Accident Overview
On June 7, 2018, at 1340 central daylight time, a Robinson R44 II helicopter, registered N755KT, was substantially damaged during a forced landing to salt water following a loss of engine power near Fort Morgan, Alabama. The commercial pilot, who was the sole occupant, was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the ferry flight conducted under 14 Code of Federal Regulations Part 91.
Pre-Accident History
The helicopter departed Gac Waterfront Heliport (FD32) in Navarre, Florida, and was destined for Baton Rouge Metropolitan Airport (BTR) in Baton Rouge, Louisiana. The pilot was delivering the helicopter to a Robinson factory service center at BTR. According to the pilot, the helicopter had been experiencing trouble with idle power, stumbling at idle but performing normally at high-power settings. A local mechanic was unable to diagnose the issue, prompting the decision to have Robinson inspect the helicopter. At engine start, the engine idled smoothly and accelerated without issue, running continuously until the power loss in cruise flight.
Accident Sequence
While cruising at 400 feet above ground level along the beach at 110 knots, the pilot felt a violent shaking, initially attributing it to turbulence. He added aft cyclic, lowered the collective, and scanned the instruments. The shaking stopped, revealing zero oil pressure, an illuminated oil pressure warning light, and decaying rotor rpm. The pilot promptly entered autorotation. The beach was crowded, so he selected an unoccupied area in the water just off the beach for the forced landing.
Pilot Information
The pilot held a commercial pilot certificate and a flight instructor certificate, each with ratings for rotorcraft-helicopter and instrument helicopter. His Federal Aviation Administration (FAA) second-class medical certificate was issued on March 27, 2018. He reported 811 total hours of flight experience, of which 747 hours were in the Robinson R44.
Aircraft and Engine Information
According to FAA records, the helicopter was manufactured in 2004. Its most recent annual inspection was completed on April 25, 2018, at 1,395.1 total airframe hours. During that inspection, the Lycoming IO-540-AE1A5 engine was reinstalled after an overhauled crankshaft and counterweights were installed, along with other work. The helicopter had accrued 29 hours since the inspection.
Weather Conditions
At 1335, the weather recorded at Sonny Callahan Airport (CQF), 16 miles north of the accident site, included scattered clouds at 6,000 feet, winds from 270 degrees at 3 knots, temperature 30°C, dew point 19°C, and an altimeter setting of 30.00 inches of mercury.
Post-Accident Examination
The wreckage was examined at the site by an FAA aviation safety inspector. The tail rotor and its associated gearbox had separated from the helicopter and were recovered from the water. An NTSB air safety investigator examined the engine about one week after its recovery. The magnetos had been removed from the engine, opened, and were found lying by the pilot's seat. Several wire bundles were cut, and electrical system continuity could not be verified. The spark plugs were removed, and the interior of the engine was examined with a lighted borescope. All pistons and valves appeared intact, in good condition, and displayed evidence of salt water corrosion. The engine's crankshaft was rotated by hand using the fan, and thumb compression was obtained on all cylinders. Continuity was confirmed through the powertrain and valvetrain to the accessory section. The mechanical fuel pump pumped fluid when actuated by hand. The auxiliary pump did not operate when electrical power was applied; its electric motor was disassembled and found to have burnt brushes, wiring, and some windings. The pump was dry and showed no evidence of water contamination. According to the helicopter manufacturer, engine operation can be sustained by the engine-driven pump alone.