History of Flight
On February 3, 2014, about 1350 eastern standard time, a Hughes 369D, N8618F, operated by the Collier Mosquito Control District, was substantially damaged during a practice 180-degree autorotation to touchdown at Naples Municipal Airport, Florida. The flight instructor and airline transport pilot were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local public use training flight.
According to the flight instructor, prior to the last practice autorotation, they had performed two running landings, two stuck left pedal maneuvers, three stuck right pedal maneuvers, and eight successful autorotations. On the final autorotation, the helicopter lost altitude suddenly and contacted the ground. The instructor took control and landed the helicopter, which had yawed 90 degrees to the right.
The airline transport pilot reported that he was undergoing annual proficiency training. Four straight-in touchdown autorotations were performed, followed by three 180-degree autorotations. The first two were successful, but during the third, the tail of the helicopter contacted the ground. The flare was initiated about 50 feet above ground level, and he felt a bump. The helicopter landed with little forward motion and came to rest turned right.
A witness observed the helicopter falling more rapidly and aggressively than previous approaches. At about 100 feet agl, the helicopter nose up aggressively, the tail struck the ground, dirt was thrown, and the helicopter came to rest with the main rotor still turning.
Personnel Information
The flight instructor held a commercial pilot certificate with rotorcraft-helicopter and instrument-helicopter ratings, a flight instructor certificate with rotorcraft-helicopter and instrument-helicopter ratings, and an instrument ground instructor certificate. His most recent FAA second-class medical certificate was issued July 1, 2013. He reported 5,465 total rotorcraft hours, with 1,549 hours in the accident make and model, and 3,884 hours as a flight instructor.
The pilot held an airline transport pilot certificate with airplane multi-engine land and commercial privileges for airplane single-engine land and rotorcraft-helicopter. He also held a flight instructor certificate for airplane single-engine. His most recent FAA first-class medical certificate was issued January 29, 2014. He reported 4,935.3 total flight hours, with 1,061.5 hours in the accident make and model.
Aircraft Information
The accident aircraft was a light, single-engine utility helicopter manufactured by Hughes Aircraft Corporation in 1977. It was powered by a 420 shaft horsepower Allison 250-C20B gas turbine engine. The main rotor was a fully articulated five-bladed system, and anti-torque was provided by a two-bladed semi-rigid tail rotor. The airframe incorporated a rigid truss structure with roll bar design. The fuselage included a pilot compartment with two seats, a passenger/cargo compartment, an aft section for tailboom attachment and engine, and a lower section housing fuel cells. The landing gear was skid-type with nitrogen charged dampers. The helicopter's most recent annual inspection was completed December 4, 2013, at about 3,344.6 total hours.
Meteorological Information
At 1253, about 57 minutes before the accident, weather at APF included winds from 220 degrees at 12 knots, 10 miles visibility, scattered clouds at 2,400 feet, and broken clouds at 5,500 feet. At 1353, about 3 minutes after the accident, winds were 220 degrees at 12 knots, visibility 10 miles, and scattered clouds at 2,500 feet.
Airport Information
Naples Municipal Airport was a tower-controlled public use airport located 2 miles northeast of Naples, Florida, with an elevation of 8 feet. It had two paved runways (05/23 and 14/32) and a turf runway. Two areas could be used for autorotations—a hard surfaced taxiway and the turf runway. At the time, the turf runway was in use due to traffic.
Wreckage and Impact Information
Examination revealed that the tail rotor blades exhibited impact damage and were twisted and bent. The tail rotor driveshaft was twisted and bent, the horizontal stabilizer was bent, and forward and aft tail rotor driveshaft couplings were damaged. The tail rotor driveshaft dampener was distorted, and the tail rotor output shaft on the transmission was bent.
Previous Training Accident
NTSB records indicated that N8618F had been involved in a previous accident on March 11, 2010 (ERA10LA172), with similar circumstances. The helicopter was substantially damaged after a landing during a yearly check ride. Neither the commercial pilot nor the check pilot was injured.
Additional Information
In response to the accident, MD Helicopters modified their standard operating procedures on February 10, 2014, to require that autorotation training be conducted to smooth, hard surfaces. On March 28, 2014, the Collier Mosquito Control District stated they would conduct future training at MD Helicopters' facility in Mesa, Arizona.