CABLE HANG-UPS
There have been four recent incidents with pilots being unable to release the launch cable. In each case effective action has averted an accident. In three of the incidents the launch cable became entangled with the nose wheel. In the other incident the release mechanism was jammed by a washer.
There are some lessons to be learned (or perhaps relearned) from these incidents:
• Rope or a flexible or worn strop is likely to get entangled when the glider overruns it • Always pull the release and stop the launch if the glider overruns the cable – it may become entangled • To be effective a stop signal must be given swiftly and must be seen or heard by the tug pilot or winch driver • A visual stop signal given after the tug has opened full throttle is unlikely to be seen (even with a forward signaller) • Radio communication between the launch controller, glider and tug is generally the best option • Cable guillotines (on winch or tug with retractable rope) don’t always work – how often do you check yours? Giving the UNABLE TO RELEASE signal to the tug isn’t as straightforward as you might think. The guidance in the BGA Instructors’ Manual is as follows:
If in a two-seater, try the other release first. If you are in radio contact, talk to the tug. Otherwise, fly well out to the left of the tug (to a position where the tug pilot can see you) and rock your wings positively from side to side. Rock first left and furthest, or you’ll end up swinging back towards the middle. While out to the left you may need a small amount of airbrake to keep the rope tight. The tug pilot will tow the glider back to the airfield and then release his end of the rope.
Andy Holmes (the BGA winching adviser) recommends the following parachute/strop layout for winching:
Tost rings to weak link 3m (+/- 0.5m) of stiff rope or cable in stiff hose/pipe. The 3m strop is recommended to get the weak link out of the front of a nose wheel or skid but not long enough to flick back and hit the tailplane if a weak link breaks. The slotted end of any weak link holder should face towards the glider so that the weak link holder isn't fired back at the glider if the weak link breaks.
Weak link to parachute 17m (minimum 12m) of similar material but this doesn't need to be covered in hose or pipe.
This gives 20m (min 15m) total distance from Tost rings to parachute to minimise problems of the glider flying into the parachute during real or simulated launch failures.