Thursday, December 20, 2012

No Turning Back, No Turning Back. Unless...

As I pondered this blog posting and thought about the sequence of events as it transpired, I was reminded of the song "I Have Decided to Follow Jesus".  The lyrics of the song say, "I have decided to follow Jesus, No turning back, no turning back".  As the time has rolled by here in Uganda, I have had many new or slightly different experiences when flying.  From getting stuck in the mud to repairing my airplane with strips of rubber and bicycle inner tubes, it has been both a fun and educational ride thus far.  One thing that hasn't happened to me yet is having to turn back in mid-flight due to bad weather or anything else.  Little did I know that turning back would be the story of my next two flights.  Saturday would see me turning back and returning to Kajjansi because extremely bad weather prevented me from carrying out a medevac (the medevac was safely accomplished 3 days later by another pilot), but this is the story of Friday.

Friday morning I was scheduled to do the Karamoja shuttle flight in the morning.  Karamoja is a large area of northeast Uganda, and because many of our shuttle flights are flown in this area the flight has become known as the Karamoja shuttle, even if some of the stops are not actually in the Karamoja area.  We fly this shuttle three times a week, on Monday, Wednesday, and Friday mornings.  The Karamoja shuttle has become busier and busier this year as above average rainfall has made more and more roads impassable.  On this particular morning as I looked over my flight manifest and scoped out my flight for the day, I saw that it should be a fairly routine day and if all went well I would be back in Kajjansi shortly after noon.  I walked down to my airplane and prepared for my flight.  Fuel added, pre-flight checks completed, baggage loaded, passengers also loaded and briefed, checklist completed, start-up. 

I primed the engine, turned the key, and the throaty roar of my engine broke the stillness of the marshland that partially surrounds the Kajjansi airstrip.  Pre-flight engine checks went normally, and several minutes later the ground was steadily dropping away beneath me as I turned northeastward and contacted Entebbe radar on the radio.  As usually happens, Entebbe cleared me up to 9,500 feet, and I navigated around a small area of restricted airspace that exists over down town Kampala as I climbed.  With three passengers and baggage that morning I was not super heavy, but neither was I light and it was a relatively normal, slow and steady climb up to flight level 095.  As I approached my cruising altitude, I slowly lowered the nose, allowing the airplane to accelerate to cruise airspeed.  Cowl flaps closed, manifold pressure set, prop set to 2500 RPM, mixture reduced as I leaned the engine roughly before doing a fine lean in a few minutes.

This is something that I have done thousands of times over the years on almost every flight that I have ever made.  Every time, an attentive ear can hear the engine run slightly smoother as the fuel/air mixture becomes optimised for the altitude that I am flying at.  There is a small satisfaction that I get when I acheive a good, even lean over all of the cylinders and I know that both me and my plane are happy and contented as we settle into cruise.  Not so this time, however.  For the first time in my aviation career as I turned the mixture control counter clockwise to do a quick lean, my engine did not smooth out into the level, even hum of a contented engine.  Rather than that even "hmmmmmmmmm" as I brought back the mixture, the engine began to make a sound like, "ugugugugugugugugug" and I could feel unpleasant surges and vibrations throughout the entire airframe. 

Cue shot of adrenaline here. 

Normally I lean out the engine to a fuel flow of 14 gallons per hour (GPH) until engine temperatures stabilise and I can lean the engine more accurately (usually about 11-12 GPH).  This time as I reached 16 GPH, the engine began to run very roughly and the vibrations began. 

It doesn't take a rocket scientist to figure out what I did next.  I had just been running smoothly at around 18 GPH, and the problem didn't manifest itself until 16 GPH, so I quickly spun the mixture control the other direction, and put my airplane back into a happy state at 18 GPH.  Sure enough, the engine smoothed out and all negative indications went away.  On the off chance that it was an anomaly, I tried leaning out the engine one more time, but again as fuel flow was reduced to 16 GPH the engine began to cough and sputter.  Once again I enrichened the mixture and once again the engine smoothed out, running like a top.  Running like a top may sound fine, but in this case it was not fine.  I add fuel at the start of the day based on a normal fuel flow in cruise, and if I cannot achieve that fuel flow I won't have enough fuel to make the journey.  This fact, coupled with the fact that I was not keen to continue my flight with an engine that was obviously malfunctioning made the decision an easy one for me.  I started the turn to the right even before I keyed the microphone. 

"Fox-Fox, MSP is 38 miles out, returning to Kajjansi."

"Fox-Fox copies, MSP is returning to Kajjansi.  Is everything ok?" 

"My engine has begun to run roughly, and so I'm turning back to Kajjansi.  I have it set at a setting that is running smoothly for now, and I don't anticipate any trouble returning to Kajjansi.  Estimating Kajjansi in 18 minutes."

"Copy, estimating Kajjansi in 18."

After informing our flight following (Fox-Fox is aviation shorthand for "Foxtrot-Foxtrot", which means FF, short for "Flight Following") of the situation, I called back to Entebbe control and informed them of my situation.  Normally at this point if I were coming into Kajjansi on a regular flight I would descend smoothly, giving my passengers as nice of a ride as I can.  This time was slightly different.  Most of the return flight to Kajjansi would happen over densely populated areas, and if my engine decided that it was going to quit entirely I would be forced to land somewhere within gliding distance.  Unlike the movies, an engine failure does not necessitate extreme dips and lunges with radical control inputs from the pilot, but is smooth and controlled instead.  It's actually a lot of fun and highly enjoyable WHEN YOU"RE DOING IT ON PURPOSE!  Not quite as nice is the prospect of doing it on demand because of an engine that decided to stop working in flight.  Because altitude is your friend in a power off glide, I stayed at 8,500 feet over the city, an altitude that would enable me to glide to the shores of Lake Victoria if the engine failed, a much better option than trying to glide and set down somewhere in the city.  This meant that my passengers were subjected to a more aggressive descent as we neared Kajjansi, but that was the least of my worries at that point.

For the duration of the flight, my mind was filled with adrenaline charged vigilance and hyper awareness of every little sound that the engine made, as well as many short prayers being sent heavenward.  Having said this, nothing else out of the ordinary happened and I was able to land safely back in Kajjansi.  After shutting down and conferencing with our engineers, the initial guess was that cylinder 6 had a partial blockage of the fuel injector.  After cleaning the injectors later that day, the engine ran just fine.  As for me and my passengers, I prepared our other 206 and the rest of the day went by as normally as I had hoped that the entire day would have been, but with this pilot full of thankfulness and with a song ringing in my heart.

"I have decided to follow Jesus,
I have decided to follow Jesus,
I have decided to follow Jesus,
No turning back,
No turning back."

2 comments:

  1. Great post Dallas. Glad you're all fine. There's no substitute for good training, eh? See ya'll soon.

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  2. Thanks for all of these updates, Dallas. It's great to hear the good and the not-so-good to know how to pray for you specifically and thoughtfully. Stay soaring!

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