Beech 58 N3700N accident near Portland, Oregon

Probable cause

The overstress failure of a nose landing gear mechanism bolt, which precluded the nose gear retract brace assembly from locking the nose gear in the extended position and allowed the nose landing gear to collapse. Contributing to the accident was the failure of the nose gear tire's inner tube.

NTSB analysis

During takeoff roll, with the airplane between 60 to 70 knots, the inner tube in the nose gear tire failed, causing the tire to flatten and skid and the nose gear to subsequently collapse. The pilot successfully aborted the takeoff and steered the airplane to a stop onto grass just off the right side of the runway. A postaccident examination of the airplane's nose landing gear retract mechanism revealed that the bolt which connects the mechanism's inboard and outboard arms in place had failed in overstress, likely due to the skidding nose gear tire. The failure of the bolt allowed both arms to pivot enough to keep the nose gear retract brace assembly from locking the nose gear in the extended position, which allowed the nose landing gear to collapse.

Text from the NTSB. Open the NTSB docket for WPR10LA147 for the full record.