Mooney M20J N3700H accident near Marco Island, Florida

Probable cause

The pilot’s improper pitch trim setting before takeoff, which resulted in the airplane’s rapid, nose-high pitch at takeoff and the pilot’s subsequent loss of control.

NTSB analysis

The pilot stated that he set the flaps at 15 degrees for takeoff and that the flap position indicator and the adjacent pitch trim position indicator appeared to "line up," which was normal. However, during the takeoff, the airplane pitched up more rapidly than normal, and the pitch trim did not seem to be working. The event occurred too quickly for the pilot to abort the takeoff, and, because of the relatively low airspeed and the high engine torque and P-factor, he was unable to counteract the airplane's left turning tendency. The airplane subsequently descended into a swamp left of the runway.

At the accident scene, the airplane's flap and trim position annunciators indicated that the flaps were in the "takeoff" position but that the pitch trim was in the "up" position; the Pilot's Operating Handbook stated that the pitch trim was to be set to the "takeoff" position for takeoff. For pitch trim control, the airplane's entire empennage would have pivoted to increase or decrease the horizontal stabilizer angle. The system used a worm gear, which would have prevented the annunciated trim position from moving when the airplane impacted the ground. Pitch trim was subsequently tested electrically to the stops with no binding noted. The pilot did not report any runaway pitch anomalies.

Text from the NTSB. Open the NTSB docket for ERA13LA374 for the full record.