On March 27, 1989, a Mbb BK-117-A-3 (registration N39187) was involved in an aviation accident near Coinjock, NC. Investigators recorded the probable cause as: FAILURE OF THE CELLULAR COMPANY TO PROPERLY INSTALL AN OPERATIONAL LIGHTING SYSTEM ON A NEWLY CONSTRUCTED TRANSMISSION TOWER. DARKNESS AND THE COMPANY'S FAILURE TO NOTIFY FLIGHT SERVICE OF THE UNLIGHTED TOWER WERE RELATED FACTORS. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter returning to its home base collided with a newly constructed 240-foot cellular antenna tower. The tower's beacon was not operational, and the supervisor did not notify Flight Service of the tower's height or inactive beacon.
Accident Overview
A helicopter operating along a customary route to its home base collided with a cellular phone antenna tower. The structure had been completed on the same day as the incident. Examination of the wreckage revealed that the helicopter's rotor system struck the tower approximately 15 feet below its top.
Tower Construction and Beacon Status
The antenna tower, which stood 240 feet tall, had its final 100-foot section erected near sunset. According to the field supervisor, there was insufficient time to complete the electrical connection for the installed beacon. As a result, the tower was not illuminated. The supervisor also failed to inform Flight Service of the tower's height and the fact that the beacon was not operating.
Flight Operations
A pilot familiar with operations at the county's flight base noted that the majority of flights in the area were conducted at altitudes between 100 and 500 feet above ground level (AGL).