On July 23, 1998, a Champion 7GCBC (registration N21262) was involved in an aviation accident near Clearwater, MN. Investigators recorded the probable cause as: The inadequate visual lookout by the pilot-in-command. The unmarked transmission wire was a contributing factor. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot reported striking unmarked power lines while in level flight at 75 feet altitude; the poles were obscured by trees and the lines were not depicted on the sectional chart, which includes a caution that not all obstacles are shown.
Incident Details
The pilot reported that while in level flight heading southbound at an altitude of 75 feet, the airplane impacted power lines. The power lines were not marked and were not depicted on the current sectional chart, which the pilot had consulted prior to flight.
Pilot Report
The pilot added that the poles supporting the power lines were obscured by trees along the shoreline, making them difficult to see in flight. The pilot had consulted the sectional chart before the flight but found no indication of the power lines.
Chart Information
Examination of the Twin Cities Sectional Aeronautical Chart reveals the following caution: "CAUTION: This chart is primarily designed for VFR navigational purposes and does not purport to indicate the presence of all telephone, telegraph and power transmission lines, terrain or obstacles which may be encountered below reasonable and safe altitudes."