Incident Description
On December 12, 2014, about 1300 central standard time, a Cessna model T182T, N93CL, experienced a flight control anomaly after takeoff. The airplane was performing a post-maintenance check flight under 14 CFR Part 91. The commercial pilot and a pilot-certificated passenger were on board. Visual meteorological conditions prevailed at the time. The airplane departed runway 12L at St. Louis Downtown Airport (CPS), Cahokia, Illinois, about 1250 for a local flight.
While at about 900 feet above ground level in the crosswind turn after takeoff, the airplane began to pitch steeply toward the ground, losing about 200 to 300 feet of altitude. The pilot applied extreme back pressure on the yoke to keep the nose level and confirmed the autopilot was not engaged. He asked the passenger for assistance pulling aft on the yoke, which required an estimated 150 pounds of force. The passenger made all radio calls and declared an emergency while the pilot maneuvered to land on runway 12R, the longest and widest runway available.
The pilot incrementally added nose-up elevator trim using the manual wheel, but the nose-down pressure did not ease. The trim wheel indicated full nose-up position. The passenger checked circuit breakers for any that could account for the problem but found none, and looked through the rear window to confirm no elevator damage; the empennage was undamaged. On base leg, the pilot applied nose-down trim using the electric trim on the yoke. The nose-down control forces lessened, and the pilot realized a control reversal had occurred. He performed a normal approach and landing without incident. Emergency response vehicles followed the airplane back to the hangar.
Maintenance Background
Maintenance records showed that a 100-hour/annual inspection had been performed, which included replacing the elevator trim actuator. The A&P mechanic who performed the maintenance reported installing the actuator, placing the two chains on the actuator sprockets, and verifying they were not crossed. He adjusted the turnbuckles to proper cable tensions. He moved the control wheel to full tab down and rigged to 15 degrees tab down, then to full tab up and adjusted to 24 degrees tab up from neutral. He verified the angles several times. A second A&P mechanic inspected the installation before closing panels, checking for foreign objects, cable safeties, cable runs, and smooth movement.
During the pilot's preflight, the A&P mechanic verbally briefed the pilot on all maintenance performed, specifically mentioning the elevator trim tab actuator replacement.
The Cessna Model 182 Maintenance Manual (Rev 18) provided instructions for removing and installing the elevator trim tab actuator. The trim tab control adjustment/test installation instructions included steps to move the control column to ensure elevators travel correctly and to ensure the trim tab moves correctly when operated by the trim wheel, with a note that nose-down trim corresponds to tab UP position.
The Cessna Model 182T owner's manual exterior inspection checklist included checking control surfaces for freedom of movement and security, and trim tab security.
Post-Incident Actions
Post-flight inspection of the elevator trim system revealed that moving the elevator trim wheel to the full down position resulted in the elevator trim tab moving to the down position.
As a result of the incident, the operator reported conducting two training sessions with maintenance personnel to review policies and procedures to ensure correct understanding and following of maintenance steps, including connecting flight controls and checking proper rigging. The operator also had an additional inspection panel installed on the right horizontal stabilizer's lower skin to provide a better view of the elevator trim cables, approved by the FAA.
The pilot-certificated passenger was on the check flight at the pilot's request to assist with crewmember duties, including running checklists, making radio calls, and helping check systems during the emergency, as well as assisting with pulling back on the yoke to relieve nose-down pressure. The pilot reported that the use of crew resource management (CRM) contributed to the successful outcome.
Title 14 CFR Part 91.407(b) states that no person may carry a person other than crewmembers in an aircraft that has been maintained in a manner that may have appreciably changed its flight characteristics until an appropriately rated pilot flies the aircraft and makes an operational check. 14 CFR 1.1 defines crewmember as a person assigned to perform a duty in flight.