A Preferred Route Message (PRM) is a communication generated by operators that outlines their expected activities and route choices for flights over the North Atlantic (NAT) during a specific Organised Track System (OTS) period. This message is sent to the relevant Oceanic Control Area, such as Gander or Shanwick, and shared with all involved parties via the Aeronautical Fixed Telecommunication Network (AFTN).
As part of the Collaborative Decision Making (CDM) process for designing NAT tracks, operators planning to cross the NAT are encouraged to participate in the OTS planning. This engagement starts with the PRM system. To assist oceanic planners in considering preferred routes, all NAT operators—whether scheduled or non-scheduled—are urged to provide details about their optimal flight paths during peak traffic times. It’s best to send this information as early as possible, but no later than 1900 UTC for daytime OTS and 1000 UTC for nighttime OTS. The guidelines for submitting PRMs for daytime westbound flights can be found in the United Kingdom Aeronautical Information Publication (AIP), specifically in section ENR 2.2. For nighttime eastbound flights, similar information is available in the Transport Canada Aeronautical Information Manual (AIM) under NAT – North Atlantic (NAT) Operations.
The message format for PRMs varies depending on the direction of travel. For eastbound PRMs, the format includes priority, destination addresses, date and time of origin, origin address, message type, company name, and flight specifics. If there is no inland navigation fix, use the latitude crossing 080°W instead. Each city pair’s information must be repeated from departure to destination.
For example, an eastbound PRM might look like this: FF EGGXZOZX EGTTZDZE CZQXZQZX CZQMZQZX CZULZQZX CYHQZDZX KCFCZDZX KZNYZRZX BIRDZQZK LPPOZOZX 120936 EHAMKLMW PRM-KLM-E-160613-KJFK/EHAM TOPPS RIKAL 53/50 53/40 54/30 54/20 54/15 BABAN BLUFA 03 CYMX/EHAM YML HOIST 57/50 58/40 58/30 57/20 56/10 MAC BLUFA 01.
For westbound PRMs, the structure is similar but includes different elements, such as the first UK point and anchor point. Again, if there’s no inland navigation fix, use the latitude crossing 080°W. An example of a westbound PRM is: FF EGGXZOZX EGTTZDZE CZQXZQZX CZQMZQZX CZULZQZX CYHQZDZX KCFCZDZX KZNYZRZX BIRDZQZK LPPOZOZX 111824 LSZHSWRW PRM-SWR-W-160612-LSZH/KJFK BNE BEL 55/10 56/20 57/30 55/40 53/50 YAY TOPPS 02 LSZH/KIAD BNE BURAK 53/15 53/20 52/30 51/40 50/50 ELSIR TUSKY 01.
