History of Flight
On November 11, 2008, at about 0610 eastern standard time, a Bell 206B helicopter, registration N281CB, operated by Aircoastal Helicopters, Inc., was substantially damaged when it impacted the ground during a forced landing. The flight had departed Palm Beach County Park Airport (LNA) in Lantana, Florida, at about 0602. The helicopter was conducting a local traffic report flight for a television station under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed.
After departure, the helicopter climbed to approximately 1,000 feet above ground level and flew south before turning northbound. Shortly after the turn, the helicopter yawed to the left, and low rotor and engine out warning systems activated. The pilot entered an autorotation and achieved normal rotor rpm. He selected a landing site on a road within an industrial park. As the helicopter approached, the pilot noticed powerlines spanning the road. He used the collective control to clear the powerlines, and the helicopter impacted in a grass area along the road.
Personnel and Aircraft Information
The pilot, age 51, held an airline transport pilot certificate and a flight instructor certificate, both with helicopter ratings. His most recent FAA second-class medical certificate was issued on November 13, 2007. He reported 2,708 total flight hours, including 137 hours in the accident helicopter make and model. His last biennial flight review was completed on January 24, 2008.
The helicopter was manufactured in 1981 and issued an airworthiness certificate on April 16, 1981. It was equipped with an Allison 250-C20B gas-turbine engine. Airframe logbook entries dated October 9, 2008, indicated compliance with the manufacturer's 100/200 hour inspections. Engine logbook entries dated November 8, 2008, showed the engine gearbox had been opened and inspected with no defects found. The airframe had 12,540.70 total hours and 12,391 cycles; the engine had 14,420.70 total hours.
Meteorological Conditions
At 0619, the recorded weather at Palm Beach International Airport, 10 miles north of the accident site, included wind from 060 degrees at 10 knots, few clouds at 2,600 feet above ground level, broken clouds at 4,100 feet, overcast at 4,700 feet, 10 miles visibility, temperature 24 degrees Celsius, dew point 18 degrees Celsius, and an altimeter setting of 30.02 inches of mercury.
Wreckage and Examination
Examination of the wreckage revealed the tail boom was severed aft of the horizontal stabilizer, the landing skids and rear cross tube were damaged, the hull was damaged, and the fuel cell was ruptured. Engine and tail rotor continuity were verified from the driveshaft and from the tail rotor forward to the separation. Flight control continuity was confirmed. A loose pressure compressor (Pc) line from the power turbine governor to the fuel control unit was found, with the "B"-nut loose to the point of no thread engagement.
The wreckage was recovered to the owner's hangar under FAA supervision. The engine was sent to Rolls-Royce in Indianapolis, Indiana, for further evaluation. On January 13, 2009, the engine was examined. The "B"-nut was placed as found with no thread engagement. The engine was started, warmed up, and throttle advanced to 65 percent N1, where it experienced an uncommanded power reduction and decelerated to a sub-idle setting. A visual examination showed the "B"-nut had loosened, creating a gap between the Pc line and the T-fitting. After the line was reinstalled and the "B"-nut tightened to proper torque, the engine restarted and ran within production test standards.