Cessna 421 Safety Record

the fracture of the landing gear upper barrel due to fatigue cracking, caused by improper machining after the barrel was assembled during the manufacturing process, resulting in damage to the airplane.

Water contamination within the aircraft's landing gear hydraulic line(s) which froze and blocked the line(s) preventing extension of the right main gear. A factor was the below freezing environmental conditions which the aircraft was operating in prior to and during the approach and landing.

The improper installation by maintenance personnel of the push-pull rod assembly on the right elevator trim tab horn resulted in an in-flight separation of the right elevator trim tab.

The failure of the left main landing gear scissors washer during taxi for takeoff, and collapse of the left main landing gear. A factor in the accident was the failure of unknown maintenance personnel to comply with a manufacturers service letter concerning the scissors washers.

The inadequate installation of the right propeller by the mechanic for his failure to properly torque the eight nuts resulting in fatigue failure of the studs and separation of the right propeller during cruise flight. Findings in the investigation were 1) the mechanic who installed the right propeller used un-calibrated torque wrenches, and 2) the mechanic who installed the right propeller used an outdated Service Manual.

The collapse of the left main landing gear during the landing rollout for undetermined reasons, which resulted in the pilot's loss of directional control.

the elevator trim tab bolt backed out, allowing the trim tab to flutter, and destroy the elevator. The factors involved were improper annual inspection by the maintenance personnel, and the inadequate aircraft preflight done by the pilot.

the pilot's inadvertent activation of the number one throttle/power control. Factors were: the pilot left the cockpit unattended with the engines running and a wet ramp.

water contamination in the hydraulic system, which froze in the (right) main gear hydraulic actuator, and restricted movement of the (right) main gear retraction and extension system.

inoperative deicing equipment, due to multiple wing boot holes and malfunctioning control/shuttle valves; subsequent build-up of airframe (wing) ice; and failure of the pilot to maintain adequate airspeed during the flare for landing. Factors relating to the accident included: the adverse weather (icing) conditions, and inadequate maintenance concerning the deicing equipment.

the failure of the pilots of the Cessna 421B, N450SU, and the Cessna 152, N94532, to maintain visual lookout. Factors were: the inadequate radio communications maintained by both pilots, and the failure of the student pilot of the Cessna 152 to take evasive action.

the pilot's selection of a runway inappropriate for the tailwind condition and his resultant failure to achieve a touchdown point which would allow the aircraft to stop prior to over running the departure end. The rough condition of the dirt runway, the lack of lighted wind indicators, and the operator's failure to develop procedures for night operations at the airport are factors in the accident.

THE IMPROPER RIGGING OF THE LANDING GEAR SAFETY SQUAT SWITCH BY OTHER MAINTENANCE PERSONNEL. CONTRIBUTING TO THE ACCIDENT WAS THE CONTAMINATION OF THE GEAR SQUAT SWITCH WITH CORROSION AND WATER.