Helicopter rope suspension techniques (HRST) provide Marines with the ability to conduct helicopter insertions and extractions where helicopter landings are impractical. Marine Corps Reference Publication (MCRP) 3-1 l.4A, Helicopter Rope Suspension Techniques (HRST) Operations, establishes standards; serves as a guide for the realistic and safe training of Marines in HRST skills; and outlines the techniques, procedures, and equipment used to perform HRST. It is not intended to teach the basics of rope training or the basics of rappelling as they apply to cliff assault.