ASSESSMENT OF HELICOPTER WIRE STRIKE ACCIDENTS AND SAFETY WARNING AND PROTECTION DEVICES

摘要

Wire strike accidents involving U. S. military and civil helicopters for the period 1994 - 2004 were analyzed using military and NTSB safety databases. During this period U.S. Army helicopters have been involved in total of 1,160 accidents, out of which 34 have been related to wire strikes. There have been 147 fatalities in helicopter accidents, out of which 7 have been in wire strike accidents. The cost of accidents (Class A -C) during this period has been USD1,483 millions and the cost of wire strike related accidents has been USD87.5 million. There has been a noticeable decrease in the number of wire strike accidents after about 1990 when military started equipping helicopters with Wire Strike Protection Systems. The total number of accidents in civil helicopters has shown an increasing trend from 1996. For example, there were 212 accidents involving 67 fatalities in the year 2003 alone. Between the years 1994 and 2004, there were 124 wire strike accidents out of which 41 were fatal accidents resulting in 65 fatalities, 45 serious injuries and 42 minor injuries. Compared with the number of wire strike accidents during the period from 1970 to 1979, there was a 40% decrease in the number of wire strike accidents during the period from 1994 to 2003. During the period from 1994 to 2004, general aviation operations accounted for approximately 60% of all the wire strike accidents while agricultural operations accounted for approximately 27% of the accidents. The majority of accidents involved pilots whose ages were between 40 and 59 years and who had more than 2000 hours of flight experience. In addition to wire strike protection devices, there are a number of devices that warn the pilot about the proximity of wires. Some of these devices are reviewed and their potential for preventing wire strikes is assessed.