NTSB Factual Report

On August 9, 2005, at 1815 mountain daylight time, a Cessna 210, N9408T, piloted by a private pilot, received substantial damage on impact with runway 23 during a gear-up landing at Rapid City Regional Airport (RAP), Rapid City, South Dakota. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 personal flight was not operating on a flight plan. The flight originated from the Richard I. Bong Airport, Superior, Wisconsin, at 1520 central daylight time and was en route to RAP.

The pilot stated that during the approach to RAP, he noticed that the main landing gear did not extend. He notified air traffic control of the situation and then remained east of the airport for approximately 15 or 20 minutes attempting to lower the landing gear by following the emergency procedures in the airplane's Pilot Operating Handbook.

The pilot-rated passenger stated that when the landing gear was extended, the landing gear position indicator light did not illuminate. While attempting to lower the landing gear using the emergency landing gear pump handle, there was no pressure in the handle. During the landing, the airplane slid off the runway and onto grass.

According to the Federal Aviation Administration (FAA), the pilot could not extend the main landing gear and hydraulically actuated flaps, which resulted in a no flap landing on runway 23 (3,601 feet by 75 feet, asphalt).

The 1960 Cessna 210, serial number 57208, airplane was registered on July 12, 2005, to a corporation in which the pilot and pilot-rated passenger were principals. On October 26, 2004, the airplane was last inspected during an annual inspection at a total time of 2,799.3 hours and a tachometer time of 628.8 hours. On April 4, 2005, the airplane was repaired following a gear-up landing incident at a tachometer time of 663.0 hours due to, according to the pilot, interference from a frame mounted fuel pump that would not allow the nose landing gear to unlock. At the time of the accident, the airplane accumulated a total time of 2,840.2 hours, a tachometer time of 669.7 hours, and a Hobbs time of 1,057.7 hours.

The airplane was powered by a Continental IO-470-E-13, serial number 88678-71-E-R, engine, which was removed from the airplane on April 4, 2005 for teardown and inspection due to a propeller strike. The engine was repaired and inspected on May 18, 2005, at total time of 396.4 hours and reinstalled on June 29, 2005, at a tachometer time of 664.8 hours.

The on-scene inspection of the airplane, performed by the FAA, found a fractured hydraulic line in the nose section of the airplane.

The National Transportation Safety Board's Materials Laboratory examination of the hydraulic tube assembly included the main portion of the tube, the fractured flared end of the tube, attachment nut, and one of the ferrules. The tube assembly fractured at the transition between the tube portion and flared portion. Bench binocular microscope examination of the tube revealed the exterior surface at each end of the tube contained fourteen circumferential impressions. The fracture intersected the impression closest to the end of the tube.

The fracture features on the mating fracture faces for the most part were obliterated as a result of motion between the fractures. The origin area of a portion of the fracture was oriented 90 degrees relative to length of the tube portion. The remainder of the fracture was offset from 90 degrees. A portion of the fracture face in the area showed evidence of a barely visible crack arrest mark consistent with fatigue. The origin of the crack was not located at the metal squeeze-out areas. At the fracture location, the internal wall of the ferrule showed no evidence of wear, corrosion, or other type of deterioration. The attachment nut of ferrule showed no evidence of a crack. The length of the tube measured approximately 27.5 inches. The clamp marks were located at approximately 8.3 inches, 14.5 inches, and 21 inches from the fractured end of the tube.

The FAA and the pilot stated that there was no record of repair of the subject hydraulic tube assembly in the airplane maintenance logbooks.

NTSB Probable Cause

The landing gear extension not possible and inoperative flap system due to fatigue failure of a hydraulic system tube during approach. An additional cause was the improper rebuild/remanufacture of the hydraulic tube. Contributing factors were the dependency of the landing gear and flap systems on the common hydraulic system allowing a single-point failure to affect both systems.