Accident Overview
On July 30, 2014, at approximately 1030 central daylight time, a Bell 206B helicopter, registration N866H, sustained substantial damage during engine start-up at David Wayne Hooks Airport in Spring, Texas. The helicopter was owned by Helicopter Services Inc. and operated by the Harris County Sheriff's Office as a local public aircraft flight. Visual meteorological conditions prevailed and no flight plan was filed. The pilot was not injured.
The pilot completed the preflight inspection while the helicopter was inside the hangar. After the helicopter was moved onto the ramp, the pilot was distracted by a phone call and did not perform an exterior check before starting the engine. The main rotor tie-down remained attached. During engine start, the pilot monitored cockpit gauges and noticed another officer approaching and waving. A "thump" was heard, prompting the pilot to initiate an emergency shutdown. The start was aborted at 15% N1, 25% N2, rotor rpm below 20% NR, and TOT within limits. No mechanical malfunction or system failure was reported.
Examination Findings
Post-accident examination revealed that the tie-down strap had broken during engine start and became entangled on the tail rotor output shaft. The strap struck the tail boom, causing dents and gouges over the last two feet, requiring skin replacement. The main rotor blade tip cap came loose; the blades were serviceable but replaced due to proximity to the replacement interval. Tail rotor blades were dented beyond limits and replaced. The vertical fin was gouged, and although repairable, it was replaced to avoid delay. The tail rotor gearbox, hub, and freewheeling unit required inspection for sudden stoppage, leading to overhaul. The aggregate damage was deemed substantial as it affected structural strength or performance and required major repair or replacement.