Date: 201203
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Bonanza 33
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Takeoff / Launch
ATC / advisory: CTAF ZZZ
Aircraft component: Pilot Seat
Component problem: Malfunctioning
Reporter organization: Personal
Reporter function: Single Pilot
Reporter qualification: Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Inflight Event / Encounter Loss Of Aircraft Control
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; Flight Crew Regained Aircraft Control; Flight Crew Landed As Precaution; General Maintenance Action
Contributing factors: Human Factors; Aircraft; Procedure
Primary problem: Procedure

Narrative: [My] privately owned aircraft had been undergoing paint/upholstery refurbishment for over 30 days. I was picking up the aircraft to return to home station and was the sole occupant. I planned to get three landings for currency en route to home station. After topping off the fuel I was performing a normal takeoff. At rotation; the pilot's seat separated from its support and abruptly fell into the area between the front and back seats. The seat moved aft about 18-24 inches and rotated to a 20 to 30 degree reclined position. Since I was holding the yoke; it initially moved aft and the aircraft pitched up. Contributing to the pitch up were the trim (set for takeoff) and the aft shift in CG due to my falling backwards. I was faced with a situation where I had no ground references (the windscreen was full of sky) and the sensation that the aircraft was very nose high and slow. I kept my left hand on the yoke and tried to maintain wings level. It was impossible to exert forward movement on the yoke due to my limited reach from the seat. I had no rudder input for the duration of this event as my feet couldn't reach the pedals. The throttle remained at takeoff power. The aircraft had electric trim and I held nose down trim input throughout the recovery. I attempted to maneuver the seat back into position but had no success. I perceived the aircraft was near a stall.Finally; I was able to reach the glare shield with my right hand and pulled myself forward while pushing the yoke with my left hand. That finally allowed sufficient control movement to lower the nose. When I could see over the nose; I discovered I was several hundred feet left and about 2/3 of the way down the 4;000 FT runway. I estimate that the aircraft was 200 to 300 FT above the ground at recovery. I climbed; assessed the situation and flew to my mechanic's field which was nearby. The landing was without incident. Cause: The pilot's seat had been removed for upholstery work and was not properly reinstalled. The seat is mounted on two rails. Only the right rail has a stop at the back to limit aft movement of the manual seat adjust feature. When the seat was reinstalled; only the left rail was engaged in the track; the right rail was resting on top of its track. The event occurred just as the pitch angle changed at rotation and the there was nothing to limit the seat movement aft. Although I now know what to look for in this area; a seat inspection was not part of my regular preflight routine nor is it on any POH pilot checklist. I have extensive experience as a military fighter pilot and have experienced marginal control situations many times. In addition; I like training and have performed frequent power-on and other type stalls in this aircraft as a part of maintaining currency. When the event occurred; the focus of my efforts was to get the nose down; and keep the wings level. In the situation where I could not see the ground; I found myself keeping track of the only roll reference I had; a contrail - and tried to keep that stable. It did not occur to me to look at the attitude indicator. As far as pitch was concerned; I described my efforts to lower the nose using trim and leverage. I never looked at the airspeed indicator after starting the rotation at 70 kts. I knew from my stall practice that there would be good seat of the pants cues for the stall.




Synopsis: A BE33 pilot momentarily lost control and the aircraft pitched up abruptly during takeoff when the seat moved aft and off of its tracks. Through extraorinary effort he was able to regain control and proceed to a safe landing. The cause was the failure of maintenance personnel to reinstall the seat on both tracks following refurbishment of the upholstery.