Accident Details
On June 30, 2018, at about 1255 Atlantic standard time, a Bell 206B helicopter, registration N10CV, was substantially damaged in an accident in Rio Grande, Puerto Rico. The private pilot was fatally injured, and three passengers sustained minor injuries. The flight was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The helicopter departed from Fernando Luis Ribas Dominicci Airport (TJIG), San Juan, Puerto Rico, about 1236, and was destined for Villa Marina Heliport (PR26), Fajardo, Puerto Rico. According to a passenger in the right rear seat, the first minutes of the flight were normal, then he felt "a pull from the ground" and the helicopter began to descend. The left front seat passenger reported observing a zero reading on the torque meter and more than two illuminated lights on the instrument panel a few seconds before ground impact. The pilot stated, "we lost the engine, we need to land" and searched for a landing spot. The right rear passenger heard a "beep beep" sound consistent with an engine out warning. The pilot attempted to land on a road, but the passenger felt the helicopter "just fall down and crash."
Aircraft and Engine Examination
A Federal Aviation Administration inspector examined the helicopter at the accident site, about 19 miles from TJIG and about 9 miles northwest of PR26. The helicopter came to rest upright and canted to the right. Substantial damage was noted to the fuselage and main rotor system. All major components were accounted for. Slight oil streaking was observed on the left and right sides of the aft fuselage. The oil tank was undamaged but contained no oil. The oil filler cap was secure, and the oil level did not register on the dipstick. About 9.5 ounces of oil were drained from the oil supply system, including the tank, lines, cooler, and filter. The oil filter was not in bypass and contained a small amount of contaminants. No oil leaks were found at the oil cooler or flexible hoses; all hoses were intact and pressure tests showed good condition.
The engine remained securely attached to the airframe with no visible external impact damage. Application of aircraft battery power confirmed an illuminated engine chip light on the master caution panel. Engine oil drained from the accessory gearbox measured less than 6 ounces and contained slight metallic debris, but no significant anomalies were noted in testing.
All main bearings were examined. The No. 1 bearing was coated in oil and rotationally free. The No. 2 bearing exhibited heavy cage damage with deformed balls. The No. 2.5 bearing was dry. The No. 3 bearing had oil and light drag. The No. 4 bearing was oiled and free. The No. 5 bearing showed heavy drag and spalling to all balls. The No. 6 bearing was dry with light scoring. The No. 7 bearing was seized by metal material. The No. 8 bearing was dry with light drag. The damage to most bearings was consistent with thermal distress, with amber discoloration. No blockages were found in the oil delivery tubes. Disassembly of the compressor revealed heavy circumferential rub damage to the compressor shroud and corresponding damage to the impeller.
Flight control continuity was confirmed for collective, anti-torque, and cyclic. No preimpact anomalies were noted with the fuel and hydraulic systems or the main and tail rotor drive systems.
Medical and Pathological Information
An autopsy of the pilot was performed in San Juan, Puerto Rico. The cause of death was blunt force injuries. Toxicology testing returned negative results for carbon monoxide, ethanol, and drugs of abuse. Prescribed medications for the pilot's known conditions were present, none considered impairing. Additionally, 0.092 ug/ml of diphenhydramine (a sedating antihistamine) was identified in the pilot's blood. The report notes that diphenhydramine can impair cognitive and psychomotor performance and cause drowsiness, and that it typically carries a warning regarding performance of tasks like driving or operating heavy machinery. It also notes that diphenhydramine undergoes significant postmortem redistribution, with central blood levels possibly increasing about three times.