InFO 12016: Reduced Longitudinal Separation Minimum (RLongSM) Trial

InFOInformation for Operators

U.S. Department InFO 12016

of Transportation DATE: 9/17/12

Federal Aviation

Administration Flight Standards Service

Washington, DC http://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/info An InFO contains valuable information for operators that should help them meet certain administrative, regulatory, or operational requirements with relatively low urgency or impact on safety.

Subject: Reduced Longitudinal Separation Minimum (RLongSM) Trial

Purpose: This InFO advises pilots flying within the Gander and Shanwick Oceanic Control Areas (OCA) in the North Atlantic (NAT) airspace that an RLongSM trial is ongoing.

Background: Gander and Shanwick OCA centers have implemented a trial of five-minute longitudinal separation minimum to be applied between eligible aircraft. This trial supports the development of a separation minimum to aid in obtaining optimum vertical profiles.

Discussion: To be eligible to participate, aircraft must have a flight plan, use Automatic Dependent Surveillance-Contract (ADS-C) and Direct Controller Pilot Communications (DCPC) provided via controller–pilot data link communications (CPDLC). In addition, the flights must have reported passing a common point from which they follow the same or continuously diverging routes. The current turbo jet, constant Mach, same track longitudinal separation minimum in the NAT minimum navigation performance specifications (MNPS) airspace is 10 minutes.

The five-minute longitudinal separation minimum used in the trial becomes available once eligible aircraft have entered the Gander or Shanwick OCA and the aircraft is equipped with FANS1/A (ADS-C and CPDLC) and a data link connection is established with air traffic control (ATC).

Operators do not need to apply to be part of the trial. Pilots simply have to request a change in altitude, be properly equipped, and have MNPS approval. Eligible aircraft benefit by having a greater opportunity to climb to more fuel-efficient levels, climb through or follow another eligible aircraft at the same level and, change mach or altitude due to turbulence or bad weather.

Application of this specific procedure by ATC will be transparent to flights that have received an altitude change clearance. As always, flightcrews must adhere to the ATC cleared Mach number and report any failure or malfunction of their global positioning system (GPS), ADS-C, or CPDLC equipment to ATC as soon as it becomes apparent as the separation standard is dependent on aircraft equipment performance. Strategic Lateral Offset Procedure (SLOP) is unaffected.

Recommended Action: Directors of safety, directors of operations, chief pilots, dispatch supervisors, fractional ownership program managers, training managers, and operators of aircraft should make their flight crews aware of the content of this InFO.

Contact: Questions or comments regarding this InFO should be directed to Dennis Mills, New Program Implementation and International Support Branch, AFS-240 at (202) 493-4901.

Distributed by: AFS-200 OPR: AFS-240