NTSB Identification: ERA09FA417
14 CFR Part 91: General Aviation
Accident occurred Thursday, July 23, 2009 in Boonsboro, MD
Probable Cause Approval Date: 10/06/2010
Aircraft: ROBINSON HELICOPTER R44, registration: N7189W
Injuries: 4 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The helicopter arrived at Hagerstown Regional Airport, Hagerstown, Maryland, from Frederick Municipal Airport (FDK), Frederick, Maryland, about 1815, which was almost 2 hours later than scheduled, because of adverse weather. About 2000, the pilot and three passengers boarded the helicopter for the return flight to FDK; however, they subsequently returned to the airport terminal because of poor weather conditions.
According to witnesses at the airport, the pilot checked the weather while at the terminal several times. Further, he called a fellow employee of Advanced Helicopter Concepts (the operator of the helicopter), who lived about 4 miles from FDK, twice to ask about weather conditions at the airport. About 2100, the employee informed the pilot that the weather conditions were “miserable” with severe thunderstorms in the area. Sometime between 2200 and 2215, the employee told the pilot that the rain had stopped; however, he stated that it was still foggy and windy with lightning in the area. On both occasions, the employee offered to drive the helicopter occupants back to FDK; however, the pilot declined the offers.
A 2210 weather observation taken at FDK, located about 15 miles southeast of the accident site at an elevation of 303 feet above mean sea level (msl), indicated the following: visibility of 10 statute miles, thunderstorms and light intensity rain, and scattered clouds at 800 and 8,000 feet. A witness on the ground near the accident site reported that it was a “dark night” (civil twilight ended at 2101, and only 4 percent of the moon’s visible disk was illuminated) and that fog was present about 50 feet above the roadway surface. Given that the helicopter was only certified to be operated under visual flight rules, the pilot exercised poor judgment when he chose to fly back to FDK in dark night and adverse weather conditions.
The helicopter took off about 2215 and was flying over an interstate highway toward FDK when it entered an area of reduced visibility. The helicopter subsequently struck an unmarked, steel guy-wire that extended perpendicularly over the interstate, near the top of a mountain, and then crashed. During the final 2 minutes of the flight, the helicopter was flying at level flight about 1,100 feet above msl as the terrain elevation rose from about 600 to 1,200 feet above msl. A witness observed the helicopter fly into clouds and reverse direction just before impact. The accident sequence is consistent with controlled flight into an obstacle that the pilot most likely did not see because of the dark night conditions and reduced visibility.
The helicopter was equipped with a radar altimeter. Further, Robinson Helicopter Safety Notice SN-16 advises pilots to constantly be on alert for power lines because “flying into wires, cables, and other objects is by far the number one cause of fatal accidents in helicopters” and to “always maintain at least 500 feet AGL [above ground level], except during take-off and landing.” Safety Notice SN-26 states, “Many fatal accidents have occurred at night when the pilot attempted to fly in marginal weather...when it is dark, the pilot cannot see wires…Even when he does see it, he is unable to judge its altitude because there is no horizon for reference.”
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot’s improper decision to depart on a visual flight rules (VFR) flight at night in adverse weather conditions in close proximity to rising mountainous terrain in a helicopter that was only certified to be operated under VFR and his subsequent failure to maintain adequate clearance with wires. Full narrative available
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