North Atlantic (NAT) and West NY (WATRS) Operational Changes 2019
Updated: 8/21/2019
NEW: Micro-Slop Procedure in the NAT (see item 3)
Disclaimer: ALPA has developed this webpage for informational purposes only, and it is not intended to supersede any company training, guidance, or other material. In case of any conflict, company-provided information should be considered to have primacy. If you have any questions, please contact ALPA Engineering and Air Safety at EAS@alpa.org or 800-424-2470.
1. In-Flight Contingency Procedures Change for NAT and NY WATRS Regions
Effective 28 March 2019, the In-Flight Contingency Procedures are changing only for the NAT region and the NY Oceanic West (WATRS) Oceanic Control Areas (OCAs). Contingency procedures in other OCAs remain unchanged.
Per NAT Ops Bulletin 2018_005 Rev 1 dated 13 February 2019, the contingency procedure applies to the following OCAs:
- Gander (CZQX)
- Shanwick (EGGX)
- Santa Maria (LPPO)
- NY Ocean East and NY Ocean West (KZWY)
- Bodø (ENOB)
- Reykjavik (BIRD)
- Nuuk (BGGL)
The following differences should be noted:
A. For en route diversion due to medical emergency, pressurization, equipment failure, or other need for an air turnback, if an ATC clearance cannot be obtained prior to deviation:
- The initial turn from cleared course should be at least 30° (prior procedure was 45°)
- Establish a 5 NM parallel offset from course (prior procedure was 15 NM)
- Minimize altitude loss if possible until established parallel
- Pilots are strongly recommended to descend below FL290 prior to crossing other tracks
B. For in-flight weather deviation when a revised ATC clearance cannot be established, the differences include:
- Maintain cleared flight level if deviation of less than 5 NM is required (prior procedure was 10 NM); otherwise offset altitude according to procedure.
This diagram, courtesy of the Ops Group, summarizes the revised in-flight contingency procedure for the NAT and NY WATRS region:
Pilots are advised to review the entire ICAO Ops Bulletin for the full procedures, and to follow company guidance, procedures, and training for this change to NAT/NY WATRS options.
In addition, pilots should be aware that the revised In-flight contingency procedures are only for the NAT and NY WATRS regions; other OCAs will still use the prior procedure unless otherwise notified by NOTAM or other publication. This may necessitate using different in-flight contingency procedures on the same flight if the flight travels to or from the NAT/NY WATRS region to another OCA.
If you encounter any operational difficulties with these procedures, please contact ALPA Engineering & Air Safety at EAS@alpa.org or 1-800-424-2470.
2. Advanced Surveillance-Enhanced Procedural Separation (ASEPS) Trials
On or about 28 March 2019, the Gander, Shanwick, and Santa Maria OCAs (only) will begin trials of Advanced Surveillance-Enhanced Procedural Separation (ASEPS) based on the use of Space-Based Automatic Dependent Surveillance-Broadcast (ADS-B) reception
Per NAT Ops Bulletin 2018_006 dated 17 December 2018, reduced longitudinal separation may be applied by ATC if the aircraft is equipped and filed as being equipped with:
- ADS-B Out
- Reduced Vertical Separation Minimum (RVSM)/High Level Airspace (HLA) approval
- Controller-Pilot Data Link Communications (CPDLC) meeting Required Communications Performance 240 (RCP 240)
- Automatic Dependent Surveillance-Contract (ADS-C) meeting Required Surveillance Performance 180 (RSP 180)
- Required Navigation Performance 4 (RNP 4)
The reduced longitudinal separations are:
- 17 NM longitudinal (nose-to-tail) separation of aircraft when operating on the same track or when on intersecting tracks with less than 90° relative angle
- 14 NM longitudinal separation of aircraft on intersecting tracks with less than 45° relative angle
- Opposite-direction aircraft on reciprocal tracks may be cleared to climb or descend through flight levels occupied by another aircraft once ADS-B reports passing by 5 NM or more.
In the future, there may be reduced lateral (wingtip-to-wingtip) separation ASEPS trials starting no sooner than six months from the start of longitudinal trials. A further bulletin will be published prior to this next phase.
This trial will run until November 2020, or until the ICAO PANS-ATM is revised to include these procedures.
ALPA members are advised to promptly report any communications, navigation, or surveillance capability failures to ATC when flying in this airspace, and to follow company procedures, guidance, and training for this change to NAT/NY WATRS region operations.
If you encounter any operational difficulties with these procedures, please contact ALPA Engineering & Air Safety at EAS@alpa.org or 1-800-424-2470.
3. Micro-SLOP Procedures in NAT Airspace
The ICAO North Atlantic (NAT) region has used the Strategic Lateral Offset Procedure (SLOP) for several years, to provide additional protection against the effects of a Gross Navigational Error with precision navigation. Until now, SLOP authorized the flight crew to randomly select either a 1.0 or 2.0 NM offset right-of-course.
Effective 7 August, the new “Micro-SLOP” procedure provides additional protection, by authorizing aircraft with capable Flight Management Systems to fly increments of 0.1 NM between 0.0 and 2.0 NM right-of-course.
Micro-SLOP will be rolled-out over time in the NAT and is currently authorized in Gander and Shanwick. There is no operational hazard presented by this phased implementation.
These changes are captured in the ICAO NAT Document 007 rev2019-3, in section 8.5, pp.79-80.
ALPA advises flight crews to follow company guidance for how to apply SLOP and in which airspace to use Micro-SLOP if capable.
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