Event Overview
A helicopter operating from a building rooftop experienced a loss of engine RPM shortly after takeoff and subsequently crashed. The aircraft was turned into the wind prior to departure. According to the pilot, as forward movement began, the RPMs started to drop, with manifold pressure indicating 24 inches. The pilot continued forward, manipulating the collective and throttle to clear a two-story building adjacent to the takeoff point.
Pilot Report
The pilot stated: "When I cleared the roof line, I dropped the collective, rolled the throttle and aft cyclic, but [I] didn't have enough altitude to recover, and into the ground we went." No further details on the pilot's actions or the aircraft's performance were provided in the report.
Aircraft Examination
A post-accident examination of the helicopter revealed no mechanical anomalies. The helicopter was found to be in normal operating condition, with no pre-existing defects identified.
Weather Conditions
Weather data from Anoka, Minnesota, located 10 miles south-southeast of the accident site, was recorded 20 minutes before the accident. Conditions included an 800-foot overcast ceiling, 2 miles visibility in fog, temperature 60°F, and dew point 58°F.
Carburetor Icing Information
Reference to DOT/FAA Publication CT-82/44, "Light Aircraft Piston Engine Carburetor Ice Detector/Warning Device Sensitivity/Effectiveness," dated June 1982, indicated that for a temperature of 60°F and dew point of 58°F, the carburetor icing probability chart shows "serious icing conditions at cruise power." The report did not state whether carburetor icing contributed to the accident.