NTSB Factual Report

On October 19, 2013, at 1045 mountain daylight time, an experimental amateur-built Davenport model Long EZ airplane, N282RD, was substantially damaged during takeoff roll at Boulder Municipal Airport (BDU), Boulder, Colorado. The private pilot and his passenger were not injured. The airplane was registered to and operated by Ultrapure Air LLC, under the provisions of 14 Code of Federal Regulations Part 91, without a flight plan. Day visual meteorological conditions prevailed for the personal, local area flight that was originating at the time of the accident.

The pilot reported that the accident occurred as he was attempting a takeoff on runway 8 (4,100 feet by 75 feet, asphalt). He stated that during takeoff roll, shortly before liftoff, the airplane began to swerve to the left. He was unable to regain directional control before the airplane departed the left side of the runway. The airplane came to rest upright in a grass area located immediately north of the runway. The pilot reported that the left wing and the canard structural support were substantially damaged during the accident sequence. Additionally, he reported that the left main landing gear tire was found deflated following the accident. The pilot attributed his loss of directional control to a sudden deflation of the left main landing gear tire during the attempted takeoff. The pilot reported having 980 hours total flight time, of which 380 hours were completed in the accident airplane.

A postaccident examination was completed by inspectors with the Federal Aviation Administration (FAA) after the wreckage had been recovered from the accident site. Examination of the runway surface revealed a skid mark starting about 1,400 feet from the runway approach threshold. The skid mark exhibited a wavy double line pattern that was consistent with the width of a main landing gear tire. The wavy double marking continued another 400 feet until it departed the left runway edge. A white paint transfer mark was identified on the upper edge of a runway distance marker sign located about midfield. The FAA examination also confirmed that the left main tire was deflated and loose in its wheel assembly. The tire tread did not exhibit any localized scuff marks and the valve stem appeared undamaged. The examination did not reveal any additional anomalies with the airplane that would have prevented normal operation.

The nearest aviation weather reporting station was located at Vance Brand Airport (LMO), Longmont, Colorado, about 8 miles north-northeast of the accident site. At 1052, the LMO automated surface observing system reported: wind from 040 degrees at 3 knots, visibility 10 miles, sky clear, temperature 14 degrees Celsius, dew point 0 degrees Celsius, and an altimeter setting of 30.04 inches-of-mercury.

NTSB Probable Cause

The sudden loss of tire pressure during takeoff roll, which resulted in a loss of directional control.