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In the years since my student pilot days, it’s fair to say I’ve spent a good deal of time playing the Monday morning quarterback regarding flight instruction practices. This has been especially true since I earned my instructor ratings and began to build better mousetraps in earnest. I’ll be the first to admit that, in some instances, personal preference and a dash of ego serve to push my hindsight to a bionic level. However, I still believe that, in certain cases, a large portion of the flight training community is going about their instruction techniques in the wrong manner.

Tanker Refuel

Throughout my tenure as a flight-training student in a Part 141 university program, I often questioned the school’s unyielding insistence that all aircraft fuel tanks must be topped off before every leg of every cross-country flight. For the most part, I appreciated this while working on my private certificate. Later on, however, I encountered several situations in which I thought departing with a lighter fuel load actually made sense. Despite my suggestions, my instructors (and the school) insisted that I load up on fuel before launching on each segment.

A Brief Example

This afternoon, I grabbed an old sectional, plotter, E6-B flight computer (whiz wheel), and my Cessna 152 pilot’s information manual. I then set about determining an approximate fuel requirement for one segment of a three-leg cross-country from my student pilot days. For the leg in question, the departure and destination airports are a mere 25 nm from each other.

Figuring conservatively at an average groundspeed of 90 kts and using an (also conservative) average fuel burn of 6.0 gph, the numbers showed I’d be airborne for about 17 minutes; in which I’d burn approximately 1.7 gallons of 100LL. Although I didn’t go to the trouble of calculating time, fuel, & distance to climb/descend; after including startup/taxi fuel of (per Cessna) 0.8 gallons, it’s fair to say I could expect to burn about 3 gallons of fuel over the course of this leg. Since the 152 holds 24.5 gallons of usable fuel (standard tank configuration), why on earth would I need to refuel before launching on my final flight segment (57 nm) of this trip?

A Common Practice

Following my graduation from the university’s flight program, I secured a CFI position with a nearby Part 61 flight training provider. Although I was now free (and able to permit my students) to use less-than-full fuel tanks, we’d frequently encounter the full-tanks phenomenon from students visiting our airport on their solo cross-country flights. Two of the region’s universities (not my alma mater) sent their trainees our way and insisted they top off the tanks prior to heading back to base. I remember our line service technicians grumbling about this; claiming School X’s plane would take just 4.6 gallons, while University Y’s bird could accommodate a whopping 4.8 gals. In both cases, barring hurricane-force headwinds, these aircraft could easily have completed the return trip (a few times over) without getting anywhere near a critical (or legal) fuel status.

Part 61 Planning

Later on, I provided instrument training to the private owner of a single-engine, complex airplane.  Our flights usually took place during the student’s commute to a job site; which was often several states away. Wherever we landed, the individual always advised FBO personnel to “top ‘em off.” This person stated as much to me, claiming “I always just have them fill me up completely.” Despite my student’s evident satisfaction with having adopted this practice, (s)he even told me of the pain-in-the-neck experience of once having to offload several gallons of fuel in order to make weight for (seldom-carried) passengers. However, my trainee expressed no interest in avoiding future recurrences by actually calculating the requisite fuel load.

Why it’s a Poor Practice

Before I convince anyone that topping off the tanks is an evil deed, let me be perfectly clear that doing so sometimes makes a lot of sense. For example, if you know you’ll be traveling alone in a lightly loaded bird, filling up ahead of time can sometimes save you a fuel stop. Additionally, if you’re able to buy gas at a noticeably cheaper price than nearby airports are offering, you can end up coming out money ahead. Better yet, carrying additional fuel reduces the chances you’ll run the engine(s) dry and have to practice glider operations. However, these positive attributes are sometimes offset by the undesirable qualities of tankering too much fuel.

Negative Consequences of Hauling Unnecessary Gas

If your M.O. includes squeezing every possible drop of gas into your aircraft, consider some of the potential downsides of doing so:

  • Increased Runway Requirements: Whether departing or landing, a heavier bird will need more pavement than a lighter equivalent.
  • Reduced Rate of Climb: Depending on where/when you fly, this can be a significant factor. This is especially true for multiengine pilots; where a powerplant failure can substantially reduce (perhaps negate) the aircraft’s ability to climb and/or hold altitude. This is one of the primary reasons professional crews tend to avoid departing with full fuel (when practical).
  • Lower Useful Load: Every aircraft comes with a set of weight restrictions. In terms of useful load, each unnecessary pound of fuel aboard robs you of a pound of people or items that could otherwise be carried. This is particularly important in commercial ops, where the amount of passengers and cargo carried impacts the operation’s bottom line. Even if you’re able to haul the weight of full fuel tanks, the added ballast will negatively affect the aircraft’s overall performance capabilities (as mentioned above). Keep these factors in mind in your future fuel-planning decisions.

Who Establishes the Industry’s Training Practices?

In many ways, the aviation insurance industry has as much influence on flight operations as the government. This is doubtless a reason why many university (and private) operators insist on full-tanks operations. While this does theoretically reduce the likelihood of fuel starvation incidents, I’m convinced it encourages unsafe practices in other areas. For example, I believe the full-tank habit can lead to complacency, inadequate understanding of flight planning & performance, and reduced situational awareness. Besides, it’s not how the pros fly, so such training doesn’t do much to prepare students for real world flight ops.

Although I can’t do much to alter established flight school and insurance requirements, I can encourage each of you to give added consideration to your fuel planning practices. Remember, as pilot in command you’re ultimately responsible for the safety of your operations, so give your PIC position its due in your future fueling decisions.

Stephen Lewis, aka The  Write Flier, is an ATP, CFII, MEI, and  professional aviation  writer.

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