NTSB Factual Report

HISTORY OF FLIGHT

On September 26, 2005, about 0905 eastern daylight time, a Cessna 560XL, N699QS, piloted by an airline transport pilot, sustained substantial damage when the nose landing gear collapsed during taxi for takeoff at the Port Columbus International Airport, Columbus, Ohio. The 14 CFR Part 91 positioning flight was operating in visual meteorological conditions on an instrument flight rules flight plan. The flight crew was not injured. The flight was originating at the time the accident occurred.

AIRCRAFT INFORMATION

The airplane was a Cessna model 560XL, serial number 560-5199. The airplane was a pressurized monoplane powered by two Pratt and Whitney PW545A turbofan engines. The type certificate data sheet for the airplane listed a maximum certificated takeoff weight of 20,000 pounds. At the time of the accident, the airplane had accumulated a total of 3953.4 hours total time in service. The most recent inspection was conducted in accordance with an Approved Aircraft Inspection Program (AAIP) on August 15, 2005. The airplane had accumulated 115.5 hours since that inspection.

WRECKAGE AND IMPACT INFORMATION

The airplane sustained damage to the fuselage that included a puncture of a pressurized section adjacent to an external mounted antenna. The airplane was removed from the taxiway by jacking the nose section off of the ground at which time the nose landing gear was reportedly blown down. The airplane's nose landing gear actuator was removed for further examination. A replacement nose landing gear actuator was installed and the airplane was ferried to the Cessna Aircraft Service Center in Wichita, Kansas, for repairs.

TESTS AND RESEARCH

While at the Cessna Aircraft Service Center for repair, the airplane's hydraulic and electrical systems were functionally tested with the replacement nose landing gear actuator installed. No anomalies were detected during the functional testing of either the hydraulic, or electrical systems associated with the operation of the nose landing gear.

According to maintenance records, the nose landing gear actuator that was on the airplane at the time of the accident, Cessna part number 9912491-3, serial number 0174, had been installed on the accident airplane on March 4, 2003. The airplane had accumulated a total of 1,429.3 hours time in service when that actuator was installed. The maintenance records indicate that this unit had been repaired and tested by the manufacturer prior to installation on the accident airplane.

The nose landing gear actuator that was on the airplane during the mishap was functionally tested and subsequently disassembled. The functional testing revealed that the nose landing gear lock indication switch behavior was erratic. The two poles of the switch did not change state simultaneously as expected. This switch is used to indicate the down and locked status of the nose landing gear. It was reported that the switch is used only for indication and has no effect on the physical operation of the actuator. No other anomalous behavior was detected during the functional testing of the actuator.

Subsequent to the functional tests, the nose landing gear actuator was disassembled. No anomalies were detected during the disassembly. The actuator manufacturer then checked the actuator components for dimensional accuracy. All measurements and part finishes were reported to be within specifications except for a finish on the "Ram Lock". There was no indication that this discrepancy would lead to an unintended retraction of the nose landing gear.

ADDITIONAL INFORMATION

The Federal Aviation Administration, Cessna Aircraft Company, and Netjets, Inc. were parties to the investigation.

NTSB Probable Cause

The collapse of the nose landing gear for undetermined reasons.