Aviation Safety Corner


GREETINGS! For this month's topic, I would like to continue discussing "Gasping For Gas." Many fuel exhaustion accidents share three common mistakes. This is Part II of IV.

Now, let's discuss "M" Number 3. MECHANICAL problems cause their share of fuel starvation accidents. Unfortunately for most pilots, the situations caused by mechanical failures were neither terribly unusual nor totally unexpected.

Leaking fuel drains repeatedly appeared as the culprits in dozens of accidents. More often than not, the pilots had been aware of the problems. Inaccurate or almost totally inoperative fuel gauges took their share of the blame, along with the pilots who knew of the existing conditions long before their final flights ever took place. In a more unusual situation, a fuel bladder partially collapsed, causing the pilot to see what he thought was more fuel than actually existed during his visual inspection of the tank.

But regardless of the particular malfunction that led each pilot to land short of the intended destination, each generally had a strong indication that all was not as it was supposed to have been. A pilot all know that running out of fuel is bad. They certainly realize that the engine stopping can lead to tragic results. The questions are obvious: Why do so many run out of fuel, and what can be done to avoid the tragedy that lurks there? The answer is surprisingly simple: Pilots who use bad judgment shouldn't do that anymore. The problem is that the simple answer hasn't fixed the problem. For reasons that too often defy explanation, pilots continue to run out of fuel.
Now, let's discuss, "Gauging the Answer." One school of thought is that, from the very beginning of a pilot's training, the proper emphasis is never put on fuel-related issues, and there are many. The complexities begin to appear with something as a fuel gauge.

FAR 23.1337(b) requires there to be "a means to indicate to the flight crew members the quantity of fuel in each tank during flight." Yet subparagraph (1) states, "Each fuel quantity indicator must be calibrated to read 'zero' during level flight when the quantity of fuel remaining in the tank is equal to the unusable fuel supply determined under FAR 23.959. "In short, the only time a fuel gauge must be accurate is when there is nothing left to use.
If you bet your life on the accuracy of the gauges anywhere between full and empty, the odds are good you will lose. But the history most pilots bring to flying encourages them to do just that. The history is the automobile. Who has not driven 10, 20 or 30 miles with the gas gauge needle pegged on empty, only to arrive at the gas station in time to "filler up'? In report after report, pilots did the same thing in their airplanes.

They knowingly over flew at least one or two airports on their way to an off-airport landing, just knowing that the fuel gauges weren't going to really be empty as soon as they showed E. The accuracy of "E" on the fuel gauge runs counter to an otherwise built-in forgiving nature and margin-for-error design of today's General Aviation Fleet, making it easy to understand how pilots can lead themselves to believe the worst is not yet to come.
Why else would a pilot 1) depart with one tank empty and the other indicating ¼ full or, 2) depart with "enough" fuel to fly 50 NM but only make it 30 NM? Pilots, it seems, have not only come to expect reliability from modern machines, but foolishly depend upon it. Gauges aren't the only error-prone part of the fuel system. Often pilots demonstrate a marked ignorance of how the fuel system components work together to ensure that the engine continues to run.

In one incident, a pilot who had been doing aerial survey work started to spiral down for a return to the airport when the engine promptly quit. Among his efforts to restart the engine was turning on the boost pump. The engine momentarily restarted, then quit again. Later investigation revealed that uncoordinated flight may have displaced fuel in the tanks away from the uptake line, and the boost pump most likely flooded the engine. What works in one airplane under certain circumstances doesn't necessarily work in another or even in the same aircraft under different circumstances. Properly learning the differences are essential to accurate fuel management.

Now in conclusion, REMEMBER, RUNNING OUT OF FUEL MAY BE THE CAUSE LISTED ON THE ACCIDENT REPORT, BUT LACK OF ADEQUATE KNOWLEDGE IS THE REAL REASON BEHIND THE PROBLEM. SAFETY TIP: REMEMBER, THE METHODS AND INFORMATION TO ELIMINATE ALMOST ALL THE ENTIRE FUEL STARVATION ACCIDENTS ARE AVAILABLE. IT STARTS AT THE BEGINNING OF A PILOT'S TRAINING, BUT THE LEARNING PROCESS SHOULD GO ON INDEFINITELY.
Don't miss next month's issue, "GASPING FOR GAS." Many fuel exhaustion accidents share three common mistakes. We will discuss, "LEARNING THE LESSONS, AND KNOWING WHEN TO QUIT" in Part III of IV.
See you at this month's chapter meeting! Bring a friend along! SAFE FLYING!

Larry G. Harmon

FAA AVIATION SAFETY COUNSELOR

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