Full-Service Mistake

Self-serve fuel is a fact of life for automobiles, why dont pilots pay more attention to what goes in the tanks?


For many pilots, the end of the flight is the beginning of a routine. They land, taxi to the ramp, go into the FBO.

If theyre planning another leg, theyll order fuel, use the restroom, check the weather and maybe have a snack. They pay the fuel bill and walk back to the plane.

If theyre home or planning to spend a day or two, they put in a fuel order and leave.

Sometimes its the worst thing you can do.

For example, a Cessna 421C crashed in good weather in San Antonio, Texas, killing the pilot and one passenger instantly. Another passenger was seriously injured and died several days later. The pilots gamble came during the preflight and engine runup.

The flight was operating as an air ambulance, carrying a pilot and two nurses. It had made a trip from San Antonio to Del Rio, Texas, earlier that morning and, on its return, the pilot ordered 30 gallons of avgas in each wing tank. He called Flight Service and got a weather briefing, then filed an IFR flight plan to Eagle Pass, Texas, where the airplane and crew were based.

The airplane took off, and within a minute the pilot reported a problem and requested a return to the airport. He was cleared to land, but both engines were trailing thick black smoke. The plane crashed a half-mile from the runway.

An investigation determined that the gasoline in the wing tanks had been contaminated by Jet A. Two labs confirmed that the fuel was about half 100LL and half jet fuel.

The FBOs paperwork showed that the aircraft had been serviced with 100LL, but the meter readings on the fuel trucks showed the fuel had been pumped from the Jet A truck. Although the airplane was in compliance with AD 87-21-02, which required the installation of fuel filler restrictors in the wing tanks, the FBOs fuel truck was not equipped with a restrictor nozzle. The fuel truck was owned by the fuel vendor and leased by the FBO. The nozzle had been in the vendors warehouse for two years.

The potential for trouble is there for every pilot. Some pilots routinely supervise the refueling of their airplanes. Some check the filler caps after the fuel is pumped. Some sample the fuel for water before the fuel truck gets there and again after it leaves. Some pilots insist on pumping the gas themselves. Few are the pilots who do all of the above.

Does it show lack of trust? Sure it does. It shows lack of trust in the training of the refueler by the FBO and human factors in general. Think about your home airport and count how many different faces youve seen driving the fuel truck in the past two years.

Verifying that the correct fuel truck is parked in front of your propeller is the first step, but it doesnt stop there. Problems also can be stopped during preflight. The fuel samples odor of kerosene, the separation of the fuel in the tester, the greasy splash where the sample was emptied on the ramp and the color are all there to see.

In the case of the Cessna 421, the next chance to break the accident chain came after the engines were started. Cylinder head temperatures would have been very high during taxi and runup. In any case the runup would have shown (after the most casual check of engine instruments) that things were close to meltdown.

The accident report contains no witness accounts that there was or was not a runup. There are some pilots, particularly among Part 135 operators, who do quick mag checks while they taxi, get clearance and move right out on the active with a rolling takeoff. It has a nice look but can be a deadly game of Russian roulette.

On the takeoff roll, the engine gauges probably showed pegged cylinder head temperatures, with the distinct beginnings of detonation well before liftoff speed. The takeoff roll was probably much longer than normal. The engines were literally melting down. Once airborne, the right engine went first, and the pilot seemed to be proficient enough to get it feathered promptly, but power was fading fast on the left engine – with full-scale detonation underway.

As the air ambulance settled toward the ground, it approached a small stand of oak trees, surrounded by open field. There may have been too many things going on for the pilot to notice. In any case, the crash was into the trees.

A casual glance at the fuel truck is all it would have taken.

-by Raymond Leis

Raymond Leis is a CFII and ATP with more than 23,000 hours.


Please enter your comment!
Please enter your name here