Page 14 - March 2016

Fuel is one of
those absolutes
in aviation, like
altitude and airspeed,
that positively must be
maintained and managed
until the aircraft is parked.
It would seem simple
enough to keep sufficient
fuel in the tanks to enable
a planned landing. But,
several times a year,
some pilot somewhere
tries to fly with his
tanks contaminated by
air, with a less-than-
successful outcome. It’s
embarrassing to run out
of gas in a car, but it’s
more than embarrassing
in an airplane, when you
can’t just coast over to
the side and flag down
a passerby. Rather than
preach to the choir about checking for fuel quantity before departure and keeping plenty of reserves, let’s examine why people run dry and see how it can be prevented.
Three methods persist in bringing us to earth, when it comes to running out of fuel. The first, fuel exhaustion, is simply using up every drop of gas on board; there are no options, the airplane is now a glider and it must be steered to a landing of some sort. The second error, fuel starvation, means the pilot mismanaged the fuel supply, running empty on one tank and allowing himself to be forced down while there’s still fuel available somewhere onboard. Lastly, a fuel system failure is more rare, but it can happen, such as when a pump fails, a valve won’t function or a leak develops, rendering all or some of the fuel unavailable.
Ignorance
is as friendly as others they’ve flown. Moreover, the system behind the perceived simplicity is often quite complicated.
Amazingly, some pilots just don’t have a clue as to how their engines are supplied with the necessary fuel. Understanding one’s fuel system is crucial to longevity in this business, meaning that you need to know how many tanks there are, how they feed, and what it takes to get the fuel to the engines–lines, vents, pumps, valves and drains. Easy fuel management is a great asset for an airplane, but it’s important for pilots to know that not every airplane
12 • TWIN & TURBINE
MARCH 2016
Why Do Pilots M
Run Out Of Gas?
utilize automated, simplified fuel manage- ment procedures. This does not mean the fuel supply and delivery system is simple, just that it normally does not require pilot interaction. You must still understand its inner workings and how to recognize faults. You were given an overview of your plane’s plumbing during initial or differences
As an example of how important it is to understand the plumbing, Cessna’s older tip-tanked piston-powered twins had a convoluted fuel system that grew more complex over the years of production. Fuel is contained in as many as six tanks, which must be used in an exact order, with pumps on the engines, in the tanks and in the lines, some of which are activated on their own and some by pilot-actuated switches. The valving and gauging takes some study, and I guarantee you that running a tank dry once in a while is a given. Not studying a diagram of an old twin Cessna’s fuel system before flying it is a big mistake.
Another case of ignorance that leads to running out of fuel is guessing at the consumption rate. I never cease to be amazed at the pilots who actually base their decisions on simple rules of thumb, instead of the numbers derived by test pilots and placed in the airplane’s operations manual. Even those latter figures, however, need to be verified in your own operation. Yes, a fuel computer works off a super-accurate transducer in the line, but even it can be fooled by incorrect inputs from the crew, or erratic refueling, perhaps caused by a sloping ramp or an unfamiliar fueler.
by LeRoy Cook
training; review the layout periodically to maintain
your knowledge.
ost modern transport- category aircraft