What happened
On December 24, 2017, a Cessna 340, registration N247AT, crashed after departing Bartow Municipal Airport (BOW) in Bartow, Florida. The flight was operating under instrument flight rules (IFR) with a planned destination of Key West International Airport.
At the time of the accident, the area was experiencing dense fog with visibility less than 1/4 mile and an overcast ceiling of 300 feet. Due to the low visibility, the pilot requested that the aircraft be towed from its hangar to the ramp to avoid obstacles during taxiing. Witnesses at the airport reported hearing the engines performing a run-up and subsequently heard the aircraft take off. While the engines sounded powerful during the takeoff roll, witnesses could not visually confirm the aircraft's path due to the fog. Shortly after takeoff, an explosion was heard near the end of runway 9L, and the aircraft was found on fire.
The accident resulted in 5 fatal injuries, as the pilot and all four passengers perished in the crash. The aircraft was destroyed.
The investigation
Investigators examined the wreckage and found the debris path was approximately 230 feet long, oriented northeast. The impact pattern was consistent with the airplane rolling left over the departure end of the runway and striking the ground in a nearly vertical, nose-low attitude.
Mechanical examinations of the engines showed signatures consistent with the engines being at takeoff power at the time of impact. While the aircraft had a known issue where the autopilot could command full nose-down trim if engaged on the ground, investigators could not determine the status of the autopilot during the takeoff. The elevator trim actuator was found extended beyond its full travel limits, and the trim cable showed signs of tension overload.
Weight and balance calculations revealed that the aircraft was approximately 105 lbs over its maximum takeoff weight. This excess weight placed the aircraft outside of its center of gravity moment envelope, which likely increased the required takeoff roll and decreased the climb rate.
Additionally, maintenance records showed that the most recent IFR certification for the transponder and pitot-static system had been completed in June 2014, which was beyond the required 24-month interval. A discrepancy was also noted regarding engine oil changes; while logbooks indicated changes had occurred in 2017, the oil filters found at the scene were dated from 2014.