What it is
APRP-3.3.7.9, Horse Collar/Rescue Strop Type Helicopter Hoisting Gear, is a NATO Allied Personnel Recovery Publication. Its aim, in its own words, is "to standardize the horse collar/rescue strop type helicopter hoisting gear used by NATO forces and thereby help assure greater interoperability between national Search and Rescue (SAR) organizations." It is covered by STANAG 3295, the agreement through which the publication acquires force, and it names STANAG 7224, Water Survival Training for Aircrews and Designated Flying Personnel, as a related document without restating its content. Edition A, Version 1, promulgated in December 2021, is the edition in front of this page.
Who decides, and how it binds
The publication speaks to nations, not to a manufacturer or a certification body. It states plainly: "The make and model of strop to provide to their rotary wing assets is a national responsibility." Its own language toward a common standard is an invitation rather than a mandate: "Nations are encouraged to supply strops which meet or exceed the standard." A supplier meets APRP-3.3.7.9, where it meets it at all, because a national procurement specification or contract calls up its characteristics, not because the publication addresses a company directly.
The characteristics it sets
The publication sets five qualitative characteristics a horse collar or rescue strop has to meet, without expressing any of them as a number. It has to be strong and long enough to hold a survivor safely; be a bright colour to aid visibility during a rescue; carry a pictorial donning sequence on the strop itself, so an untrained person can still work out how to wear it; be designed, or have operating procedures, that stop a survivor slipping free during winching; and be buoyant for use over water. None of these is a dimension or a test threshold: the publication leaves the engineering that meets them to the nation and its supplier.
Where it sits, and what nations have varied
APRP-3.3.7.9 sits under STANAG 3295 in NATO's doctrine hierarchy. Adoption is not uniform: the publication's own Record of Reservations shows the Czech Republic recording that it will not provide SAR operations above sea level and that its gear is for trained personnel only, and France recording no commitment to the pictorial donning sequence. The publication is unclassified and, like every NATO standardization document, is issued by NATO free of charge; the Standardization Document Database is the authoritative source for the current list of reservations.
How you are evaluated
The publication names no certification body, no government quality-assurance surveillance, no notified body and no self-declaration route anywhere in its text. The nearest thing to a check it describes is the reservation process itself: a nation records, at the point of promulgation, where its own practice departs from the standard, rather than being assessed and passed or failed against it.