Flight Details
The helicopter departed Pendleton on an emergency medical services (EMS) flight to transport a patient to Portland. After delivering the patient, the pilot took off on the return flight with two medical personnel aboard. During arrival at 1658 PST, the pilot requested a Special VFR (SVFR) clearance to the Pendleton airport. The pilot was advised to hold and expect clearance at about 1725. After inbound traffic had landed, an SVFR clearance was issued.
Mayday Call
About five minutes later, the pilot transmitted a mayday call stating that he had 'inadvertent IFR' and was not capable of IFR flight. At 1732, the last transmission from the pilot indicated he was at 2,200 feet MSL 'approximately 5.1 NM from . . .'
Accident
Subsequently, the helicopter impacted the ground about 5 miles west of the airport, while descending in a right bank. No preimpact part failure or malfunction was found.
Aircraft Information
Reportedly, the helicopter had departed Portland with the oil temperature gauge inoperative, the transponder removed, and a leak in the pitot static system.
Weather
At Pendleton, the 1650 PST weather was, in part: 700 feet overcast, visibility 3 miles with fog.
Pilot Certification
The pilot was not certificated for instrument flight in helicopters.