Perhaps the ultimate unforgivable sin in aviation in aviation is fuel exhaustion, and while you may never do it chances are you’ll come close… I did. How could anyone fly beyond the range of his or her fuel load, you might wonder? This lesson comes with a story, and that’s where we’ll begin…
THE LONG CROSS-COUNTRY
I was taking my first long trip in a newly acquired Beech Sierra. Starting after work on a Friday afternoon, the mission was to fly the roughly 570 nautical mile trip from my home at Cleveland, Tennessee (near Chattanooga) to Butler, Missouri (south of Kansas City). The Sierra plugs along at a respectable 128 knots on a little over 10 gallons-per-hour. With 48 gallons useable fuel it has about a 3.8-hour endurance with a 45-minute reserve. Even with a forecast average five-knot tailwind I’d have to stop for fuel along the way.
I like to stop at Sikeston, MO (KSIK), in Missouri’s southeastern “bootheel” region. I’d also heard rumors of $1.75 per gallon 100LL at Kennet, MO (KTKX), very near Sikeston. A quick look in AOPA’s Airport Directory told me SIK’s fuel desk was open until 5 p.m., and TKX until seven — critical information for a flight over few refueling opportunities that would start late in the late afternoon. To confirm this critical information I phoned both Sikeston and Kennet before preflighting the Beechcraft. I had about three hours worth of fuel on board already — enough to comfortably make Kennet or Sikeston before either closed (plus, the changeover from Eastern to Central time zones would work in my favor).
THE START OF THE PROBLEM
The Sierra had a balky starter, and it just wouldn’t fire up to taxi to the fuel pump. Complicating this was my lack of familiarity with the starting peculiarities of this particular airplane — I succeeded in flooding the engine and wearing down the battery in my attempt to tame the recalcitrant starter. I put the battery on a charger as my departure window (takeoff time required to make it to my fuel stop before it closed) ticked away. I looked in the Directory again and found that Paris, TN (KPHT), almost directly on my route was also open until 7 p.m., but was one half hour less distant. When the battery was finally reinstalled and the engine successfully started, I was extremely tempted to forego the departure fueling and simply take off westbound… it was already almost six p.m. Eastern time, and my destination was almost two hours away.
THE KINDNESS OF STRANGERS
Sanity prevailed, and I topped off the tanks before departure. With a full fuel load I took off and picked up my instrument clearance, dodging some late-afternoon cumulus build-ups along the Cumberland Plateau. I carefully leaned the fuel/air mixture and confirmed my expected flow rate. The panel-mounted (but VFR-only) GPS told me the forecast of a light tailwind was accurate. Like most non-Cessna airplanes, the little Beechcraft requires switching back and forth between fuel tanks to balance the load in flight — and to get to all the fuel in the airplane. So I began the meticulous process of recording “switch times” and approximate fuel burn out of each wing tank (half an hour = five gallons burned between “switches”). At each “switch” I also recomputed my Estimate Time of Arrival (ETA) at Kennet, and the total fuel burn required to get there. If either the total fuel burn would exceed 40 gallons (leaving a 45-minute reserve) or the ETA was after about 6:45 p.m. (to get fuel before the FBO closed), then I’d fall back on Plan B and land at Paris. A landing there would still leave a long, but do-able, cross-country before reaching my final destination.
Soon the numbers I saw convinced me, and I called ATC to request a destination change to KPHT (Paris). I called ahead on Paris’ UNICOM frequency and got no answer. Finally, the pilot of an Archer in the Paris traffic pattern told me the FBO was closed but that a self-service fuel pump on the field was not. “That’ll work,” I replied in thanks, and I landed … only to find some glitch with the pump’s credit card reader. About then I saw a Piper Tomahawk taxiing out. “Piper taxiing at Paris,” I called on the UNICOM frequency, “is there any trick to getting the fuel pump started?” To my surprise this kindly stranger taxied back to the ramp; the pilot got out and tried valiantly to start the pump, without success. (I apologize for forgetting your name, kind stranger, but thanks for trying!)
THE DECISION, THE PLAN
I looked at my charts and decided I could just make my destination of Butler, MO (KBUM) with my planned reserve if I could get a “direct-to” clearance and the tailwind held. I’d fly north of Springfield, Missouri (KSGF); KSGF has airline service and that usually means an FBO open until about 10 p.m. Any adverse change in groundspeed or longer than a “direct” clearance meant I’d have to land at Springfield, or one of the numerous small airports that dot Missouri’s southern border. If fuel wasn’t available, I’d just have to stay until morning. Plan in mind, I took off.
I picked up my clearance (the haze was so thick I was hesitant to fly VFR at night), quickly telling Air Traffic Control (ATC) that I had a VFR GPS on board, and would like direct Springfield if able. I was getting a little nervous about stretching my range all the way to my original destination near Butler. The helpful controller looked at my flight plan and told me I could have direct Butler if I wanted, and with that little nudge, I accepted. ETA (according to the GPS) was two hours, six minutes.
…AND THINGS GET COMPLICATED
Some quick figuring told me I could make it — barely — with about 30 minutes of fuel remaining. The regulations address preflight planning and require that I ‘plan‘ for a 45-minute reserve for a “legal” IFR or night VFR flight. I had adhered to them in the planning phase and now that I was airborne, my legal obligations associated with them were meaningless. Note: I said my ‘legal‘ obligations. It was late, and I was tempted. But less than a minute later I dialed in KSGF (Springfield, the closer destination) and found I could be there in half an hour less. Just seeing the numbers made me feel much better.
I told ATC I’d like “direct Springfield” if I could get it, and to change my destination to that airport. He gave me the clearance, and as I got closer my fuel calculations told me I’d arrive with just my 45-minute reserve intact. When I later fueled up at Springfield, I confirmed I had exactly 45 minutes’ fuel on board when I’d landed.
WHAT I’VE LEARNED
You are free to evaluate the wisdom of any of my choices along the way. In fact, I encourage it… especially if it gets you thinking about your own fuel planning and decision-making. I’ve already learned a thing or two from my adventure, and am fortunate enough to be able to share them with you. Here’s my short list of negative externalities. If any one of these factors affect your flight, step back and reassess your plan.
- Late afternoon departures (with fuel options closing for the night).
- Departing with less than full tanks: Weight, balance and performance permitting — fill the tanks prior to each departure.
- Leaning technique: If you find that you’ve delayed in its application or applied improper fuel leaning your range planning may now be inaccurate.
- Groundspeed changes: Any variance from the forecast makes your preflight range planning inaccurate.
- Fuel management: Sloppy (uneven) tank-switching or record-keeping may cause a tank to run dry unexpectedly, with the possible result of vapor lock and engine stoppage.
- Fuel unavailability: If there’s no fuel where you expect there to be fuel, sit down and calculate a brand new, fresh, flight plan.
- Temptation: It’s better to spend the night in a hotel than to spend it in the woods, nursing an injury, next to a wrecked airplane (the only good news is that it won’t burn).
- Unexpected Help From ATC: Air Traffic Control does not always know best. In my case, the controllers help (and unknown to him) actually dangerously encouraged my “keep going” mentality. If you have doubts, listen to the voice inside your head first — before listening to the one inside your headset.
DEFENSE — Six simple steps that will keep you out of trouble:
- Plan the flight, and fly the plan. If the flight changes, the plan has to change, too. Sit down and do it right.
- Do not rush your preflight and take the time to fuel up before departure. The airplane is fast enough in the air that you don’t have to be fast on the ground. If the aircraft can’t make up the time, neither can you — make a new plan.
- Lean the mixture as recommended by the aircraft’s pilot operating handbook.
- Monitor fuel burn rate, groundspeed, ETA and fuel-remaining estimates. That means multiple checks during a flight. It’s simple (it can even be fun) and it makes you a better pilot. When was the last time you did it?
- Accept the possibility of diverting, and plan for it. Simply knowing you might wind up at a specific ‘somewhere else‘ isn’t good enough. The human brain does not like to give up plan A for a course of action that’s unplanned — even when it represents a better idea. Calculate the parameters that would automatically cause you to divert. Plan it, so you can do it.
- Retain command at all times. A suggestion from ATC is just that — do not blindly follow ATC directives without good reason.
BOTTOM LINE: I doubt pilots knowingly take off with too little fuel to complete a flight. More likely, the relatively high number of engine failures resulting from “running out of gas” stems from disregard to one or more of the above six steps. Avoid temptation and you’ll avoid the unexpected. It’s not fuel, it’s life — don’t cut it short.