus distracted, I had shut the engines down without turning off the windshield and pitot heats. Sure enough, the power cart experiment had melted the pitot covers right off the airplane. So far, not so good. We agreed to get the airplane in the hangar after the weekend and take a closer look in a warmer environment.
I called Jim Celantano in Groton, Connecticut. Jim works at Columbia Air Services there and is a Cheyenne guru. In the past, when nobody could get reliable heat out of our airplane, Jim solved the issue. The only problem was that Jim was short-handed during the week between Christmas and New Year’s Day, and loaded up with clients already in the shop. They were screaming for their airplanes.
“Call me next Wednesday and I’ll see if I can work you in,” he said.
All airplane owners know the feelings of a supplicant. When you are away from home base and a maintenance issue comes up, you are totally, completely, undeniably dependent on the kindness and expertise of strangers. I have been driven to prayer more frequently for this condition than for any other so far in my very lucky life. If you can’t find somebody to help, you are stuck. If you can’t get it fixed, you are stuck. The tap, tap, tap of your family’s toes and their crossed arms and that “we could have flown commercially” look make the compelling case for action. It is, for me, a most uncomfortable feeling; it has driven me to the desperate acts of a beggar.
I called Bill Turley of Aircraft Engineering in Bartow, Florida. Bill has taken care of my airplanes since 1983 — we know each other very well. He also works weekends, even after all these years. And holidays too sometimes. He said to start an engine to provide generator power and see if I could get heat. There are several switch positions, and maybe the heater hadn’t been properly configured during the power cart test. I did this. I started the left engine, put the generator on line and prayed. No dice. No heat.
Remember this: I started the left engine.
On a Tuesday morning after the holiday, I met Brian Shepa. He was dispatched to attach the power cart again, with the airplane outside. I ran the heater from the cockpit. With 27 amps, I turned on the heater control. Brian gave me a thumbs-up sign from the right side of the airplane. For a moment he had felt warm exhaust. Before I had a chance to feel relief, the exhaust turned cold. You can’t fly 1,100 nautical miles with heat that lasts 10 seconds.
The airplane was moved to Signal’s spotless maintenance hangar. I know how hard it is to keep a house clean in the New Hampshire winter, so I marvel at this pristine facility. With Bill on the phone and Jason and Brian in the shelter of the hangar, they ran the diagnostic algorithm. Was there spark? Yes. Was there power to the combustion blower? Yes. Was it turning? Yes. (This creature blows preheated air into the combustion chamber where it meets jet-A and a spark, and, boom, you’ve got heat.) Was there fuel? No.
Aha. No fuel, no fire. Bill informed us that the fuel pump had been replaced just a year ago. Like I said, my relationship to this heater is a complicated one. This lack of fuel led to a complex set of interactions between the mechanics situated two climates away from each other. There were filters and valves, pressures and circuits. The inner workings and hidden mechanisms of the Janitrol heater are something to behold and may explain some of the troubled history I share with the device.
I promised not to help (Bill says it is time and a half if you help). I promised not to talk. I was reminded, though, of the medical diagnostic puzzles so artfully described by Atul Gawande and Jerome Groopman, among others, in The New Yorker magazine. I watched as the pros poked, twisted and puzzled. Then this: Bill called and said it was likely that the heater fuel pump is dependent on incoming fuel brought to it from the right wing by, you guessed it, the right boost pump.
Aarrrrggghhh.
In none of our testing had we run the right boost pump. Remember, when I tested the heater, I started the left engine so that I could see if smoke wafted up from the right side. I didn’t want a turning prop to wash away the evidence.
Now came a call from Jim Celantano.
“I can’t help you.”
But he did. When I told him the story he confirmed that the right boost pump is necessary for heater operation and then went on to explain the symptoms that started the whole dance in the first place.
“I bet you were in ‘auto’ mode,” he surmised.
(I was.)
“The combustion blower cycles with the fuel. I bet the smoke was a little bit of fuel that burned as you shut down. I’ll bet the heater is working fine.”
I called Jason, who said, “We pretty much just came to that conclusion ourselves.” With the thought that we had several hours of maintenance tied up in a heater that was probably working fine, I watched as Jason and Brian put the heater back together. I had to leave, but they promised to let me know if the heater worked when it was reassembled.
With the right boost pump on, heat came out of the vents. They buttoned everything up and signed off. All that was left was a test flight prior to putting Cathy and Corbett on board. For those of you familiar with New Hampshire winters, you will know that you can’t just declare a test flight and expect it to happen. The next two days were essentially zero-zero as warm air melted snow and made fog and, even better, freezing fog.
The test flight would be a long one: 1,100 nautical miles back to Tampa with a stop in Wilmington, North Carolina (KILM). We loaded up. I started both engines and gingerly flipped the heater on. Reassuring heat flooded the cabin. No flame, no sparks, no smoke.
We taxied out. Still warm. The visibility was three miles mist, 100 few and 1,300 overcast. Tops were at only 4,800 feet. Still warm, we climbed to FL 220. Outside air temperature was minus 22 degrees C.
So it was, all the way down the Eastern Seaboard, laboring against 61 knots of headwind. But the air was smooth and we were warm. Only an airplane beggar knows how good this feels.
