Managing Flying Risk – Launch signalling
Launch signalling from the ground does not remove the responsibility for the safe conduct of the launch from the pilot in command.
Recognised methods of launch signalling
The recognised methods of launch signalling include radio and other wireless transmission, lights, and hand/bat signals. Release of the tow rope or cable by the glider or tug pilot on the ground signals the pilots intent not to launch.
To minimise the risk of a misunderstanding during launch signalling, which is a safety critical activity, ‘take-up slack’, ‘all out’ and ‘stop’ are the standard terms where verbal commands are used during launches.
Use of signalling lights and signalling by hand – limitations
Light or hand signalling can result in a delayed response, can be difficult to see (even when using bats for hand signalling) or interpret in poor visibility or against bright sunlight, and may not be seen once the launch progresses, for example when a tug pilot is focussed on starting the take-off.
Where signalling lights are utilised, they should not be red or green in colour.
Use of signalling lights and signalling by hand/bat – protocol
- Take up slack: light dashes of one second duration and three seconds interval.
- All out: light dots at one second interval.
- Stop: steady light.
Signalling by hand:
- Take up slack: arm swung underarm.
- All out: arm swung from side to side above the head.
- Stop: arm held stationary vertically above the head.
Signalling – aerotow.
Radio communication should be established between the launching operation and the towing aircraft. Where radio communication is not possible, another of the recognised methods of signalling to stop the launch should be available.
Signalling – wire launches
The method of communication used between the launch point and winch (or tow car) should result in reliable signalling for the duration of each launch and may be visual or audible. It is highly desirable for the signalling system to reliably allow an immediate audible and visual STOP command to be sent to the winch driver. Wireless signalling can provide near-instant communication to audible and visual indicators in the winch cab. Please note that a short period at the start of a personal management radios (PMR) radio transmission can be lost during channel identification. This shortcoming can be addressed by repeating the launch command, eg. “All out. All out” or “Stop. Stop”.