Pocket ripcord handle. Elastic or spring-edged pocket that holds ripcord handle in an accessible position on the harness. The chest-type pocket consists of a piece of straight elastic webbing serving the same purpose. 

Porosity. The ratio of void or interstitial area to total area of a cloth expressed in percent. The ratio of open space to covered area of a drag surface. Used for ring slot, ribbon, ring sail, and rotafoil canopies. Not to be confused with permeability. 

Premature opening.  Any accidental opening of the parachute prior to the intended time. 

Prepack inspection.  The inspection made on the parachute prior to its packing. 

Presser foot. The part of the sewing machine above the feed dog that holds the fabric in place. 

Preventative maintenance (PM).  The systematic care, servicing, and inspection of equipment and facilities for the purpose of maintaining them in a serviceable condition and detecting and correcting incipient failures. Simple or minor preservation operations and the replacement of small standard parts not involving complex assembly operations. 

Proof load. The testing of an item for conformance with strength requirements. 

Proper layout.  Process by which the canopy and suspension lines are arranged on the packing table for inspection and packing. 

Pull the dot.  A particular type of snap fastener that can only be opened or closed by pulling in one direction designated by an indented dot on the button. 

Pull-up cords.  Nylon cords of varying length used to pull up the sides and ends of the container flaps over the container cones and to pull the cones through the grommets.They are also used to pull the suspension lines into place in some types of containers. 

## Q 

Quality control. A method of describing the inspection and test procedures necessary to ensure that each article produced conforms to the type design and is in a condition for safe operation. 

Quick connector snap.  A large hook-shaped, spring-loaded snap, two of which are used to quickly attach the chest-type parachute to the two D-rings on the harness. 

## R 

Radial seam. A seam extending from the skirt to the apex, joining two gores. A portion of the suspension lines may be concealed in the tube formed by the radial seam. 

Ram-air parachute. Generally, a rectangular, double- surface canopy with airfoil shaped ribs inflated by the air flowing into the front openings to produce an airfoil shape. 

Rate of descent. The vertical velocity, in feet per second, of a fully-opened parachute. 

Rating. A statement that, as a part of a certificate, sets forth special conditions, privileges, or limitations. 

Ravel (unravel). To separate, untwist, or unwind, leaving a frayed or ragged edge. “Unravel” is often used with the same meaning, although grammatically incorrect. 

Raw edge. The unfinished edge of the material; liable to raveling. 

Reefing. A temporary restriction of the skirt of a parachute to a diameter less than the fully inflated diameter. Reefing is used to decrease drag area and/or to obtain stability. 

Reinforcements. Commonly strong tape or webbing used to strengthen parts of the canopy, container, or harness. 

Relative humidity. Ratio of the amount of water vapor present in the air to that which the air would hold at saturation at the same temperature. 

Repack cycle. The time that a certificated parachute is considered to be airworthy before being inspected and repacked. The current U.S. repack cycle is 180 days. 

Reserve parachute. The second or “auxiliary” parachute worn by a person making a premeditated jump. 

Reserve static line (RSL). A backup device for activating the reserve after a cutaway. Usually a line, webbing, or cable that connects the main risers with the ripcord handle, housing, or cable. 

Restitching. The process of sewing directly over base or broken stitching. 

Retainer band. A rubber band used to hold folded suspension lines or static lines to the parachute pack. 

