Safety Analysis of the Winch Launch

Abstract

In 2004 the British Gliding Association (BGA) formed a Safety Initiative Team to determine actions to improve the gliding accident rate in the UK.  Analysis of the accident record from 1987 to 2004 showed that there was scope for action to reduce the hazards associated with incomplete winch launches.  It was evident from the accident data that many of the most serious winch launch accidents—those resulting in either fatal or serious injury—can be divided into two classes: stall during rotation into the climb; and power loss at low level.  This paper describes two simple modelling tools which were created to assist Browning and others to assess the important factors which can lead to dangerous conditions in each of these cases.  To permit the user easily to assess ‘what-if’ cases the tools were constructed using a readily available spreadsheet program (Microsoft Excel), which also allowed immediate graphing of the results.  In addition the Appendix gives consideration to what is meant by the pilot’s perception of normal acceleration judged by the force exerted by the glider seat.