Incident at Birmingham-Shuttlesworth International Airport
On December 13, 2010, about 0757 central standard time, a Cessna 560XL, registration N498AB, operated by Executive Jet Management, Inc., experienced a loss of rudder authority during landing at Birmingham-Shuttlesworth International Airport (BHM) near Birmingham, Alabama. The two pilots and one passenger were not injured, and the airplane was not damaged. Visual meteorological conditions prevailed. The flight was operating on an activated instrument flight rules flight plan under 14 Code of Federal Regulations Part 135 as a non-scheduled domestic passenger flight. It had departed Teterboro Airport (TEB) near Teterboro, New Jersey, about 0442, destined for BHM.
The operator reported that the entire flight was normal until the autopilot and yaw damper were disconnected on final approach. The flight crew found the rudder pedals unusually stiff, requiring brake steering during touchdown, rollout, and taxi to the parking ramp.
Maintenance personnel examined the space inside the airplane's tailcone stinger and found ice. The ice was removed, and the airplane was subsequently returned to service.
Service Letters and Earlier Incidents
Cessna had issued Service Letter (SL) 560XL-53-05 to provide a drain path for moisture accumulating within the tailcone stinger, applicable to serial numbers 560-5002 through 560-5544. Airplanes with higher serial numbers had the drain hole incorporated during production. The incident airplane, N498AB (serial number 560-5116), had a tailcone stinger assembly with a drain hole that complied with SL560XL-53-06 dimensions and location.
A similar incident occurred on December 1, 2010, involving a Cessna 560XL, N607QS, operated by NetJets Aviation, Inc., at Toledo Express Airport (TOL) near Toledo, Ohio. No damage or injuries occurred. Examination revealed ice in the tailcone stinger that interfered with rudder control cables and pulleys, rendering the rudder immovable. An FAA inspector found that the drain hole size on N607QS was smaller than the 0.201-inch hole specified in SL560XL-53-05. Inspection of three other Cessna 560XLs at the same hangar (serial numbers 560-5305, 560-5548, and 560-5661) also had drain holes smaller than specified. Two of these, 560-5548 and 560-5661, should have had correct-sized holes from production.
On December 20, 2010, another Cessna 560XL, N626QS, sustained rudder binding during landing at Idaho Falls Regional Airport (IDA) near Idaho Falls, Idaho, with no damage reported.
Alert Service Letter and Safety Recommendation
In response, Cessna issued Alert Service Letter (ASL) 560XL-53-08 on January 21, 2011. It stated that the stinger may not drain water, allowing ice to form around rudder bias cable pulleys. The ASL provided instructions to inspect for drain holes in frames forward and aft of access panel 321ABC, drill them if necessary, seal the existing drain hole in the tailcone stinger, and add a drain hole in the aft canted bulkhead. Compliance was mandatory within 90 flight hours or 90 days.
On March 15, 2011, the NTSB issued Safety Recommendation A-11-16 to the FAA, recommending an airworthiness directive to require compliance with ASL560XL-53-08.
Subsequent Incidents and Service Bulletin
On March 10, 2011, a Cessna 560XL, N588QS, operated by NetJets Aviation, experienced stuck rudder controls while climbing through approximately 28,000 feet near Haynesville, Maryland. This airplane had been modified per ASL560XL-53-08.
Cessna issued Service Bulletin (SB) 560XL-53-16 on October 4, 2011, titled "Fuselage – Stringer Drain Installation." It applied to Citation Excel serial numbers -5002 through -5372, Citation XLS -5501 through -5830, and Citation XLS+ -6002 through -6080 and -6082 through -6086. The bulletin aimed to install a seal and drain to improve water drainage from the stinger. It required prior or concurrent compliance with ASL560XL-53-08 for affected airplanes.
Regulatory Oversight
The FAA's Wichita Aircraft Certification Office approved ASL560XL-53-08 and SB560XL-53-16. From May 11 to May 19, 2011, the FAA conducted a district office audit of Cessna's quality control data, which did not detect misdrilled drain holes on production airplanes. Cessna then instituted a specific inspection characteristic. A follow-up inspection on August 16, 2011, verified engineering requirements and drain scupper installation per SB560XL-53-16.