AC 91-70B

Historical

Advisory circular · Oceanic and Remote Continental Airspace Operations

A newer version is currentThis is a historical version. AC 91-70D is the version in force, approved April 3, 2025.
Approved
October 4, 2016
Last reviewed
August 2, 2024
Cancels
AC91-70A
Cancelled by
AC91-70B CHG 1
Family
AC 91-70 · 6 versions
Revision
B
14 CFR parts
91, 119, 121, 125, 135

Guidance, not mandatory unless a rule or AD requires it. DRS record last changed November 21, 2025.

Show pages 100–111
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Appendix E

2. Ensure that their charts and flight documentation are fully amended to reflect the foregoing.

E.9.1 Any operator reported to LATA as not applying the procedure must be contacted immediately, informed of the procedure, and requested to apply it.

E.9.2 Attention is drawn to the fact that during the Haj pilgrimage period the number of east-west flights in the north-central part of the AFI region increases dramatically, and with it the risk of ATS incidents and therefore the importance of the IFBP.

E.10 Review. The procedure and its area of applicability are reviewed by the IATA AFI Regional Coordination Group from time to time. The list of FIRs in which you should apply the procedure may be modified as necessary.

Figure E-1. Map of IFBP Area of Applicability Source: IATA SO&I AFI 20° 10°

ALGIERS TRIPOLI CAIRO

CANARIES JEDDAH DAKAR

SAL OCEANIC NIAMEY ASMARA

N'DJAMENA

KHARTOUM KANO AREA OF APPLICABILITY MOGADISHU 10°

ADDIS ABEBA

BRAZZAVILLE -g= DAKAR OCEANIC ACCRA *ENTEBBE

KINSHASA -RIGALL NAIROBI SEYCHELLES

• BUJUMBURA (DAR-ES-SALAAM)

•10° 10°- LUANDA

MAURITIUS

ATLANTICO 20° WINDHOEK BEIRA 20°

GABORONE NARIVO

JOHANNESBURG OCEANIC

JOHANNESBURG 30°-

CAPE TOWN JOHANNESBURG OCEANIC _20° 30 40 9 January 2014 E-4

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Appendix F APPENDIX F. SPECIAL PROCEDURES FOR IN-FLIGHT CONTINGENCIES IN

OCEANIC AND REMOTE CONTINENTAL AIRSPACE F.1 Introduction. Although all possible contingencies cannot be covered, these procedures provide for the more frequent cases such as:

• Inability to comply with assigned clearance due to meteorological conditions, aircraft performance, or pressurization failure.

• En route diversion across the prevailing traffic flow.

• Loss of, or significant reduction in, the required navigation capability when operating in airspace where the navigation performance accuracy is a prerequisite to the safe conduct of flight operations.

F.1.1 The procedures are applicable primarily when descent and/or turn back or diversion is required. The pilot shall take action as necessary to ensure the safety of the aircraft, and the pilot’s judgment shall determine the sequence of actions to be taken, having regard to the prevailing circumstances. Air traffic control (ATC) shall render all possible assistance.

F.2 General Procedures.

Note: There may be regional differences in these general procedures.

Paragraph 7.2.1 explains. You should be familiar with the planning and guidance documents pertinent to the airspace in which you will be operating.

F.2.1 If an aircraft is unable to continue the flight in accordance with its ATC clearance and/or is unable to maintain the navigation performance accuracy specified for the airspace, a revised clearance shall be obtained, whenever possible, prior to initiating any action.

F.2.2 The radiotelephony distress signal (“MAYDAY”) or urgency signal (“PAN PAN”), preferably spoken three times, shall be used as appropriate. Subsequent ATC action with respect to that aircraft shall be based on the intentions of the pilot and the overall air traffic situation.

F.2.3 If deviation is required and prior clearance cannot be obtained, the following contingency procedures should be employed until such time a revised clearance is received. Advise ATC as soon as practicable, reminding them of the type of aircraft involved and the nature of the problem. In general terms, the aircraft should be flown at a flight level (FL) and on an offset track where other aircraft are least likely to be encountered. Specifically, the pilot shall:

F-1

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Appendix F F.2.3.1 Leave the assigned route or track by initially turning at least 45° to the right or left, in order to acquire a same or opposite direction track offset 15 nautical miles (NM) (28 km) from the assigned track centerline. When possible, the direction of the turn should be determined by the position of the aircraft relative to any organized route or track system. Other factors which may affect the direction of the turn are:

1. The direction to an alternate airport.

2. Terrain clearance.

3. Any strategic lateral offset being flown.

4. The FLs allocated on adjacent routes or tracks.

F.2.3.2 Having initiated the turn:

F.2.3.2.1 If unable to maintain the assigned FL, initially minimize the rate of descent to the extent that is operationally feasible. Pilots should take into account the possibility that aircraft below on the same track may be flying a 1 or 2 NM Strategic Lateral Offset Procedure (SLOP) and select a final altitude which differs from those normally used by 500 ft. (150 m) if at or below FL 410, or by 1,000 ft. (300 m) if above FL 410; or F.2.3.2.2 If able to maintain the assigned FL, once the aircraft has deviated 10 NM (19 km) from the assigned track centerline, climb or descend to select a flight level which differs from those normally used by 500 ft. (150 m), if at or below FL 410, or by 1,000 ft (300m) if above FL 410.

F.2.3.3 Establish communications with and alert nearby aircraft by broadcasting, at suitable intervals, on 121.5 megahertz (MHz) (or, as a backup, on the inter-pilot air-to-air frequency 123.45 MHz) and where appropriate on the frequency in use: aircraft identification, FL, position (including the Air Traffic Service (ATS) route designator or the track code, as appropriate) and intentions.

F.2.3.4 Maintain a watch for conflicting traffic both visually and by reference to the Airborne Collision Avoidance System (ACAS).

F.2.3.5 Turn on all aircraft exterior lights (commensurate with appropriate operating limitations).

F.2.3.6 Keep the Secondary Surveillance Radar (SSR) transponder on at all times.

F.2.4 When leaving the assigned track:

F.2.4.1 If the intention is to acquire a same direction offset track, the pilot should consider limiting the turn to a 45° heading change, in order not to overshoot the offset contingency track.

F-2

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Appendix F F.2.4.2 If the intention is to acquire and maintain an opposite direction offset track, then:

F.2.4.2.1 Operational limitations on bank angles at cruising altitudes will normally result in overshooting the track to be acquired. In such cases a continuous turn should be extended beyond 180° heading change, in order to re-intercept the offset contingency track as soon as operationally feasible.

F.2.4.2.2 Furthermore, if executing such a turn back in a 30 NM (56 km) lateral separation route structure, extreme caution pertaining to opposite direction traffic on adjacent routes must be exercised and any climb or descent, as specified in paragraph F.2.3.2.2, should be completed preferably before approaching within 10 NM (19 km) of any adjacent ATS route.

F.3 General Weather Deviation Procedures. The following procedures are intended for deviations around adverse meteorological conditions.

F.3.1 When the pilot initiates communications with ATC, a rapid response may be obtained by stating “WEATHER DEVIATION REQUIRED” to indicate that priority is desired on the frequency and for ATC response. When necessary, the pilot should initiate the communications using the urgency call “PAN PAN” (preferably spoken three times).

F.3.2 The pilot should notify ATC and request clearance to deviate from track, advising when possible, the extent of the deviation expected.

F.3.3 ATC should take one of the following actions:

F.3.3.1 When appropriate separation can be applied, issue clearance to deviate from track.

F.3.3.2 If there is conflicting traffic and ATC is unable to establish appropriate separation, ATC shall:

1. Advise the pilot of inability to issue clearance for the requested deviation.

2. Advise the pilot of conflicting traffic.

3. Request the pilot’s intentions.

F.3.4 The pilot should take one of the following actions:

1. Comply with the ATC clearance issued; or

2. Advise ATC of intentions and execute the procedures detailed in paragraph F.3.5 below.

F.3.5 Actions to be taken if a revised ATC clearance cannot be obtained:

F-3

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Appendix F Note: These provisions apply to situations where a pilot needs to exercise the authority of a pilot in command (PIC) under the provisions of International Civil Aviation Organization (ICAO) Annex 2, paragraph 2.3.1.

F.3.5.1 If the aircraft is required to deviate from track to avoid adverse meteorological conditions and prior clearance cannot be obtained, an ATC clearance shall be obtained at the earliest possible time. Until an ATC clearance is received, the pilot shall take the following actions:

F.3.5.1.1 If possible, deviate away from an organized track or route system.

F.3.5.1.2 Establish communications with and alert nearby aircraft by broadcasting, at suitable intervals: aircraft identification, FL, position (including ATS route designator or the track code) and intentions, on the frequency in use and on 121.5 MHz (or, as a backup, on the inter-pilot air-to-air frequency

123.45 MHz).

F.3.5.1.3 Watch for conflicting traffic, both visually and by reference to ACAS.

Note: If, as a result of actions taken under the provisions of items F.3.5.1.2 and F.3.5.1.3 above, the pilot determines that there is another aircraft at or near the same FL with which a conflict may occur, then the pilot is expected to adjust the path of the aircraft, as necessary, to avoid conflict.

F.3.5.1.4 Turn on all aircraft exterior lights (commensurate with appropriate operating limitations).

F.3.5.1.5 For deviations of less than 10 NM (19 km), remain at a level assigned by ATC.

F.3.5.1.6 For deviations greater than 10 NM (19 km), when the aircraft is approximately 10 NM (19 km) from track, initiate a level change in accordance with Figure F-1, General Weather Deviation Procedures Model.

F.3.5.1.7 When returning to track, be at the assigned FL when within approximately 10 NM (19 km) of the centerline.

F.3.5.1.8 If contact was not established prior to deviating, continue to attempt to contact ATC to obtain a clearance. If contact was established, continue to keep ATC advised of intentions and obtain essential traffic information.

F.3.6 The pilot shall inform ATC when weather deviation is no longer required, or when a weather deviation has been completed and the aircraft has returned to its cleared route.

F-4

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Appendix F Figure F-1. General Weather Deviation Procedures Model 359° 0° Deviate Right > 10 nm Deviate Left ≥ 10 nm

• Descend 300° * Descend 300' Route Centre Line Deviate < 10 nm Deviate ≤ 10 nm Route Centre Line Track 180° - 359° (magnetic) Remain Level Remain Level Track 0° - 179° (magnetic) Deviate Left > 10 nm Deviate Right ≥ 10 nm † Climb 300° † Climb 300° 180° 179° F-5

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Appendix G APPENDIX G. SUGGESTED SUBJECTS FOR INCLUSION IN OCEANIC AND

INTERNATIONAL PROCEDURES AND/OR AN OPERATIONS MANUAL Note 1: This list is for reference only. It is not intended to be all inclusive.

You are encouraged to use this sample when creating procedures and/or operations manuals and keeping them current. Your complexity of operations and operational approvals will dictate which items on this list are applicable or need to be expanded. Please see the NAT PDF, PAC PDF, or WATRS PDF for the most current version of this list.

Note 2: You should establish and maintain a robust process to remain current in Oceanic and International Operations. This continuous analysis or process is one component of an operator’s Safety Management System (SMS).

G.1 Regulations, International Civil Aviation Organization (ICAO) Guidance, and References.

G.1.1 Title 14 of the Federal Code of Regulations (14 CFR).

G.1.2 Applicable ICAO Documents (current editions):

1. ICAO Document 4444, Procedures for Air Navigation Services—Air Traffic Management (PANS-ATM).

2. ICAO Document 10037, Global Operational Data Link Operation (GOLD) (Controller-Pilot Data Link Communication (CPDLC), Automatic Dependent Surveillance-Contract (ADS-C)).

3. ICAO Document 7030, Regional Supplementary Procedures.

4. ICAO Document 9574, Manual on a 300 m (1000 ft) Vertical Separation Minimum Between FL 290 and FL 410 Inclusive.

5. ICAO Document 9613, Performance Based Navigation (PBN) Manual.

6. ICAO Annex 2, Rules of the Air.

7. ICAO Annex 6, Operation of Aircraft (Parts I, II, and III as applicable).

8. ICAO NAT Document 007, North Atlantic Operations and Airspace Manual.

G.1.3 Aeronautical Information Publication (AIP), United States of America—Relevant Material.

G.1.4 Applicable Federal Aviation Administration (FAA) Advisory Circulars (AC), Orders, and Notices (current editions):

1. AC 90-96, Approval of U.S. Operators and Aircraft to Operate Under Instrument Flight Rules (IFR) In European Airspace Designated for Basic Area Navigation (B-RNAV)/RNAV 5 and Precision Area Navigation (P-RNAV).

G-1

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Appendix G

2. AC 90-105, Approval Guidance for RNP Operations and Barometric Vertical Navigation in the U.S. National Airspace System and in Oceanic and Remote Continental Airspace.

3. AC 91-70, Oceanic and Remote Continental Airspace Operations.

4. AC 91-85, Authorization of Aircraft and Operators for Flight in Reduced Vertical Separation Minimum Airspace.

5. AC 120-42, Extended Operations (ETOPS and Polar Operations).

6. AC 135-42, Extended Operations (ETOPS) and Operations in the North Polar Area.

G.1.5 Miscellaneous.

1. FAA NAT PDF, PAC PDF, RNP PDF, ICAO Paris, and Eurocontrol (SKYbrary).

2. State Department Travel Alerts and Transportation Safety Administration (TSA) Alerts.

G.1.6 Notices to Airmen (NOTAM) and Special Federal Aviation Regulations (SFAR).

G.2 Navigation. Class I versus Oceanic and Remote and dead reckoning (DR).

G.3 Flight Planning.

G.3.1 North American Routes (NAR).

G.3.2 Track Messages.

G.3.3 ICAO FPs. Explanation and correct codes.

G.3.4 Computer FP.

1. Comparison to ICAO FP.

2. Basic cross checks (fuel, groundspeed (GS), winds).

3. Equal time points (ETP) and points of safe return (PSR).

4. Fuel requirements (in particular ICAO Annex 6) and reduced fuel (Operations Specifications (OpSpec) B043, B044, and B343).

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

G.3.6 Use of Plotting/Orientation Chart and Journey Log.

G.3.7 WX Charts.

1. Terminal Aerodrome Forecast (TAF), Aviation Routine Weather Report (METAR), and significant weather (SIGWX).

G-2

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Appendix G

2. 700 millibars (MB), 500 MB, 400 MB, 300 MB, 250 MB.

3. Approved source(s)—National Weather Service (NWS) and Enhanced Weather Information System (EWINS).

G.3.8 Drift Down—Terrain, Alternates, ETOPS.

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

G.4 State Operating Restrictions (e.g., Cabotage).

G.5 Reduced Vertical Separation Minimum (RVSM).

1. General description.

2. Metric assignments (e.g., China versus Russia).

3. Minimum required equipment.

4. Contingencies.

5. Forecasts, tropopause, temperature deviations.

G.6 Accident/Incident.

G.6.1 Title 49 of the Code of Federal Regulation (49 CFR) Part 830 (National Transportation Safety Board (NTSB)) and Part 175 (Hazardous Materials Regulations (HMR).

G.6.2 Contingencies.

1. Weather deviations.

2. Fifteen nautical miles (NM) offset.

3. Lost Communications/Navigations, In-Flight Broadcast Procedures (IFBP), Automated Mutual-assistance Vessel Rescue System (AMVER), Oxygen.

4. Intercept, hijack.

G.6.3 Use of Long-Range Navigation Systems (LRNS)/Flight Management Systems (FMS).

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

2. Description of Global Positioning System (GPS)/Inertial.

3. Currency/software version of database.

4. Loading and cross-checks.

5. Independent verification.

6. Contingencies/fault codes.

G-3

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Appendix G G.6.4 Oceanic Crossing.

1. Oceanic checklist (Appendix D).

2. Master time source.

3. Clearance-Flight Information Region (FIR) differences.

4. Navigation accuracy check.

5. RVSM checks.

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

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

8. Ten-minute post-position check.

G.6.5 Altimetry.

1. Barometric Pressure for Local Altimeter Setting (QNH), Barometric Pressure for Standard Altimeter Setting (QNE), and Atmospheric Pressure at Aerodrome Elevation (QFE).

2. Transition Altitude (TA)/Transition Level (TL).

3. MB, Hectopascals.

G.6.6 Transponder Operations. Regional requirements.

G.6.7 Communication, navigation, and surveillance.

1. Airspace requirements (RNP 10/5/4/1).

2. Data link (ADS-C, CPDLC).

3. Reduced separation—trials and implementations.

G.6.8 Strategic Lateral Offset Procedure (SLOP).

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

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

G.6.11 Operational Control.

1. OpSpec A008—Operational Control.

2. OpSpec A009—Airport Aeronautical Data.

3. OpSpec/MSpec A010—Aviation Weather Information.

G-4

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Appendix G G.6.12 Mach Number Technique.

1. Tolerance.

2. Areas applicable.

G.6.13 Oceanic Errors.

1. Oceanic Errors Safety Bulletin (OESB).

2. Reclearance/conditional clearances.

G-5