Narrative:

I departed...for a 1-hour flight. The flight was conducted on a completely clear and ideal day for flying. Weather was not a factor throughout this flight. I departed to the west and climbed to 3;000 ft MSL to perform some maneuvers. These included steep turns; slow flight; and stalls. I also performed a 'zero-G' maneuver where I setup for a power-off stall and; as the aircraft approaches stall speed; I pushed the controls forward to simulate a weightless effect. This was done purely for 'fun' purposes and I had checked beforehand with instructors at the FBO to make sure that the maneuver was safe. This was not the first time I had performed this maneuver. After this particular maneuver; however; I noticed that the trim wheel was tougher to turn. It had not moved on its own; but rather it felt tight. I noted the anomaly and returned to the airport for a normal landing and parking. I 'squawked' the issue; and reported it to the appropriate staff; not thinking much of it at the time. Two days later; I learned that the battery; which is stowed in the rear of the aircraft; had become dislodged from its position and battery acid had spilled over the control cables; thereby causing the firmness in the controls I had felt during flight. I learned that I must have gone beyond zero-G and into the negative-G regime; thereby causing the battery to become dislodged. Although I believed I had mitigated the risk surrounding the maneuver by researching it first and asking other flight instructors about it; I realize now that additional risk could have been reduced had I performed the maneuver with another instructor first. I shall not be performing this maneuver again in any form; and I believe it could use some more attention since many pilots don't seem to know the proper way to perform a 'zero-G' maneuver. The implications of an improperly performed zero-g maneuver are also not well publicized; either in the aircraft poh or general internet sources.

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Original NASA ASRS Text

Title: After attempting to demonstrate a Zero-G maneuver and possibly going into Negative-G regime; a PA-28R pilot noted that the elevator trim felt tight; but controls were otherwise normal. Maintenance personnel subsequently advised that the battery became dislodged and acid had spilled onto the control cables.

Narrative: I departed...for a 1-hour flight. The flight was conducted on a completely clear and ideal day for flying. Weather was not a factor throughout this flight. I departed to the west and climbed to 3;000 FT MSL to perform some maneuvers. These included steep turns; slow flight; and stalls. I also performed a 'zero-G' maneuver where I setup for a power-off stall and; as the aircraft approaches stall speed; I pushed the controls forward to simulate a weightless effect. This was done purely for 'fun' purposes and I had checked beforehand with instructors at the FBO to make sure that the maneuver was safe. This was not the first time I had performed this maneuver. After this particular maneuver; however; I noticed that the trim wheel was tougher to turn. It had not moved on its own; but rather it felt tight. I noted the anomaly and returned to the airport for a normal landing and parking. I 'squawked' the issue; and reported it to the appropriate staff; not thinking much of it at the time. Two days later; I learned that the battery; which is stowed in the rear of the aircraft; had become dislodged from its position and battery acid had spilled over the control cables; thereby causing the firmness in the controls I had felt during flight. I learned that I must have gone beyond zero-G and into the negative-G regime; thereby causing the battery to become dislodged. Although I believed I had mitigated the risk surrounding the maneuver by researching it first and asking other flight instructors about it; I realize now that additional risk could have been reduced had I performed the maneuver with another instructor first. I shall not be performing this maneuver again in any form; and I believe it could use some more attention since many pilots don't seem to know the proper way to perform a 'zero-G' maneuver. The implications of an improperly performed zero-g maneuver are also not well publicized; either in the aircraft POH or general internet sources.

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.