Poor Fuel Management
03-22-2010
I am the proud father of two wonderful children. I have a son which I am very proud of currently serving in the USMC and stationed across seas. He chose aviation as an area of service and is currently working on the helicopters. I also have a daughter which just turned 15 years old this past February. Just like most teens her age there is one major milestone on her mind, the automotive learner’s permit. After more then 25 years of driving some areas are you can say just 2nd nature to me but, when my daughter is behind the wheel I tend to be a little more apprehensive. I guess I can now understand how my flight instructor felt when he handed the yoke over to me for the 1st time.
Early on in my flight training an instructor once said to me “A new private pilot knows just enough to be dangerous, there’s a lot more to flying then just knowing how to land”.
One area of 2ndnature or rule of thumb if you will in aviation I hear pilots talking about is fuel management. Even I remember as a student pilot long before Duats or AOPA came along with there electronic flight planning program and I was being taught how to fill out a paper flight plan I was told to use a particular figure for the fuel burn on our Cessna 172 that I trained in.
Recently I attended a seminar entitled “Basic VFR flight planning” led by Matt Conway, Chief flight instructor with American Flyers in Atlanta, GA. Poor fuel calculations have claimed the lives of many people explains Matt, as pilots use the “Rule of thumb” to calculate fuel consumption for their flight. Not a good idea he said!
The round up figure may work for shorter flights but for longer cross country flights don’t take the chance. The Cessna Aircraft Co. recommends the following fuel calculation procedures. The following is an example of proper fuel calculations for the 1982 Cessna Skyhawk 172P.
Flight conditions:
Take off weight 2350 Pounds
Useable fuel 40 gallons
Temp 28º C
Field Pressure 1500 feet
Wind (along runway) 12 knot head wind
Distance 320 NM
Pressure alt 5500 Feet
Temp 20º C
Wind enroute 10 knot head wind
Power 66%
True air speed 112 knots
Cruise fuel flow 7.4 GPH
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Fuel to climb 1.6gal
Increase due to non standard temp 0.3gal
Corrected fuel to climb 1.9gal
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Total distance 320
Climb distance -12
Cruise distance 308
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(With 10 knot head wind)
True air speed 112
Wind speed -10
Actual speed 102
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308 Nautical Miles
102 Knots = 3.0 hours
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45 minute reserve 5.6 Gallon
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Engine start, Taxi, and take off 1.1
Climb 1.9
Cruise 22.2
Reserve 5.6
Total fuel required 30.8
Becoming relaxed in your preflight procedures can cost you more then time. Count the cost, spend the time and do it right regardless of your experience.
Tommy Eldridge
(source: 1981 Cessna POH for the Skyhawk 172P)
