Incident Overview
On December 2, 2011, at approximately 1228 eastern daylight time, a Cessna 560XL, registration N576CS, experienced an in-flight pitch trim malfunction while near Ocoee, Florida. The aircraft subsequently landed at Orlando International Airport (MCO) in Orlando, Florida. The flight was operated by CitationShares Management LLC under 14 Code of Federal Regulations Part 135 as an on-demand air taxi flight. The aircraft was registered to CitationShares Sales, Inc. Visual meteorological conditions prevailed and an instrument flight rules flight plan was filed. The flight originated at Naples Municipal Airport, Naples, Florida, at 1150 and was destined for Washington Dulles International Airport, Dulles, Virginia.
Flight Crew Actions
The flight crew reported that while approaching their level off altitude of flight level 410, a "Pitch Trim Miscompare" message illuminated in the cockpit. After completing the checklist items and disconnecting the autopilot, considerable forward yoke pressure was required to maintain level flight. The crew found the manual pitch trim control wheel to be "frozen" in the forward position and were unable to move it. The crew declared an emergency and diverted to MCO. During the descent for landing, upon reaching 8,000 feet mean sea level, the trim wheel released and the system returned to normal. The crew cancelled the emergency and landed at MCO without further incident.
Maintenance Findings
After the aircraft was secured, maintenance personnel inspected the flight control system. The grease in the left and right elevator trim actuators was found to be contaminated with water. The trim actuators were replaced and the airplane was returned to service. According to the operator, the elevator trim actuators were last inspected and lubricated 562 hours prior to the incident. The inspection requirement for the actuators was at 2,400 hours initially and at 1,200-hour intervals thereafter.