AC 91-70D

Advisory circular · Oceanic and Remote Continental Airspace Operations

Approved
April 3, 2025
Last reviewed
April 9, 2025
Cancels
AC91-70C
Family
AC 91-70 · 6 versions
Revision
D
14 CFR parts
91, 119, 121, 125, 135

Guidance, not mandatory unless a rule or AD requires it. DRS record last changed November 22, 2025.

Show pages 120–131
Page 132Open in PDF

Appendix G G-3 G.3.4 Operational Flight Plan (also known as Computer Flight Plan (CFP)):

• Comparison to ATC flight plan.

• Basic cross checks (fuel, groundspeed, winds).

• Equal Time Point (ETP) and points of safe return.

• Fuel requirements (in particular, ICAO Annex 6) and reduced fuel (B043, B044, and B343 authorizations).

G.3.5 Special Area of Operation (SAO) Requirements.

G.3.6 Use of Plotting/Orientation Chart and Master Document.

G.3.7 Weather Radar (WX) Charts:

• Terminal Aerodrome Forecast (TAF), Aviation Routine Weather Report (METAR), and Significant Weather (SIGWX).

• 700 millibars (mb), 500 mb, 400 mb, 300 mb, 250 mb.

• Approved source(s): National Weather Service (NWS) and Enhanced Weather Information System (EWINS).

G.3.8 Driftdown—Terrain, Alternates, Extended Operations (ETOPS).

G.3.9 World Geodetic System 1984 (WGS 84) or Approved Equivalent Compliance.

G.4 State Operating Restrictions.

G.5 Reduced Vertical Separation Minimum (RVSM):

• General description.

• Metric assignments (e.g., China).

• Minimum required equipment.

• Contingencies.

• Forecasts, tropopause, temperature deviations.

G.6 Accident/Incident.

G.6.1 Title 49 of the Code of Federal Regulations (49 CFR):

• Part 175, Carriage by Aircraft (Hazardous Materials (HAZMAT) Regulations).

• Part 830, Notification and Reporting of Aircraft Accidents or Incidents and Overdue Aircraft, and Preservation of Aircraft Wreckage, Mail, Cargo, and Records (National Transportation Safety Board (NTSB)).

Page 133Open in PDF

Appendix G G-4 G.6.2 Contingencies:

• Weather deviations.

• General contingencies.

• Lost communications, traffic information broadcasts by aircraft (TIBA), In-Flight Broadcast Procedure (IFBP).

• Degraded navigation, dead reckoning.

• Activation of Automated Mutual-assistance Vessel Rescue (AMVER) system, emergency locator transmitter (ELT).

• Depressurization/oxygen supply.

• Intercept, hijack.

G.6.3 Use of Navigation System:

1. Review of Airplane Flight Manual Supplements (AFMS) for capabilities/limitations.

2. Description of GPS, GPS NOTAMs, receiver autonomous integrity monitoring (RAIM) prediction, fault detection and exclusion (FDE).

3. Description of inertial navigation system (INS), time limits.

4. Currency/software version of database.

5. Loading, updating, and cross-checks:

• Format for manual entry into the flight management system (FMS) of latitude/longitude waypoints.

• Methods for entering time or “line-of-longitude” constraints (e.g., “at 1210 climb to FL 340” or “cross 16W level at FL 340”).

• How to “expand” waypoints to display full latitude and longitude.

6. Independent verification.

7. Contingencies/fault codes.

G.6.4 Oceanic Crossing:

• Oceanic checklist (see Appendix D, Sample Oceanic Checklist).

• Master time source.

• Clearance-flight information region (FIR) differences.

• Navigation accuracy check (as applicable).

• RVSM checks.

• Approaching, overhead, and post-position waypoint checks.

Page 134Open in PDF

Appendix G G-5

• Position report—estimated time of arrival (ETA) tolerance.

• Five-minute post-position check.

G.6.5 Altimetry:

• QNH, QNE, and QFE.

• Transition altitude (TA)/transition level (TL).

• Millibars (mb), hectopascals (hPa).

G.6.6 Transponder Operations. Regional (e.g., NAT, Pacific) requirements.

G.6.7 Communications, Navigation, and Surveillance.

• Airspace requirements (RNP 10/4/2).

• Data link (ADS-C, CPDLC).

• Voice communications and aeronautical radio stations (very high frequency (VHF), high frequency (HF), Satellite Voice (SATVOICE)).

• Reduced separation—trials and implementations.

G.6.8 Strategic Lateral Offset Procedures (SLOP).

G.6.9 Volcanic Ash. Source of information and crew notification.

G.6.10 Space Weather. Warnings, alerts, and advisories (see Appendix C, Unusual Weather Activity).

G.6.11 Operational Control:

• A008 authorization.

• A009 authorization.

• A010 authorization.

G.6.12 Oceanic Speed Control:

• Tolerance, areas applicable.

• ATC Mach Number Technique.

• Operations Without Assigned Fixed Speed (OWAFS).

G.6.13 Oceanic Errors:

• Revised clearance/conditional clearances.

• CPDLC route clearances.

Page 135Open in PDF

Advisory Circular Feedback Form If you find an error in this AC, have recommendations for improving it, or have suggestions for new items/subjects to be added, you may let us know by contacting the Flight Technologies and Procedures Division or the Flight Standards Directives Management Officer at 9-AWA- AFB-120-Directives@faa.gov.

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