Toledo, OH, USA
N607QS
CESSNA 560XL
The Cessna 560XL airplane encountered ground and/or in-flight moisture/rain, that collected in the tailcone stinger and subsequently froze around the rudder cables during flight at an altitude above the freezing level. When the pilot attempted to use the rudder to initiate a crosswind correction during the landing flare, he was unable to move the rudder pedals, but was able to land the airplane uneventfully. In the days and weeks that followed, several other 560XL airplanes encountered the same problem. As a result, the airplane manufacturer issued a service bulletin recommending that drain holes be added in the tailcone stinger. The manufacturer had already added the drain holes in production airplanes, yet some production airplanes had drain holes that were not the indicated size. The manufacturer then issued an alert service letter to modify the stinger drain. However, the alert service letter still did not remedy the problem; another 560XL airplane, modified in accordance with the alert service letter, sustained ice-bound rudder cables. The manufacturer subsequently issued a mandatory service bulletin that required the installation of a seal and drain to improve water drainage from the stinger. The misdrilled holes on production airplanes were not detected by the Federal Aviation Administration (FAA) district office assigned to oversee the incident airplane. The manufacturer has subsequently instituted a specific inspection criteria to verify the drain hole installation on production airplanes, and the FAA has verified engineering requirements, planning changes for technicians to follow, and actual holes, including their dimensions.
On December 1, 2010, about 1336 eastern standard time, a Cessna 560XL, N607QS, operated by NetJets Aviation, Inc., sustained a loss of rudder authority when the airplane’s rudder bound during landing at the Toledo Express Airport (TOL), near Toledo, Ohio. The airplane landed without incident and was undamaged. The two pilots and one passenger were not injured. Visual meteorological conditions prevailed. The flight was operating on an activated instrument flight rules flight plan. The non-scheduled domestic passenger flight was conducted under 14 Code of Federal Regulations Part 135. The flight departed from the Monmouth Executive Airport (BLM), near Belmar, New Jersey, about 1159, and was destined for TOL. On November 29, 2010, according to the operator, the airplane had landed at the Philadelphia International Airport (PHL), Philadelphia, Pennsylvania, and was parked on the ramp for 30 hours. Light rain was reported during the time the airplane was parked at PHL. On November 30, 2010, the flightcrew repositioned the airplane from PHL to BLM where the airplane was parked under an open canopy. On the morning of December 1, 2011, the flightcrew performed a preflight inspection of the airplane at BLM and they noted that it was raining moderately during the preflight with a temperature of 15C. The flightcrew reportedly conducted a normal preflight inspection, which included an inspection of the control cables visible in the aft equipment bay where no discrepancies were noted. The aircraft was repositioned under the canopy facing into the wind for the engine start. The startup and taxi procedures, including a flight control check and rudder bias check were conducted. All checks were normal. The flight departed through light to moderate rain until west of the PHL airspace and the flight was subsequently cleared to climb to a cruising altitude of flight level 400. The cruise portion of the flight was at an altitude above the freezing level. The flight broke out on top of the cloud layer into clear skies during the climb about 14,000 feet above mean sea level (MSL). The remainder of the flight was in clear conditions until its descent through 8,000 feet MSL on approach to TOL. During the approach, the autopilot was disconnected while descending through 2,500 feet MSL. The flight broke out of the clouds about 1,600 feet MSL. The yaw damper was disconnected while descending through 600 feet above ground level. The recorded temperature at TOL was -2 degrees C at 1252. No problems were noted until the pilot flying attempted to use the rudder to initiate a crosswind correction during the landing flare. At that time, the flying pilot noted he was unable to move the rudder pedals. Other than the lack of rudder authority, the landing was uneventful. The airplane taxied to the ramp using differential thrust and braking. After arrival with the engines shut down, the flightcrew noted that the rudder pedals would still not move. They attempted to manually move the rudder and found that it would not move. Postflight examination of the airplane by maintenance personnel revealed that ice had accumulated in the tail cone stinger and it interfered with the rudder control cables and pulleys in the tail cone, which rendered the rudder immovable. On April 1, 2005, Cessna issued service letter (SL)560XL-53-05, which listed procedures including drilling a 0.201-inch hole that provided a drain path for moisture that accumulated within the stinger. SL560XL-53-05 applied to 560XL airplanes with serial numbers between 560-5002 and 560-5544. Airplanes with serial numbers higher than 560-5544 had their SL560XL-53-05 drain holes incorporated in the tailcone stinger during factory production. This incident airplane, serial number 560-5340, stinger’s tailcone assembly, part number 6612119-60, had a drain hole incorporated in it. However, a Federal Aviation Administration (FAA) inspector examined the airplane and found that its tailcone stinger had a 0.182-inch drain hole, which was smaller than the 0.201-inch drain hole dimension indicated in SL560XL-53-05. The FAA inspector was asked to examine other Cessna 560XL airplanes’ drain holes that were present in the maintenance hangar that housed N607QS in TOL. Three other Cessna 560XLs, with serial numbers 560-5305, 560-5548, and 560-5661, drain holes were smaller than the drain hole dimension indicated in SL560XL-53-05. The serial number 560-5548 and 560-5661 airplanes should have had correct dimensioned drain holes incorporated in their tailcone stingers during factory production. According to preliminary information supplied to the National Transportation Safety Board (NTSB), on December 13, 2010, a Cessna 560XL, N498AB, sustained no damage when the airplane’s rudder bound during landing at the Birmingham-Shuttlesworth International Airport, near Birmingham, Alabama. This incident investigation's report number is CEN11IA111. According to notification information supplied to the NTSB, on December 20, 2010, a Cessna 560XL, N626QS, sustained no damage when this airplane’s rudder also bound during landing at the Idaho Falls Regional Airport (IDA), near Idaho Falls, Idaho. Cessna issued alert service letter (ASL)560XL-53-08 on January 21, 2011. The ASL, in part, stated: REASON The stinger may not drain water which may allow ice to form around the rudder bias cable pulleys. DESCRIPTION This alert service letter provides instructions to inspect for drain holes in frames immediately forward and aft of access panel 321ABC, and drill them if necessary. Instructions are also provided to seal an existing drain hole in the tailcone stinger and add a drain hole in the aft canted bulkhead. COMPLIANCE MANDATORY. This alert service letter must be accomplished within 90 flight hours or 90 days from the date of receipt, whichever occurs first. On March 15, 2011, the NTSB issued Safety Recommendation A-11-16 to the FAA. A-11-16 recommended that the FAA issue an airworthiness directive to require that all Cessna 560XL operators comply with Cessna ASL560XL-53-08. According to preliminary information supplied to the NTSB, on March 10, 2011, while climbing through approximately 28,000 feet in the vicinity of Haynesville, Maryland, a Cessna 560XL, N588QS, operated by NetJets Aviation, Inc., experienced stuck rudder controls. N588QS was modified to comply with ASL560XL-53-08. This incident investigation's report number is ERA11IA184. Cessna subsequently issued service bulletin (SB)560XL-53-16 titled Fuselage – Stringer Drain Installation on October 4, 2011. SB560XL-53-16, in part, stated: EFFECTIVITY MODEL SERIAL NUMBERS 560XL (Citation Excel) -5002 thru -5372 560XL (Citation XLS) -5501 thru -5830 560XL (Citation XLS+) -6002 thru -6080, -6082 thru -6086 The equivalent of this service bulletin has been incorporated on production airplanes -6081 and -6087 and On. NOTE: For airplanes affected by ASL560XL-53-08, Fuselage - Aft Canted Bulkhead Drain Installation, that alert service letter must be complied prior to or in conjunction with this service bulletin. REASON To install a seal and drain to improve water drainage from the stinger. DESCRIPTION This service bulletin provides parts and instructions to install a drain and seal that will reduce the amount of water entering the stinger and improve drainage. SB560XL-53-16 listed a drain tube assembly as part of its required materials. The FAA’s Wichita Aircraft Certification Office (ACO) approved Cessna's issuance of ASL560XL-53-08 and SB560XL-53-16. On May 11 through May 19, 2011, the FAA's Wichita Manufacturing District Office (MIDO) and ACO conducted a district office audit to evaluate Cessna’s quality control data for compliance with FAA regulations. That audit did not detect any misdrilled tailcone stinger drain holes on production 560XL airplanes. Cessna subsequently instituted a specific inspection characteristic to verify the drain hole installation. A MIDO inspector conducted a follow-up inspection on August 16, 2011, verifying engineering requirements, planning changes for technicians to follow, and actual holes to include their dimensions. The inspector also verified the drain scupper installation on the first airplane in production to receive it. The drain scupper is listed as a "tube weld assembly" with part number 6612060-1 in SB560XL-53-16.
The manufacturer's inadequate initial design and subsequent modifications of the tailcone, which allowed moisture to collect and freeze around rudder cables during flight levels above the freezing level and resulted in a loss of rudder authority. Contributing to the accident was the lack of oversight of the manufacturer's design and production by the Federal Aviation Administration.
Source: NTSB Aviation Accident Database
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