PA-28R Cherokee Arrow All Series
Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Commercial
Flight Crew Last 90 Days 8; Flight Crew Total 349; Flight Crew Type 44
Training / Qualification; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Aircraft Aircraft Damaged; General Maintenance Action
Aircraft; Equipment / Tooling; Procedure
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.
Reporter stated that after he was contacted by the FBO Maintenance Department about battery acid on the controls he recalled that the trim might have felt 'stiffer' to operate; but that the flight controls were otherwise normal. The reporter said that he did not inquire as to whether the battery and battery box were properly installed.
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.