Canopy Relative Work (CRW) may be described as the intentional maneuvering of two or more open parachute canopies in close proximity to, or contact with one another during descent. The most basic maneuver in CRW is the hooking up of two canopies, one below the other. This formation, known as a "stack" or "plane"(the difference between a stack and a plane is the grip on the parachute), is the most common maneuver in CRW.
There are two major categories of CRW formations:
- Vertical formations : Canopies are either stacked or planed one beneath the other. All grips should be on the center cell.
- Off-set formations : one or more docks and grips are on end-cells. These formations include diamonds, boxes and stair-steps.
USPA BSRs recommends a beginner should have the following qualifications before engaging in CRW:
- At least 20 jumps on a ram-air canopy.
- Thorough knowledge of canopy flight characteristics, to include riser maneuvers and an understanding of relative compatibility of various canopies.
- Demonstrate accuracy capability of consistently landing within five meters of a target.
Initial training would be conducted with two jumpers - the beginner and an Instructor experienced in CRW. The instructions should include lessons in basic docking and break-off procedures as well as emergency procedures.
USPA BSRs has the following recommendations on equipment:The following items are essential for safely doing CRW:
- hook knife -- necessary for resolving entanglements
- ankle protection -- adequate socks prevent abrasion from canopy lines. If boots are used, cover any exposed metal hooks
- short bridle cords -- short, single attachment point bridlecords are essential to reduce the danger of entanglement. Retracting bridle pilot chute systems are desirable
- cross connectors -- are essential for building planes. These should be connected between front and rear risers only.
The following items are strongly recommended for safely doing CRW:
- altimeter -- provides altitude information for dock, abort and entanglement decisions
- protective headgear -- must allow adequate hearing capability for voice commands, in addition to collision protection
- soft toggles -- provide less possibility of entanglement than hard toggles and better flight control
- trim tabs (go toggles) -- helpful for equalizing decent ratesand increasing control envelope
- cell crossporting (two rows) -- is recommended (when doneper manufacturer's specs) to minimize the likelihood of canopy collapse
- cascades -- recommended to be removed from the two centerA lines.