Narrative:

During a student pilot training flight on jan/xa/09 at around XA40 pilot monitoring; my student and I experienced an engine failure due to fuel starvation. We were conducting a training flight in the ZZZ airport traffic pattern for runway xx. After 4 landings/takeoffs; my student switched from the right fuel tank to the left fuel tank. The fuel selector detent/lock did not restrict the selector from turning to the 'off' position as designed. Although I normally confirm the fuel selector is in the correct position visually during the change of tanks; I did not this time. During our 5th takeoff and climb; our engine suddenly failed momentarily; and ran very rough following. The engine failure occurred at roughly 500-600 ft AGL. This failure due to fuel starvation was the result of the fuel selector switch being placed about 1 inch to the left of the left tank which is toward the 'off' position. Normally; the detent/lock prevents this situation; however; the lock malfunctioned and allowed the fuel selector switch to move toward the 'off' position unrestricted. This was confirmed by the ZZZ maintenance department and I was told to squawk the item for repair. I declared an emergency immediately to ZZZ tower and landed opposite direction of current traffic on runway X uneventfully. Clearance and priority were given by ZZZ tower to land on any runway appropriate. Due to there being an uneven/mountainous terrain to the east of the airport and only partial power loss of the engine; I decided this was the best course of action. In the future; I will check and double-check the position of the fuel selector and have my students announce any movement of it verbally to avoid this from happening again.

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Original NASA ASRS Text

Title: A PA28 instructor pilot and his student experienced engine failure due to a defective fuel selector valve that failed to stop movement beyond the detent; shutting off the fuel supply.

Narrative: During a student pilot training flight on Jan/XA/09 at around XA40 pilot monitoring; my student and I experienced an engine failure due to fuel starvation. We were conducting a training flight in the ZZZ airport traffic pattern for Runway XX. After 4 landings/takeoffs; my student switched from the right fuel tank to the left fuel tank. The fuel selector detent/lock did not restrict the selector from turning to the 'off' position as designed. Although I normally confirm the fuel selector is in the correct position visually during the change of tanks; I did not this time. During our 5th takeoff and climb; our engine suddenly failed momentarily; and ran very rough following. The engine failure occurred at roughly 500-600 FT AGL. This failure due to fuel starvation was the result of the fuel selector switch being placed about 1 inch to the left of the left tank which is toward the 'off' position. Normally; the detent/lock prevents this situation; however; the lock malfunctioned and allowed the fuel selector switch to move toward the 'off' position unrestricted. This was confirmed by the ZZZ Maintenance Department and I was told to squawk the item for repair. I declared an emergency immediately to ZZZ Tower and landed opposite direction of current traffic on Runway X uneventfully. Clearance and priority were given by ZZZ Tower to land on any runway appropriate. Due to there being an uneven/mountainous terrain to the east of the airport and only partial power loss of the engine; I decided this was the best course of action. In the future; I will check and double-check the position of the fuel selector and have my students announce any movement of it verbally to avoid this from happening again.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.