History of Flight
On July 24, 2012, about 1900 eastern daylight time, a Hughes 269C helicopter, registration N9679F, sustained substantial damage following a loss of control and uncontrolled descent during a hover over the owner's business property in St. Petersburg, Florida. The pilot, who was the sole occupant, was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91.
According to the pilot, he decided to fly the helicopter to "lube parts." After liftoff, he brought it to a hover facing east at about 25 feet for approximately 5 minutes and initiated some pedal turns. The nose then began to drift to the right. He applied left pedal, but the helicopter was unresponsive and began to spin clockwise. It continued spinning for 6 to 8 complete 360-degree turns before he lowered the collective, and the helicopter impacted the ground on the left skid, struck a fence, and rolled over onto its left side.
Two witnesses reported observing the helicopter facing west, flying from side to side at 50 to 80 feet, appearing out of control in a U-shaped pattern, until it turned with its left side down and descended straight down. Both stated the helicopter did not spin in circles. Other witnesses provided similar accounts, though differing in some details; most observed the helicopter approximately 50 feet in the air, swaying or turning side to side, or turning clockwise and counterclockwise. None described spinning in circles. The helicopter was characterized as out of control before impact, and one witness estimated the entire flight from liftoff to impact lasted about 2 minutes.
Personnel Information
The pilot held a private pilot certificate with ratings for airplane single-engine land and rotorcraft-helicopter. His most recent FAA third-class medical certificate was issued on April 26, 2012. He reported 1,183 total flight hours, with 365 hours in the accident helicopter make and model. His last flight review was completed on January 20, 2010, approximately 30 months prior to the accident.
Aircraft Information
According to FAA records, the helicopter was manufactured in 1971. At the time of the accident, it had accrued approximately 2,393 total hours of operation. Maintenance records showed the last entry was in February 2000, when the last annual inspection was completed 12 years prior to the accident.
Meteorological Information
Weather recorded at Albert Whitted Airport (SPG) at 1900 included wind from 250 degrees at 6 knots, visibility 10 miles, clear skies, temperature 29°C, dew point 26°C, and an altimeter setting of 30.03 inches of mercury.
Wreckage and Impact Information
Examination by an FAA inspector revealed no evidence of preimpact mechanical failures or malfunctions that would have precluded normal operation. The tail rotor control rod had been severed just aft of the rod end bearing screw attaching to the forward tail rotor bellcrank. The forward end of the tailboom separated from the frame assembly, and the tail rotor control rod in the tailboom was bent at a 45-degree angle. One tail rotor blade and the tail stinger were severed. Control continuity was confirmed from the tail rotor pedals to the tail rotor bellcrank on the aft end of the frame.
The main transmission aft pinion nut was tight with cotter key intact and unbroken. The tail rotor driveshaft showed no abnormalities, though torsional twisting was present at its forward end exiting the tailboom.
During examination, the FAA inspector asked the pilot to actuate the cyclic control stick to check continuity. Initially, the pilot could not move the stick laterally, but then released the friction on the cyclic stick. Lateral movement was then possible, and continuity was confirmed up to the rotor head. Full longitudinal movement was not possible due to impact damage, but continuity was confirmed with slight movement observed. Collective control continuity was also confirmed.
Tests and Research
Review of the helicopter's cyclic control system revealed two cyclic friction controls: one for longitudinal and one for lateral friction. Each consisted of a linkage with a pilot-adjustable knob that compressed a stack of spring-loaded friction discs. The longitudinal friction linkage was located to the right of the cyclic stick; the lateral friction linkage was in front of and below the cyclic stick base. According to the type certificate holder, the friction controls, when tightened sufficiently, could serve as a control lock and prevent cyclic movement.
The Model 269C Pilot's Flight Manual, in the "Normal Procedures" section, states that before hovering and takeoff, the pilot should "release CONTROL frictions and set as desired."