NTSB Factual Report

On April 6, 2005, about 1435 Alaska daylight time, a twin-engine Britten-Norman BN-2A Islander airplane, N29884, sustained substantial damage following a main landing gear component failure and subsequent loss of control while landing at the Klawock Airport, Klawock, Alaska. The flight was conducted under Title 14, CFR Part 135, as a scheduled domestic passenger flight operated by LAB Flying Service, Haines, Alaska, as Flight 609. The airline transport certificated pilot and the two passengers were not injured. Visual meteorological conditions prevailed, and VFR company flight following procedures were in effect. The accident flight originated at the Ketchikan Airport, Ketchikan, Alaska, about 1400.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on April 7, the pilot reported that during the landing roll on runway 02, he noted a significant airframe vibration, and a pronounced rumbling noise as the airplane slowed. He said that as he applied the brakes, the airplane veered to the left, and he was unable to keep the airplane on the runway surface. The airplane continued off the left side of the runway, and the nose of the airplane struck a drainage ditch. The airplane sustained substantial damage to the fuselage.

During a postaccident inspection, maintenance personnel discovered a broken landing gear oleo attachment bracket on the left main landing gear strut assembly.

The accident airplane's broken landing gear oleo attachment bracket, part number NB-40-0075, is the subject of a repetitive inspection procedure outlined in the Federal Aviation Administrations (FAA) airworthiness directive (AD) 2002-02-11, which allows two methods of compliance; the part may be replaced or the bracket must be inspected more frequently. The manufacturer has changed the design of the oleo attachment bracket which is made of aluminum alloy. The newly designed oleo attachment bracket, part number NB-40-0479 is made of steel. Installation of the newly designed, steel oleo attachment bracket significantly reduces the number of repetitive inspections required. Operators that elect to utilize the old style aluminum alloy oleo attachment brackets are required to conduct recurring inspections every 500 hours, or every 1,200 landings, which ever occurs first.

According to an FAA airworthiness inspector from the Juneau Flight Standards District Office (FSDO), who inspected the accident airplane's maintenance records, the aluminum alloy oleo attachment brackets were last inspected about 101.0 hours, and 218 landings before the accident. The FAA inspector noted that there was a substantial accumulation of dirt, grease, and oil on and around the broken oleo attachment bracket. The FAA inspector said that during the last main landing gear overhaul, the operator elected to install the old style aluminum alloy oleo attachment brackets, primarily due to the cost of the new style steel oleo attachment brackets.

NTSB Probable Cause

The fracture of the aluminum alloy landing gear bracket assembly, which resulted in a loss of control during the landing roll.