6.6 North Atlantic, Pacific, RVSM, and Global Navigation Differences

FAA Aircraft Dispatcher Certificate ADX

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1 Chapter 1: Regulations, Certification & Operational Control

1.1 Part 65 Subpart C: Certification, Eligibility & Currency 1.2 Operational Control & Dispatcher-PIC Joint Responsibility 1.3 Domestic, Flag & Supplemental Operations Framework 1.4 Dispatch Release Elements, Signatures & Recordkeeping 1.5 Regulations, Manuals, Crew Qualifications, and Source Control

2 Chapter 2: Atmospheric Physics, Pressure Systems & Fronts

2.1 Atmospheric Structure, Standard Atmosphere & Altimetry 2.2 Air Masses, Frontal Systems & Frontogenesis 2.3 Atmospheric Stability, Lapse Rates & Cloud Formation 2.4 Earth Motion, Regional Weather, Local Winds, and Water Phase Changes

3 Chapter 3: Aviation Weather Hazards & Severe Weather Avoidance

3.1 Structural and Induction Icing: Types, Accretion & Operations 3.2 Thunderstorms, Squall Lines, Microbursts & Low-Level Windshear 3.3 Clear Air Turbulence (CAT), Mountain Waves & Jet Streams 3.4 Low Ceilings, Fog Types & Visibility Restrictions 3.5 Hurricanes, Typhoons, Tornadoes, and Tropical Dispatch Hazards

4 Chapter 4: Weather Observations, Forecasts & Advisories Decoding

4.1 METAR and SPECI Surface Observations: Decoding & Operations 4.2 Terminal Aerodrome Forecasts (TAF): Groups & Timing 4.3 Pilot Weather Reports (PIREP): Coding, Severity & Urgent Alerts 4.4 In-Flight Advisories: AIRMETs, SIGMETs & Convective SIGMETs 4.5 Weather Collection, NWS Facilities, GFA, and EWINS

5 Chapter 5: Aviation Weather Charts & Upper-Air Analysis

5.1 Surface Analysis & Radar Summary Charts 5.2 Constant Pressure Analysis & Winds Aloft (FB) 5.3 Significant Weather Prognostic Charts (SIGWX) 5.4 Satellite Imagery, Moisture-Stability Analysis, and Forecast Integration

6 Chapter 6: Air Navigation, Airspace Architecture & Route Structure

6.1 National Airspace System: Classes, Rules & Special Use 6.2 Ground-Based Navigation Aids & Standard Service Volumes 6.3 Area Navigation (RNAV), GNSS/GPS, PBN & RNP Fundamentals 6.4 En Route Airways, SIDs, STARs & Chart Interpretation 6.5 Earth Coordinates, UTC, Chart Projections, and Flight Instruments 6.6 North Atlantic, Pacific, RVSM, and Global Navigation Differences

7 Chapter 7: Instrument Approaches, Minimums & Airport Operations

7.1 Precision Approach Systems: ILS Categories & Tolerances 7.2 Non-Precision Approaches, RNAV & Decision Minimums (MDA/DA) 7.3 Takeoff Minimums, Lower-Than-Standard & Takeoff Alternates 7.4 Holding Procedures: Patterns, Speed Limits & Timing

8 Chapter 8: Subsonic Aerodynamics & Jet Aircraft Performance

8.1 Subsonic Jet Aerodynamics: Lift, Drag & Flight Regimes 8.2 High-Altitude Flight: Mach Number, Buffet & Coffin Corner 8.3 Transport Turbine Engines: Thrust, Specific Fuel & Bleed Air

9 Chapter 9: Transport Category Takeoff & Landing Runway Analysis

9.1 Takeoff Performance Speeds & Balanced Field Concept 9.2 Takeoff Climb Segments & Obstacle Clearance Gradients 9.3 Landing Performance: Field Lengths, 60% Rule & Contamination

10 Chapter 10: En Route Performance, Driftdown Profiles & ETOPS Operations

10.1 One/Two-Engine-Inoperative En Route Net Profiles & Driftdown 10.2 Extended-Range Operations (ETOPS): Philosophy & Regulations 10.3 ETOPS En Route Alternates: Adequate vs. Suitable & Critical Fuel

11 Chapter 11: Aircraft Weight & Balance, Center of Gravity, and Loading

11.1 Transport Aircraft Structural Weight Limits: Definitions & Rules 11.2 Center of Gravity Computations: Datum, Arm, Moment & Index 11.3 Mean Aerodynamic Chord (%MAC) Computations & Stability 11.4 Payload-Range Analysis, Zero Fuel Weight Tradeoffs & Loading

12 Chapter 12: Destination Alternate Airport Selection & Weather Rules

12.1 Destination Alternate Selection: 91.169 & Part 121 1-2-3 Rule 12.2 Flag & Supplemental Operations Destination Alternate Rules 12.3 Derived Alternate Minimums: 1-Nav and 2-Nav Facility Rules

13 Chapter 13: Part 121 Fuel Planning, Reserves & En Route Re-Release

13.1 Part 121 Domestic Fuel Requirements: Reserves & Calculations 13.2 Part 121 Flag Fuel Requirements: 10% Reserve & Island Rules 13.3 Supplemental Fuel Requirements & Holding Fuel Management 13.4 Redispatch and En Route Re-release Procedures

14 Chapter 14: Transport Systems, Pressurization & MEL/CDL Procedures

14.1 Transport Jet Auxiliary Power, Electrical, Hydraulic & Pneumatic Systems 14.2 Cabin Pressurization, Rapid Decompression & Oxygen Requirements 14.3 Master Minimum Equipment List (MMEL), MEL & CDL Procedures 14.4 Flight Controls, Autoflight, Fuel, Oil, Brakes, and Fire Protection

15 Chapter 15: Hazardous Materials, Duty Regulations & Emergency Procedures

15.1 Dangerous Goods Carriage by Air (49 CFR Part 175) & NOTOC 15.2 Dispatcher Duty Limitations, Rest Requirements & Fatigue 15.3 Emergency Authority, Declaration & Diversion Decision-Making 15.4 NTSB Part 830 Accident Reporting & Wreckage Preservation 15.5 Security, Overdue Aircraft, and FAA Emergency Services

16 Chapter 16: Communications, ATC, and Flight Plan Procedures

16.1 Voice, Data Link, Position Reports, and Lost Communications 16.2 ATC Facilities, Separation, ICAO Flight Plans, and Traffic Management

17 Chapter 17: Human Factors and Practical Dispatch Applications

17.1 Dispatch Resource Management, Human Error, and Risk Decisions 17.2 Manual Flight Planning, PIC Briefing, Flight Watch, and Postflight Closeout

6.6 North Atlantic, Pacific, RVSM, and Global Navigation Differences

Key Takeaways Explain This Topic AI

AC 91-70C supplies general oceanic/remote guidance; current regional AIPs and issued authority govern the actual procedure.

RNAV/RNP, CPDLC, ADS-C, and PBCS describe different capabilities and approvals.

RVSM generally covers FL290–FL410 inclusive in designated airspace for eligible operations.

U.S. 18,000-foot pressure-setting conventions are not universal worldwide.

MEL dispatchability for a domestic flight does not prove oceanic or reduced-separation eligibility.

Last updated: October 2026

Oceanic Planning Requires Regional Authority

A domestic IFR release does not automatically establish authorization for an oceanic or remote route. Appendix A explicitly names the North Atlantic, Pacific, and global differences. FAA AC 91-70C provides current general guidance and directs operators to the relevant regional resources and published information. Use current AIPs, NOTAMs, issued OpSpecs, aircraft approvals, and carrier procedures for the actual flight.

Start with capabilities and limitations

Verify the required navigation, communication, surveillance, altimetry, and crew qualifications before selecting the route. RNAV/RNP describes navigation performance; CPDLC is controller–pilot data-link communication; ADS-C is contract-based surveillance reporting; and PBCS addresses performance-based communication/surveillance. They are not interchangeable authorizations.

A route requiring a specific data-link approval cannot be accepted simply because ACARS text messages reach dispatch. A GNSS receiver's operation does not prove compliance with every long-range-navigation redundancy requirement. Check the actual aircraft configuration, equipment status, database, navigation specification, and issued authority. An MEL defect may permit domestic flight while removing the intended oceanic or reduced-separation capability.

North Atlantic considerations

The North Atlantic uses regional high-level-airspace procedures, organized tracks where published, and random-route options under applicable conditions. Track information has specific validity periods and identification. Verify the current track, level, speed and applicable navigation/data-link requirements. A route copied from yesterday's release can be wrong even if its airports are unchanged.

Clearance procedures have changed in parts of the region over time. Do not assume that every oceanic control area requires the same separate pre-entry clearance transaction. Read the current regional AIP and operating instructions for each boundary. Coordinate the planned and cleared route, including entry/exit points, with the actual aircraft and crew authorizations.

Pacific and remote continental differences

Pacific routes can involve long distances between suitable diversion airports, different communication coverage, organized-route arrangements where applicable, and substantial weather or volcanic-ash exposure. The regional AIPs and FAA Pacific resources define applicable procedures. A North Atlantic mnemonic must not be imposed unchanged on a Pacific control area.

For a remote continental route, navigation and communication coverage can also be sparse even though the flight is over land. High terrain, extreme cold, limited airport support, and rescue considerations can dominate the diversion plan. Oceanic/remote operational approval and ETOPS planning are related checks but neither alone proves terrain clearance, oxygen duration, or diversion-airport availability.

RVSM

Reduced Vertical Separation Minimum (RVSM) generally uses 1,000-foot separation from FL290 through FL410 inclusive in designated RVSM airspace for eligible, authorized operations. Aircraft altimetry, altitude-keeping equipment, required operating practices, and operator/crew eligibility matter. The existence of a working primary altimeter does not by itself establish RVSM eligibility.

If required equipment fails or the crew cannot maintain the required altitude performance, follow the applicable notification and contingency procedure and coordinate an appropriate ATC response. Dispatch assesses route, weather, fuel, and any alternate level outside RVSM where needed. Do not assume an airplane may stay at its requested level simply because the release was originally RVSM-capable.

Position and waypoint verification

Oceanic position errors can arise from coordinate entry, wrong hemisphere, mismatched waypoints, navigation drift, or an automation/database issue. Compare the active route with the authorized route using independent checks. Verify longitude/latitude formats and the current reference for courses, particularly where magnetic compasses become less reliable at high latitude.

Before and after a navigation boundary, review required position reporting and data-link logon arrangements. A correct navigation display is not evidence that the receiving ATC system has accepted a logon or is receiving reports. Monitor system status and obtain confirmation under approved procedures. A transmission can be sent without completing the communication loop.

Global altimetry and airport information

The U.S. 18,000-foot transition convention is not universal worldwide. Other jurisdictions publish transition altitudes/levels and their pressure-setting procedures. QNH refers to the pressure setting relating altitude to mean sea level; QFE , where used, references height to the specified field datum. Units can also differ, including hPa versus inHg and meters versus feet in some operational information.

• Global difference Dispatch crosscheck
• Pressure setting and units Published transition procedure and crew/aircraft capability
• Runway/approach data Current regional publications, language and units
• Navigation specification Actual route/procedure requirement and issued authority
• Data link / voice Required systems, coverage, approval, and contingencies
• Airport services Hours, field reports, rescue support, and diversion suitability
• Communications and contingencies

HF, VHF, satellite voice, CPDLC, and other approved links serve different functions and coverage areas. ETOPS flag communication requirements in § 121.99 include specific voice/additional-system provisions. Availability must be evaluated for possible diversion routes and altitudes, not only the planned high cruise level. A text-only company link does not demonstrate compliance with every required voice system.

For weather deviation, navigation failure, depressurization, or inability to obtain a revised clearance, crews use the current applicable regional contingency procedure and aircraft instructions. Strategic lateral offsets and emergency offsets have specified applicability and are not a universal instruction to turn a fixed direction or distance in all airspace. Dispatch assists with alternate suitability, fuel, terrain, weather, and notifications while ATC and the PIC handle the actual clearance and aircraft maneuver.

Worked authorization check

A fictional aircraft has an MEL defect that removes one required navigation source. Its original long-haul route depends on an approval whose equipment condition is no longer met. The dispatcher evaluates another permitted route or aircraft, then recomputes diversion coverage, critical fuel, winds, terrain/oxygen, and weather windows. The correct answer is not to retain the route because the remaining FMS shows accurate position today. The released flight must satisfy the actual route's authorization and capability requirements, with current regional information and documented crew concurrence.

Official References

Source check: 2026-10-12 . FAA AIM navigation guidance ; FAA aeronautical handbooks and current addenda ; Current AC 91-70 oceanic guidance . For operational use, apply current issued authorizations and the assigned aircraft’s approved data.