7-2 Note 1: In 2020, ICAO changed the lateral offset values in oceanic contingency procedures to 5 nautical miles (NM). For the general procedures, acquire the 5 NM offset before changing altitude. For the weather contingency procedures, adjust altitude by 300 ft (climb or descend, per the procedures) only when deviating 5 NM or more.
Note 2: Whenever possible, obtain a revised clearance instead of flying a contingency procedure. If the nature of the emergency precludes this, consider querying ATC about safest routes, even if ATC is unable to clear you that way.
7.2.2 General and Weather Deviation Contingency Procedures. A “General” contingency procedure is available, as is a weather deviation procedure. Flightcrews should be thoroughly familiar with these procedures and ensure ready access to them on the flight deck so they may be performed precisely and without undue delay.
7.2.2.1 The general procedure results in a 5 NM lateral offset, at an altitude of 500 or 1,000 feet “different from those normally used.” It is reprinted in Appendix F, Special Procedures for In-Flight Contingencies in Oceanic Airspace.
7.2.2.2 The weather deviation procedure results in an altitude change of 300 feet, to be applied when the lateral deviation reaches 5 NM from the centerline. It is also reprinted in Appendix F.
7.3 Altimetry and/or Navigation Degradation. You must notify the Air Traffic Service (ATS) Provider (ATSP) as soon as possible if your altimetry and/or navigation systems have degraded below that required to operate in Reduced Vertical Separation Minimum (RVSM), Required Navigation Performance (RNP), or Area Navigation (RNAV) airspace. In general, that notification, either via voice or Controller-Pilot Data Link Communications (CPDLC), will include the phrase “UNABLE RNP (OR RNAV OR RVSM) DUE EQUIPMENT.”
7.3.1 Whenever possible, you should request a revised clearance that accounts for the degradation you have experienced. Upon receipt of your message, ATSPs will assess the traffic situation and either allow you to remain as filed or issue a reroute, depending on your current (and projected future) separation from other traffic.
7.3.2 For navigation degradation scenarios, dead reckoning procedures may be required.
Flightcrews should be familiar with determining heading and leg time required, through the use of the Master Document, the chart, and/or Electronic Flight Bag (EFB) applications.
Note: ICAO NAT Doc 007, North Atlantic Operations and Airspace Manual, provides specific procedures to be used in the North Atlantic (NAT) in the event of navigation system degradation or failure.
7.4 Lost Communications Procedures. The general rules for lost communications are captured in ICAO Annex 2, Rules of the Air, Chapter 3, General Rules, and are included in their entirety in ICAO Doc 4444, Section 15.3, Air-Ground Communications Failure.
7-3 Prior to departure, ensure you are familiar with the lost communications rules for the regions you are transiting.
7.4.1 Region-Specific Rules. In some regions, ATS authorities have amended the rules to meet their specific air traffic management (ATM) requirements. These amended rules are included in ICAO Doc 7030, generally in chapter 9 of the applicable region’s section.
ICAO NAT Doc 007 also provides a detailed discussion of lost communications procedures specific to NAT airspace. Refer also to the FAA’s International Notices web page, which will include any changes or regional applications to lost communications procedures.
7.4.1.1 Generally, ATS authorities expect you to maintain your last assigned speed and altitude for some period (usually 20 minutes or 60 minutes, depending on the region), then adjust your speed and altitude to conform to your flight plan.
7.4.1.2 In the NAT region, you are expected to fly your ATC-cleared routing, FL, and airspeed through oceanic airspace, picking up your filed flight plan route after passing the oceanic exit point.
7.4.2 Unexpected Closure of an Oceanic ATC Facility. See Appendix F, paragraph F.4 for considerations in the event of an oceanic ATC facility shutdown.
7.5 Normal Aircraft Tracking. ICAO, in Annex 6, Operation of Aircraft, Part I, International Commercial Air Transport—Aeroplanes, Section 3.5, Aircraft Tracking, established a requirement for an automated four dimensional (4D) (latitude, longitude, altitude, and time) tracking capability for oceanic operations involving aircraft above a certain weight and seating capacity. The FAA recommends all operators establish some automated capability to track the position of their aircraft during oceanic operations using a means that does not require direct flightcrew action. ICAO Circular 347, Aircraft Tracking Implementation Guidelines, provides additional information.
Appendix A A-1 APPENDIX A. ABBREVIATIONS AND DEFINITIONS A.1 Abbreviations.
Acronym Description 14 CFR Title 14 of the Code of Federal Regulations 4D Four Dimensional AC Advisory Circular ACARS Aircraft Communications Addressing and Reporting System ACAS Airborne Collision Avoidance System (same as TCAS) ACC Area Control Center ACID Aircraft Identification ADIZ Air Defense Identification Zone ADS Automatic Dependent Surveillance (in older documents published before ADS-B existed, “ADS” generally refers to ADS-C) ADS-B Automatic Dependent Surveillance-Broadcast ADS-C Automatic Dependent Surveillance-Contract AFI African-Indian Ocean Region (per ICAO) AIM Aeronautical Information Manual AIP Aeronautical Information Publication AMU Area of Magnetic Unreliability AMVER Automated Mutual-assistance Vessel Rescue ANP Actual Navigation Performance APR Automatic Positioning Reporting ARTCC Air Route Traffic Control Center ATA Actual Time of Arrival ATC Air Traffic Control ATM Air Traffic Management ATOP Advanced Technologies and Oceanic Procedures ATS Air Traffic Service ATSP Air Traffic Service Provider CAA Civil Aviation Authority CEP Central East Pacific
Appendix A A-2 Acronym Description CFP Computer Flight Plan CPDLC Controller-Pilot Data Link Communications CTA Control Area DME Distance Measuring Equipment DOS Department of State EDTO Extended Diversion Time Operations EFB Electronic Flight Bag ELOS Equivalent Level of Safety ETA Estimated Time of Arrival ETE Estimated Time En Route ETOPS Extended Operations ETP Equal Time Point EWINS Enhanced Weather Information System FAA Federal Aviation Administration FANS 1/A Future Air Navigation System 1/A (1=Boeing; A=Airbus) FDE Fault Detection and Exclusion FIR Flight Information Region FIS Flight Information Services FL Flight Level FLT ID Flight Identification FMC Flight Management Computer FMS Flight Management System FRMS Fatigue Risk Management System GA General Aviation GNE Gross Navigation Error GNSS Global Navigation Satellite System GOLD Global Operational Data Link Document GPS Global Positioning System H2S Hydrogen Sulfide HF High Frequency HLA High Level Airspace
Appendix A A-3 Acronym Description hPa Hectopascal IAP Instrument Approach Procedure IATA International Air Transport Association ICAO International Civil Aviation Organization IFBP In-Flight Broadcast Procedure IFR Instrument Flight Rules ILS Instrument Landing System IMC Instrument Meteorological Conditions inHg Inch of Mercury INS Inertial Navigation System IRS Inertial Reference System LHD Large Height Deviation LNAV Lateral Navigation LOA Letter of Authorization LRC Long Range Cruise LRCS Long-Range Communication System LRNS Long-Range Navigation System MEA Minimum En Route Altitude MEL Minimum Equipment List MHz Megahertz MMEL Master Minimum Equipment List Mode S Mode Select Secondary Radar With Data Link MSpecs Management Specifications NAS National Airspace System NAT North Atlantic NAT HLA North Atlantic High Level Airspace NATO North Atlantic Treaty Organization NAV Navigation NAVAID Navigational Aid NavSpec Navigation Specification NDA Northern Domestic Airspace
Appendix A A-4 Acronym Description NDB Nondirectional Beacon NM Nautical Miles NOAA National Oceanic and Atmospheric Administration NOPAC North Pacific NOTAM Notice to Airmen NWS National Weather Service OAPS Operations Approval Portal System OCA Oceanic Control Area OESB Oceanic Errors Safety Bulletin OpSpecs Operations Specifications OROCA Off-Route Obstruction Clearance Altitude OTS Organized Track System PANS Procedures for Air Navigation Services PANS-ATM Procedures for Air Navigation Services—Air Traffic Management (ICAO Doc 4444) PANS-OPS Procedures for Air Navigation Services—Aircraft Operations (ICAO Doc 8168) PBC Performance-based Communication PBCS Performance-based Communication and Surveillance PBN Performance-based Navigation PI Principal Inspector PIC Pilot in Command PIREP Pilot Weather Report POI Principal Operations Inspector PPO Prior Permission Only QFE Atmospheric pressure at aerodrome elevation (or at runway threshold).
(With the runway threshold QFE set in the subscale, your altimeter will read zero on the runway threshold.)
QNE Pressure Altitude (Flight Level), obtained with Standard Pressure
(29.92 inches of mercury (inHg) or 1013.2 hPa) set in the altimeter subscale.
QNH The pressure set on the subscale of the altimeter so that the instrument indicates its height above sea level.
Appendix A A-5 Acronym Description RA Resolution Advisory RAIM Receiver Autonomous Integrity Monitoring RCP Required Communication Performance RD Rapid Decompression RNAV Area Navigation RNP Required Navigation Performance RSP Required Surveillance Performance RVSM Reduced Vertical Separation Minimum SAO Special Area(s) of Operation SAR Search and Rescue SARPs Standards and Recommended Practices (ICAO) SATCOM Satellite Communications SATVOICE Satellite Voice SELCAL Selective Calling System SIGWX Significant Weather SLOP Strategic Lateral Offset Procedure SMS Safety Management System SO2 Sulfur Dioxide SOP Standard Operating Procedure SSR Secondary Surveillance Radar SSV Standard Service Volume SUA Special Use Airspace SUPPS Regional Supplementary Procedures (ICAO Doc 7030) SVGM Satellite Voice Guidance Material SWPC Space Weather Prediction Center TAF Terminal Aerodrome Forecast TAS True Airspeed TCAS Traffic Alert and Collision Avoidance System TIBA Traffic Information Broadcasts by Aircraft TMI Track Message Identifier TSO Technical Standard Order
Appendix A A-6 Acronym Description UTC Coordinated Universal Time VAAC Volcanic Ash Advisory Center VFR Visual Flight Rules VHF Very High Frequency VMC Visual Meteorological Conditions VOR Very High Frequency Omnidirectional Range WAT West Atlantic WebOPSS Web-based Operations Safety System WGS 84 World Geodetic System 1984 A.2 Definitions.
A.2.1 Advisory Airspace. Airspace of defined dimensions, or a designated route, within which air traffic advisory service is available.
A.2.2 Aeronautical Information Manual (AIM). A primary FAA publication whose purpose is to provide the aviation community with basic flight information and ATC procedures for use in the NAS of the United States. The AIM contains items of interest to pilots concerning health and medical facts, factors affecting flight safety, a pilot/controller glossary of terms used in the ATC system, and information on safety and accident and hazard reporting.
A.2.3 Aeronautical Information Publication (AIP) (ICAO). A publication issued by or with the authority of a State and containing aeronautical information of a lasting character essential to air navigation.
A.2.4 Aeronautical Telecommunication Station. An aeronautical station which forms part of a radio telephone network by providing air/ground communications and Flight Information Services (FIS) as an integral part of ATS. Aeronautical telecommunication stations are also known as international Flight Service Stations (FSS), Aeronautical Radio, or Aeradio Stations, depending on the State providing the service.
A.2.5 Airborne Collision Avoidance System (ACAS) (ICAO). An aircraft system based on SSR transponder signals, which operates independently of ground-based equipment to provide advice to the pilot on potential conflicting aircraft that are equipped with SSR transponders.
A.2.6 Air Defense Identification Zone (ADIZ). Airspace over land or water, extending upward from the surface, within which the ready identification, location, and control of aircraft are required in the interest of national security.
Appendix A A-7 A.2.7 Air Traffic Advisory Service (ICAO). A service provided within advisory airspace to ensure separation, insofar as practical, between aircraft that are operating on IFR flight plans.
A.2.8 Air Traffic Management (ATM) (ICAO). The dynamic, integrated management of air traffic and airspace including ATS, airspace management, and air traffic flow management—safely, economically, and efficiently—through the provision of facilities and seamless services in collaboration with all parties and involving airborne and ground-based functions.
A.2.9 Air Traffic Management (ATM) System (ICAO). A system that provides ATM through the collaborative integration of humans, information, technology, facilities, and services, supported by air and ground- and/or space-based communications, navigation, and surveillance.
A.2.10 Air Traffic Service (ATS) (ICAO). A generic term meaning variously FIS, alerting service, air traffic advisory service, ATC service, area control service, or approach control service.
A.2.11 Air Traffic Service (ATS) Surveillance System (ICAO). A generic term meaning variously ADS-B, Primary Surveillance Radar (PSR), SSR, or any comparable ground-based system that enables the identification of aircraft. A comparable ground-based system is one that has been demonstrated, by comparative assessment or other methodology, to have a level of safety and performance equal to or better than monopulse SSR.
A.2.12 Alerting Service (ICAO). A service provided to notify appropriate organizations regarding aircraft in need of SAR aid and to assist such organizations as required.
A.2.13 Area Control Center (ACC) (ICAO). A unit established to provide ATC service to controlled flights in CTAs under its jurisdiction. ACCs are the international equivalent of U.S. ARTCC.
A.2.14 Area of Magnetic Unreliability (AMU). For purposes of authorizations for certificated operators, the FAA designates the boundaries of the AMUs as follows:
A.2.14.1 The Northern AMU is the area within 1,000 NM of the Magnetic North Pole but excludes Alaska and its territorial waters. In addition, Canadian Northern Domestic Airspace (NDA) is part of the Northern AMU.
A.2.14.2 The Southern AMU is the area within 1,000 NM of the Magnetic South Pole.
A.2.14.3 As aircraft move towards the Earth’s Magnetic North or South Pole, the horizontal field strength diminishes, and the ability of the compass to accurately sense Magnetic North is reduced. It is generally recognized that when the horizontal magnetic field strength falls below 6,000 nanotesla, the magnetic compass can no longer be considered reliable.
Appendix A A-8 A.2.15 Area Navigation (RNAV) (ICAO). A method of navigation that permits aircraft operation on any desired flightpath within the coverage of ground- or space-based NAVAIDs or within the limits of the capability of self-contained systems or a combination of these.
A.2.16 Automatic Dependent Surveillance (ADS). A surveillance technique in which aircraft automatically provide, via a data link, data derived from onboard navigation and position fixing systems, including ACID, four-dimensional (4D) position, and additional data as appropriate.
A.2.16.1 Automatic Dependent Surveillance-Broadcast (ADS-B) (ICAO). A surveillance system by which aircraft, aerodrome vehicles, and other objects can automatically transmit and/or receive data, such as identification, position, and additional data, as appropriate, in a broadcast mode via a data link.
A.2.16.2 Automatic Dependent Surveillance-Contract (ADS-C) (ICAO). A means by which the terms of an ADS-C agreement will be exchanged between the ground system and the aircraft, via a data link, specifying under what conditions ADS-C reports would be initiated and what data would be contained in the reports. The abbreviated term “ADS contract” is commonly used to refer to ADS event contract, ADS demand contract, ADS periodic contract, or an emergency mode.
A.2.17 Conditional Clearances. A conditional clearance is an ATC clearance given to an aircraft with certain conditions or restrictions, such as changing an FL based on UTC or a specific geographic position. In oceanic and remote continental airspace, this usually involves a restriction to comply with the clearance “BY” or “AT” a certain geographic position or time.
A.2.18 Control Area (CTA) (ICAO). A controlled airspace extending upwards from a specified limit above the Earth.
A.2.19 Controller-Pilot Data Link Communications (CPDLC). A two-way digital communications system that conveys textual ATC messages between controllers and pilots using ground- or satellite-based radio relay stations.
A.2.20 Cross-Checking. Cross-checking is the act of verification. Cross-checking involves matching a set of test data against a set of master data to detect deviations in sequence or content.
A.2.21 Current Flight Plan (ICAO). The flight plan, including changes, if any, brought about by subsequent clearances.
Note: In this AC, we use the term “currently effective route clearance” to refer to the route of flight information in what ICAO Annex 2, Rules of the Air, calls the “current flight plan.”
A.2.22 Dead Reckoning. The navigation of an airplane solely by means of computations based on airspeed, course, heading, wind direction, groundspeed, and elapsed time.
Appendix A A-9 A.2.23 Electronic Flight Bag (EFB). An EFB is any device, or combination of devices, actively displaying EFB applications. EFB applications are categorized as Type A or B and can be hosted on either portable or installed components. A list of EFB applications can be found in the appendices of AC 120-76, Authorization for Use of Electronic Flight Bags.
A.2.24 Erosion of Longitudinal Separation. A loss of required horizontal separation between aircraft operating at the same altitude, on the same oceanic routing, usually due to improper speed control or failure to provide updated voice position reports to ATC in a timely manner on any changes in ETAs in excess of 2 minutes.
A.2.25 Extended Diversion Time Operations (EDTO) (ICAO). Any operation by an airplane with two or more turbine engines where the diversion time to an en route alternate aerodrome is greater than the threshold time established by the State of the Operator.
A.2.26 Extended Operations (ETOPS). An airplane flight operation, other than an all-cargo operation in an airplane with more than two engines, during which a portion of the flight is conducted beyond a time threshold identified in 14 CFR part 121 or 135, that is determined using an approved one-engine-inoperative cruise speed under standard atmospheric conditions in still air.
A.2.27 Fatigue Risk Management System (FRMS) (ICAO). FRMS is a data-driven means of continuously monitoring and managing fatigue-related safety risks, based upon scientific principles and knowledge as well as operational experience that aims to ensure relevant personnel are performing at adequate levels of alertness.
A.2.28 Flight Information Region (FIR) (ICAO). An airspace of defined dimensions within which FIS and alerting services are provided.
A.2.29 Flight Information Services (FIS) (ICAO). A service provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights.
A.2.30 Flight Level (FL) (ICAO). A surface of constant atmospheric pressure which is related to a specific pressure datum (i.e., Standard Pressure—29.92 inHg or 1013.2 hPa) and is separated from other such surfaces by specific pressure intervals.
A.2.31 Flight Operations Officer/Flight Dispatcher (ICAO). A person designated by the operator to engage in the control and supervision of flight operations, whether licensed or not, suitably qualified in accordance with ICAO Annex 1, Personnel Licensing, who supports, briefs, and/or assists the PIC in the safe conduct of the flight.
A.2.32 General Aviation (GA). That portion of civil aviation that does not include scheduled or unscheduled air carriers or commercial space operations.
A.2.33 Global Navigation Satellite System (GNSS) (ICAO). A worldwide position and time determination system that includes one or more satellite constellations, aircraft receivers, and system integrity monitoring, augmented as necessary to support the RNP for the intended operation.
Appendix A A-10 A.2.34 Global Positioning System (GPS). GPS refers to the worldwide positioning, navigation, and timing determination capability available from the U.S. satellite constellation. The service provided by GPS for civil use is defined in the GPS Standard Positioning Service (SPS) Performance Standard. GPS is composed of space, control, and user elements.
A.2.35 Gross Navigation Error (GNE). A GNE is a lateral deviation of 10 NM or more from the aircraft’s cleared route.
A.2.36 High Frequency (HF) Communications. Radio frequencies between 3 and 30 MHz used for air/ground voice communications in overseas operations. HF communications (or, if supported, SATVOICE) capability is required for all IFR operations in controlled airspace when out of the range of VHF communications. If you are in doubt as to the VHF coverage along your intended route of flight, your aircraft should be equipped with HF communications (or SATVOICE, if supported).
A.2.37 High Seas. The seas beyond the 12 NM from the baseline of a shore. Airspace over the high seas is considered international airspace.
A.2.38 Instrument Meteorological Conditions (IMC) (ICAO). Meteorological conditions expressed in terms of visibility, distance from clouds, and ceiling, less than the minima specified for visual meteorological conditions (VMC).
A.2.39 International Civil Aviation Organization (ICAO). ICAO is a specialized agency of the United Nations whose objective is to develop the principles and techniques of international air navigation and to foster planning and development of international civil air transport.
A.2.40 Journey Logbook (ICAO). A record of the flight operation, which should be retained in order to maintain a continuous record of the last 6 months’ operations.
A.2.41 Large Height Deviations (LHD). A deviation from your cleared altitude by 300 feet or more.
A.2.42 Lateral Navigation (LNAV). A function of RNAV equipment that calculates, displays, and provides lateral guidance to a profile or path.
A.2.43 Long-Range Navigation System (LRNS). An electronic navigation unit that is approved for use under IFR as a primary means of navigation. An LRNS must have at least one source of navigational input suitable for oceanic and remote continental navigation, such as an INS or a GPS receiver.
A.2.44 Mach Number Technique. Describes a control technique used by ATC whereby turbojet aircraft operating successively along suitable routes are cleared to maintain appropriate Mach numbers for a relevant portion of the en route phase of flight. The principal objective is to achieve improved utilization of the airspace and to ensure that separation between successive aircraft does not decrease below the established minima.