When fuel starvation happens in flight, it usually happens at the worst possible time..

And while you may not have caused the problem directly, there's a lot you can do to prevent it.

The following report is a perfect example:

The pilot stated he had an uneventful cross-country flight and on the downwind leg of the destination airport traffic pattern, he switched the fuel selector from the right tank to the left tank and turned on the boost pump. While on short final approach, the engine started losing power as the airplane was approximately 75 feet above ground level. The airplane subsequently impacted terrain about 600 feet short of the runway and came to rest upright. The pilot further stated that at the time of the engine power loss, he pushed all the controls, mixture, propeller, and throttle full forward and the engine rpm started to increase, but then quickly decreased again. The pilot then shut-off the master switch and walked to the fixed based operator to get help. He then walked back to the airplane, shut the ignition off and took his keys and headset out of the airplane. The pilot added that he did not touch the fuel selector.

Examination of the wreckage by a Federal Aviation Administration inspector revealed damage to the wings, landing gear, and stabilator. The inspector also noted that although adequate fuel remained in both fuel tanks, the airplane fuel selector was in the "off" position. The pilot further reported that there were no preimpact mechanical malfunctions with the airplane.

Follow The Checklist, Unless...

Checklists are ingrained in our flying. And at some point, all of us have found ourselves moving through checklist items almost automatically, which is how an empty fuel tank gets selected, or the fuel selector gets turned to the "off" position.

No one looks at the fuel selector in flight and says "hey, let's turn that off!" You're working the checklist, or that little GPS scheduler message pops up and says "switch fuel", and you do, without even thinking about it.

Look, Change, Wait

The first step to executing a checklist is to make sure the time is right. Look inside, look outside, and make sure you're ready to run the checklist.

When you decide it's the right time to switch tanks, there's a great rule-of-thumb to follow. When you change tanks or turn off a fuel pump, monitor your engine for thirty seconds.

Look, change, and wait. Make sure the fuel flow is steady, and the engine's running smooth. If it's not, undo what you just did.

The fuel selector is often your point of failure.

• 1) You select a bad tank. Either an empty one or one that's contaminated.
• 2) The valve fails and you can't feed from the tank.
• 3) You keep burning a tank until it's empty.
• 4) You don't move the selector all the way over to a tank, or you inadvertently select the off position.

This goes back to our earlier rule about changing the fuel system. Don't do it unless you have lots of time to restart the engine.

Upwind? Not a great time. The beginning of downwind? Also not a great time.

Change Tanks At The Right Time, Not Just Because Your Checklists Says So

There are a lot of issues that can cause fuel starvation. Broken lines and clogged filters are just a few reasons. Those can be hard to diagnose, and may not be solvable in-flight.

But most of the time, fuel starvation is caused by something we do to ourselves. Forgetting to switch tanks, or changing to a bad fuel system configuration are two of the most common reasons.

If you take one thing away from this, it's that you never want to reconfigure the fuel system out of habit. Always look, and make sure you're selecting a tank or setting that has fuel. Then after you make the change, wait. Make sure that your fuel flow and engine operation remain steady, and if it doesn't, undo what you just did.

The best way to prevent an emergency is to avoid touching the fuel system unless you have time and altitude to fix the problem.