What happened
On December 1, 2010, a Cessna 560XL, registration N607QS, was on approach to Toledo Express Airport (TOL) in Ohio when the pilot experienced a loss of rudder authority. The flight, operated by NetJets Aviation, Inc., had departed from Monmouth Executive Airport (BL/BLM) under instrument flight rules.
Prior to the flight, the aircraft had been parked at Philadelphia International Airport (PHL) for 30 hours during which light rain occurred. On the morning of the accident, the flightcrew performed a preflight inspection in moderate rain at BLM. During the descent and approach to TOL, the aircraft transitioned through various altitudes, including levels above the freezing level.
As the pilot attempted to use the rudder to perform a crosswind correction during the landing flare, the rudder pedals became immovable. Despite the lack of rudder authority, the pilot landed the aircraft without incident. The aircraft was not damaged, and the two pilots and one passenger were not injured.
The investigation
Postflight inspections by maintenance personnel confirmed that the rudder pedals remained stuck. Investigators determined that ice had accumulated in the tailcone stinger, which interfered with the rudder control cables and pulleys.
An examination of the aircraft's tailcone stinger revealed that the drain hole, while present, measured only 0.182 inches, which was smaller than the 0.201-inch dimension required by Cessna service letter SL560XL-53-05. An FAA inspector found that three other Cessna 560XL aircraft in the same hangar also had undersized drain holes.
Subsequent investigations revealed that several other 560XL aircraft had experienced similar rudder binding incidents. While Cessna issued an alert service letter (ASL560XL-53-08) to address the issue, another aircraft experienced the same failure even after modifications. Eventually, Cessna issued service bulletin SB560XL-53-16, which required the installation of a seal and a drain tube assembly to improve drainage.