NTSB Factual Report

On December 12, 2014, about 1300 central standard time, a Cessna model T182T, N93CL, experienced a flight control anomaly after takeoff, and an emergency landing was performed to the St. Louis Downtown Airport (CPS), Cahokia, Illinois. The commercial pilot and the pilot-certificated passenger were not injured, and the airplane was not damaged. The airplane was registered to and operated by CCL Aircraft LLC under the provisions of the 14 Code of Federal Aviation Regulations (CFR) Part 91 as a post-maintenance check flight. Visual meteorological conditions prevailed at the time of the incident. The airplane departed runway 12L at CPS about 1250 on a local flight.

The pilot reported that the airplane was about 900 feet above ground level in the crosswind turn after takeoff when the airplane "began to pitch steeply toward the ground." The airplane lost about 200 to 300 feet in altitude. He pulled hard aft on the yoke to keep the nose level, and he confirmed that the autopilot was not engaged. He called for the pilot-certificated passenger to assist him in pulling aft on the yoke which required "extreme back pressure." The pilot estimated that it took about 150 pounds of force to keep the airplane level. The pilot-certificated passenger made all the radio calls during the flight and declared an emergency while the pilot maneuvered the airplane to land on runway 12R, since it was the longest and widest runway available. During the flight, the pilot incrementally added nose-up elevator trim in an effort to relieve the nose-down pressure, but without effect. The manual elevator trim wheel indicated that the trim was in the full nose-up trim position. The pilot-certificated passenger checked the circuit breakers for any circuit breaker that could account for the problem, but there was none. He looked through the airplane's rear window to see if there was any impact damage to the elevator and confirmed that there was no damage to the empennage. The pilot turned onto the base leg still unable to relieve the "extremely strong" nose-down tendency. Both pilots were concerned that they would not be able to flare the airplane during landing, and that the airplane would contact the runway in an abnormal nose-down attitude. The pilot remembered that work had been done on the elevator trim system and thought that there might be some kind of control-reversal problem. While on the base leg of the approach, the pilot decided to apply nose-down trim using the electric trim on the control yoke. The nose-down control forces lessened, and he immediately realized that there was a control reversal. The pilot proceeded to make a normal approach and land at CPS without incident. The emergency response vehicles followed the airplane back to the hangar.

The post-flight check of the airplane's elevator trim system revealed that moving the airplane's elevator trim wheel to the full down position resulted in the elevator trim tab moving to the down position.

Maintenance records indicated that a 100-hour/annual inspection had been performed, which included replacing the elevator trim actuator. The airframe and powerplant (A&P) mechanic who performed the maintenance reported that he installed the trim actuator, placed the two chains on the actuator sprockets, and verified they were not crossed. He adjusted the turnbuckles to the proper cable tensions. He reported that he moved the elevator trim tab control wheel to the full tab down position and "rigged to 15-degrees tab down." He then moved the elevator trim tab control wheel to the full tab up position and adjusted the tab to "24-degrees tab up from neutral." He verified the up and down angle several times. A second A&P mechanic inspected the trim tab actuator installation before the inspection panels were closed by visually checking for foreign objects, cable safeties, cable runs, and smooth movement of the cables.

During the pilot's preflight of the airplane, the A&P mechanic who performed the installation verbally briefed the pilot on all the maintenance that was performed, specifically mentioning that he had changed the elevator trim tab actuator.

The Cessna Model 182 Maintenance Manual (Rev 18) provided the instructions for removing and installing the elevator trim tab actuator. The Trim Tab Control Adjustment/Test installation instructions included the following information:

(13) Move the control column to make sure that the elevators travel in the correct direction.

(14) Make sure that the trim tab moves in the correct direction when it is operated by the trim wheel.

NOTE: Nose down trim corresponds to the tab UP position.

The Cessna Model 182T owner's manual checklist for the exterior inspection of the empennage during preflight provided the following information:

1. Rudder Gust Lock (if installed) – REMOVE.

2. Tale Tie-Down – DISCONNECT.

3. Control Surfaces – CHECK freedom of movement and security.

4. Trim Tab – CHECK security.

5. Antennas – CHECK for security of attachment and general condition.

As a result of the airplane incident, the operator reported that two training sessions were conducted with maintenance personnel to review policies and procedures to ensure all steps are understood and correctly followed when performing maintenance on aircraft, including connecting flight controls and checking for proper rigging.

The operator had an additional inspection panel installed on the airplane's right horizontal stabilizer's lower skin to provide a better view of the elevator trim cables. The inspection panel installation was approved by the Federal Aviation Administration.

The pilot-certificated passenger was on the post-maintenance check flight at the request of the pilot to assist with crewmember duties. The pilot-certificated passenger assisted the pilot by running the checklists using a challenge and response to the checklist items, making all the radio calls to the air traffic controllers, and helping check the airplane's systems when the emergency occurred. He also assisted the pilot by pulling back on the airplane's yoke, relieving some of the extreme nose-down pressure felt by the pilot. The pilot reported that it was his opinion that the principles of crew resource management (CRM) used during the flight contributed significantly its successful outcome.

Title 14 CFR Part 91.407 (b) states, "No person may carry an person (other than crewmembers) in an aircraft that has been maintained, rebuilt, or altered in a manner that may have appreciably changed its flight characteristics or substantially affected its operation in flight until an appropriately rated pilot with at least a private pilot certificate flies the aircraft, makes an operational check of the maintenance performed or alteration made, and logs the flight in aircraft records." Title 14 CFR 1.1 defines "crewmember" as "a person assigned to perform a duty in an aircraft during flight time."

NTSB Probable Cause

The mechanic’s improper installation of the elevator trim actuator, which resulted in reversed elevator trim control, and his subsequent failure to detect the misrigging of the elevator cables during the postmaintenance inspection.