Possible Clues:

• Parachute opener
• One of the strings pulled to get on in the Parachute Regiment?
• Thing used to prevent you from dropping dead?
• Using pull, one may break a high-flyer's career
• It provides an opening for parachutists
• Device for releasing parachute
• It is pulled to open parachute
• It's pulled to secure the neck of a jumper
• Chutist's release
• Release for parachute