Narrative:

Following takeoff on runway 30; engine power decreased accompanied by vibration. Immediately checked fuel pump; mixture; fuel valve; and ignition. Ignition key had fallen out and [I] could not locate [it]. Requested return to land. Runway 24 was closed and unusable. Was instructed right downwind number 2 behind aircraft on 4 mile final runway 30. Barely maintaining altitude; requested runway 24 and was reminded runway 24 notamed closed. Runway 24 was only option for on-airport landing so declared emergency and informed tower landing runway 24. Landed without incident. Key was located on floor after landing and ignition switch was found to be in an intermediate position between off and left mag. Child in right front seat apparently and unintentionally kicked the ignition switch out of position. Ground runs to full power and engine check indicated all engine parameters and conditions normal.

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Original NASA ASRS Text

Title: A child in a BE-35's right seat accidentally turned the ignition key off and knocked it out. After loosing power the pilot declared an emergency and returned to land on a closed runway.

Narrative: Following takeoff on Runway 30; engine power decreased accompanied by vibration. Immediately checked fuel pump; mixture; fuel valve; and ignition. Ignition key had fallen out and [I] could not locate [it]. Requested return to land. Runway 24 was closed and unusable. Was instructed right downwind number 2 behind aircraft on 4 mile final Runway 30. Barely maintaining altitude; requested Runway 24 and was reminded Runway 24 NOTAMed closed. Runway 24 was only option for on-airport landing so declared emergency and informed Tower landing Runway 24. Landed without incident. Key was located on floor after landing and ignition switch was found to be in an intermediate position between off and left mag. Child in right front seat apparently and unintentionally kicked the ignition switch out of position. Ground runs to full power and engine check indicated all engine parameters and conditions normal.

Data retrieved from NASA's ASRS site as of July 2013 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.