AVIATION SAFETY NEWSLETTER
Thought for the month.....
You never see a fish mounted on a wall with its mouth shut!
Almost Stupid.... I have had the opportunity to study
how human factors are always involved in an accident. I understand how these factors often link together in a
disastrous chain and that accidents are actually complex events that can occur despite our best efforts. There
are many things that influence our decision-making and we're all susceptible to making poor decisions. These are
the consequences of being human, not the result of being stupid. However, there is one mishap that comes very
close to being stupid - running out of gas.
In any given year fuel mistakes by pilot's account for roughly 10% of the accidents by general aviation. There are usually two distinct types of errors leading to either fuel starvation or fuel exhaustion. Fuel starvation occurs when there is fuel aboard the aircraft, but it does not reach the engine, either because of mistakes in switching fuel flow controls, or because of contaminants in the fuel, or blockage in the supply lines. The second type is fuel exhaustion, when all usable fuel is expended.
There is good news and bad news about running out of gas. If we crash as a result of fuel exhaustion the chances of a post-crash fire are greatly reduced. Likewise, if we are forced to ditch in the water, the empty fuel tanks can enhance the buoyancy of the aircraft, giving us more time to get out. The bad news is that we are usually forced to land on some unprepared surface and we really tear the aircraft up.
A notable fact about fuel exhaustion accidents is that the pilot doing the flight planning is usually nearly perfect. They calculate their endurance very close to what actually occurs. A very high percentage of the accidents occurred within one mile of the destination airport. They only missed it by thaaaat much!
One reason pilots run out of gas is that they don't know how much they have - even when it is full. The pilot of a light twin planned a flight based on 182 gallons of full fuel. He arrived at his destination only to find it below minimums. He had to make a go-around, and shortly thereafter both engines quit. He landed 1 mile short of the runway and tore-up the airplane, but survived. The investigation reveled that his endurance was equal to the 162 gallons he actually had aboard, which was the real capacity of the airplane. That information was in the handbook as well as being placarded next to the fuel filler points.
I once gave an "unsat" to a pilot taking a checkride for not knowing where a stepladder was. He was taking the ride in a CE-182 at a facility where he had received all his training. He staggered his way through the pre-flight, obviously using the checklist for the first time. When it came time to check the fuel he suddenly realized that he was going to have to find some way to raise himself up to the top of the wing. Despite having trained in this airplane, he thought he might find a step in the baggage compartment. Of course there wasn't one there so he concluded a stepladder would be appropriate. Unfortunately, he had no idea where to find one. I asked him where he had found it on his previous flights, but he had no answer. After I told him the ride was unsat, I suggested we find his flight instructor and have him tell us where a ladder might be.
One pilot experienced fuel starvation, even though he knew how much fuel he had aboard and precisely how much he burned an hour. What he didn't know however, was that on the typical short flights he was making, all the fuel was coming out of one tank due to a blockage in the lines. The refueler never mentioned it because he assumed the pilot was running avgas in one tank and autofuel in the other, not an uncommon practice for aircraft certified for autofuel, and only burning out of one tank. The pilot was therefore confident when he planned his endurance for a long cross country, and shocked in disbelief when the engine quit ¾ of the way to his destination.
Pilots don't intend to have accidents. When they occur they are usually the consequence of human factors, not stupidity. Running out of gas however is almost stupid.
Balloon Instructor Clinic
Spectrum Balloon Port
8AM to 4PM
27th Super Safety Seminar
St Louis University
Lower level Cook Hall
Gateway Aerostatic Association Safety Seminar
Dave & Buster's Restaurant
Aviation Safety - Education Seminar
Ryan's Steak House
West Plains, MO
Greater St Louis Flight Instructors Flight Instructor Renewal Clinic - FIRC
LET'S NOT MEET BY ACCIDENT
FRED P. HARMS
Operations Safety Program Manager
1-800-322-8876 extension 4835