History of Flight
On August 27, 2012, at 08:03 Pacific daylight time, an Arrow Falcon Exporters Inc OH-58C helicopter, registration N503DR, crashed in an almond orchard near Escalon, California. The helicopter was operated by Del Rio Aviation, Inc. under 14 CFR Part 137 for agricultural application. The commercial pilot sustained serious injuries, and the helicopter was substantially damaged. Visual meteorological conditions prevailed, and no flight plan was filed.
The pilot had flown a 30-minute flight from his base to the orchard, where the helicopter's hoppers were loaded with 80 gallons of application product from a mixing truck. According to the truck driver, the helicopter appeared to be nearly finished with the load when it was observed about a mile away. The helicopter banked up to the right at an angle that seemed steeper than normal, then disappeared and did not reappear. The driver went to the location and found the helicopter crashed. No post-accident fire occurred.
The pilot stated in the NTSB Form 6120 that he had no memory of the accident.
Personnel Information
The pilot, aged 71, held commercial pilot certificates for airplane single-engine and multiengine land, airplane single-engine sea, instrument airplane, and rotorcraft-helicopter, issued January 15, 2007. He held a second-class medical certificate dated January 12, 2012, with the limitation that he must have glasses available for near vision. The pilot reported 15,653 total flight hours, including 11,075 hours in helicopters performing agricultural application.
Aircraft Information
The helicopter, serial number 71-20679, was manufactured in 1971. It was powered by a Rolls Royce T63-A-720 turboshaft engine rated at 420 horsepower. The most recent annual inspection was completed on July 18, 2012, at a total airframe time of 6,429.2 hours. Engine total time was 4,318.3 hours. The most recent 100-hour inspection was completed on August 26, 2012, at a total aircraft time of 7,019.3 hours.
The helicopter was equipped with an Arrow Falcon Exporters Inc Model 3900-OH58 Spray System under Supplemental Type Certificate SR00268LA. This system consisted of two 70-gallon cylindrical chemical tanks attached by quick disconnect pins to an H-frame support bolted to the landing gear attach fittings. The tanks were connected via a cross-feed tube, allowing filling from either side. The center spray boom was 70 inches long, mounted at airframe station 22, with provisions for 12 spray nozzles or down tubes. Outboard spray booms connected to the center boom and to the H-frame via vertical and horizontal struts.
Wreckage and Impact Information
The main wreckage came to rest between rows of almond trees on its right side. Several almond trees were damaged in the area. The main rotor hub remained attached to the mast, and both rotor blades had sheared off approximately 3 feet from the hub center. The tail boom was attached, and the tail rotor was connected. The right-side hopper tank was crushed, and the right landing skid had separated from the cross tubes at the attachment points. The hopper cross-feed tube was connected to both tanks. The right spray bar was bent and collapsed under the helicopter, while the left spray bar remained in place. The sheriff reported detecting the odor of agricultural chemical and jet fuel at the scene.
A Federal Aviation Administration inspector examined the helicopter on-site. The tail rotor and engine-to-transmission drive shafts had separated in shear. The tail rotor gearbox rotated freely, and no metal chips were found on the gearbox chip detector. The engine oil level was full, and the lower chip detector was free of metal chips. Control system continuity was established. No mechanical malfunctions or failures were found that would have precluded normal operation.