Appendix A A-13 A.2.59 Procedural Separation (ICAO). The separation used when providing procedural control.
A.2.60 Reduced Vertical Separation Minima (RVSM). RVSMs are 1,000 feet vertical separation between FL 290 and FL 410 inclusive. Operators and aircraft must be authorized by the Administrator to operate in RVSM airspace. An operator may be authorized without application to the FAA when meeting the standards of 14 CFR part 91 appendix G, section 9. Alternatively, the B046 authorization is available as a specific approval, when needed for international operations. For additional guidance, refer to AC 91-85, Authorization of Aircraft and Operators for Flight in Reduced Vertical Separation Minimum (RVSM) Airspace.
A.2.61 Remote Continental Airspace. Airspace over land where VHF voice communications, ATC surveillance (via radar or ADS-B), and reliable ground-based NAVAIDs are not available. ATC is provided using procedural control and procedural separation, with LRCS.
A.2.62 Required Communication Performance (RCP) Specification (ICAO). A set of requirements for ATS provision, aircraft capability, and operations needed to support PBC within a defined airspace.
A.2.63 Required Navigation Performance (RNP) Specification (ICAO). A NavSpec based on RNAV that includes the requirement for performance monitoring and alerting, designated by the prefix RNP (e.g., RNP 2, RNP 4, or RNP APCH).
A.2.64 Required Surveillance Performance (RSP) Specification (ICAO). A set of ATS provisions, including communication services and aircraft and operator requirements, needed for surveillance, supporting a performance-based operation within a defined airspace.
A.2.65 Special Use Airspace (SUA). Consists of airspace of defined dimensions where activities must be confined because of their nature, or where limitations are imposed upon aircraft operations that are not a part of those activities, or both.
A.2.65.1 Prohibited Areas. A prohibited area is an SUA designated under 14 CFR part 73, within which no person may operate an aircraft without the permission of the using agency.
A.2.65.2 Restricted Areas. A restricted area is an SUA designated under 14 CFR part 73, within which the flight of aircraft, while not wholly prohibited, is subject to restriction.
A.2.65.3 Warning Areas. A warning area is airspace of defined dimensions, extending from 3 NM outward from the coast of the United States, which contains activity that may be hazardous to nonparticipating aircraft. The purpose of such a warning area is to warn nonparticipating pilots of the potential danger.
A warning area may be located over domestic or international waters or both.
Appendix A A-14 A.2.66 Target Level of Safety (TLS) (ICAO). A generic term representing the level of risk that is considered acceptable in particular circumstances.
A.2.67 Very High Frequency (VHF). The frequency band between 30 and 300 MHz. Portions of this band, 108–118 MHz, are used for certain NAVAIDs, while 118–136 MHz are used for civil air/ground voice communications.
A.2.68 Visual Meteorological Conditions (VMC). Meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling, equal to or better than specified minima.
A.2.69 Waypoint. A predetermined geographical position that is defined in terms of latitude/longitude coordinates. Waypoints may be a simple named point in space or associated with existing NAVAIDs, intersections, or fixes. A waypoint is most often used to indicate a change in direction, speed, or altitude along the desired path. For purposes of RNAV procedures, waypoints are identified as either:
A.2.69.1 Flyby Waypoint. Flyby waypoints are used when an aircraft should begin a turn to the next course prior to reaching the waypoint separating the two route segments. This is known as turn anticipation.
A.2.69.2 Flyover Waypoint. Flyover waypoints are used when the aircraft must fly over the point prior to starting a turn.
Appendix B B-1 APPENDIX B. OPERATIONAL AUTHORIZATIONS: 14 CFR PART 91 LOAs B.1 Authorization for Oceanic and Remote Continental Operations for 14 CFR Part 91.
The FAA requires all operators to obtain the B036 operational authorization to indicate oceanic Required Navigation Performance (RNP) on air traffic control (ATC) flight plans.
Note: Details on oceanic and remote continental authorizations for certificated operators are available from the responsible Flight Standards office.
B.1.1 Oceanic Authorizations. The 14 CFR part 91 Letter of Authorization (LOA) B036 is called “Oceanic Required Navigation Performance (RNP) Operations.” To indicate an oceanic RNP capability (i.e., RNP 2 (oceanic/remote), RNP 4, or RNP 10) on an ATC flight plan, a B036 is required.
B.1.1.1 The FAA recommends 14 CFR part 91 operators obtain LOA B036 for all oceanic operations. While LOA B036 is not required for 14 CFR part 91 to fly in oceanic airspace, it is required to indicate oceanic RNP capability
(i.e., RNP 2 (oceanic/remote), RNP 4, or RNP 10) on ATC flight plans.
Without RNP capability, you may not be cleared on optimal routes and/or altitudes.
B.1.1.2 For some oceanic areas, 14 CFR part 91 operators require LOA B036. Some oceanic areas require a minimum of RNP 10 capability, including, for example, NAT HLA and Central East Pacific (CEP) routes at FL 290 through FL 410. Certain North Pacific (NOPAC) routes require a minimum of RNP 4 capability (as well as RCP 240 and RSP 180) at certain altitudes. You should consult the AIP of the airspace you are planning to fly in to determine if a specific RNP capability is required. For details on required data communications authorizations associated with RCP 240 and RSP 180, refer to AC 90-117, Data Link Communications.
B.1.2 Remote Continental Authorizations. An optional 14 CFR part 91 LOA B030 is available as a means of documenting FAA endorsement of remote continental training and procedures. That LOA is called “IFR Remote Continental Operations and/or IFR Alaska Special Minimum En Route Altitude (MEA) Operations.”
B.1.3 Long-Range Navigation System (LRNS). Generally, at least two LRNSs are required in oceanic airspace. Operators are encouraged to obtain a B036 for any operations in oceanic flight information regions (FIR). For 14 CFR part 91 subpart F, overwater operations using a single LRNS are permitted, in accordance with 14 CFR § 91.511.
B.1.4 Authorization Process. The FAA uses a five-phase process to approve operator applications. The responsible Flight Standards office can provide you with the details pertinent to each phase and your specific requirements.
B.1.4.1 Phase 1. You determine a need for authorization and contact the FAA.
Appendix B B-2 B.1.4.2 Phase 2. You formally submit a proposal for FAA evaluation.
B.1.4.3 Phase 3. We evaluate the request and determine what level of demonstration is required. We may conduct the demonstration within the responsible Flight Standards office, at your site of operations, or at another suitable location.
B.1.4.4 Phase 4. We observe and evaluate a demonstration of your ability to perform in accordance with your proposal. This is an operational evaluation. If the demonstration is unsuccessful, we will provide feedback on deficient areas and their resolution.
Note: Flight or line observations are not required for General Aviation (GA) LOA applications. For GA operators, we evaluate your application and, if warranted, conduct a knowledge validation (tabletop exercise and/or static airplane demonstration).
B.1.4.5 Phase 5. If your demonstration is successful, we issue the requested operational authorizations.
B.1.5 Operations Safety System (OPSS).26 26 SAS has assumed functions that, before 2025, were performed by OAPS and the Web-based Operations Safety System (WebOPSS).
B.1.5.1 OPSS Access. OPSS is the FAA’s document management system for issuing operational authorizations to air operators as indicated in 14 CFR. Authorized aviation industry personnel can apply for access to OPSS through the Safety Assurance System (SAS) External Portal at https://sas.faa.gov/sas.external.por tal/ext/accounts. OPSS access allows industry personnel to view and propose changes to their authorizations, which can expedite applications.
B.1.5.2 OPSS Training. You will require training prior to receiving OPSS access.
You can accomplish the training either through an FAA inspector or by taking the OPSS formal training course through the FAA’s Mike Monroney Aeronautical Center (MMAC).
Note: The Operations Approval Portal System (OAPS), also accessed via SAS, streamlines processing of authorizations requiring review by the FAA’s Flight Technologies and Procedures Division. OAPS allows bundling and is integrated with OPSS.
B.1.6 Title 14 CFR Part 91 Authorizations. Title 14 CFR part 91 operators can obtain oceanic and/or remote operational authorizations per Table B-1, Title 14 CFR Part 91 LOAs for Oceanic and/or Remote Areas, below:
Appendix B B-3 Table B-1. Title 14 CFR Part 91 LOAs for Oceanic and/or Remote Areas LOA Title Remarks A056 Data Link Communications Required to conduct data link communications in oceanic areas.
B030 IFR Remote Continental Operations and/or IFR Alaska Special Minimum En Route Altitude (MEA) Operations Not required to conduct such operations but is available to document FAA recognition of an operator’s remote continental training and procedures.
B036 Oceanic Required Navigation Performance (RNP) Operations Required to indicate oceanic and remote continental RNP capability. See the discussions in paragraph 2.5.1 and in B.1.1.
B039 Operations in North Atlantic High Level Airspace (NAT HLA) Required to operate in NAT HLA.
B046 Operations in Reduced Vertical Separation Minimum (RVSM) Airspace Required to operate outside FAA-controlled RVSM airspace.
D098 Short-Term Operations in Airspace Requiring Specific Approval Available to authorize operations in oceanic/remote airspace, RVSM airspace, and in NAT HLA.
Appendix B B-4 B.2 Map, Authorization for Optional Single LRNS. Figure B-1 shows the area defined in 14 CFR § 91.511(f), where use of a single LRNS is authorized for 14 CFR part 91 subpart F operators.
Figure B-1. Single Long-Range Navigation System (LRNS) Area
Appendix C C-1 APPENDIX C. UNUSUAL WEATHER ACTIVITY C.1 Volcanic Ash.
C.1.1 In 2010, a small volcano in Iceland erupted, spewing volcanic ash into the atmosphere.
Eyjafjallajokull’s eruption stranded 8 million travelers and resulted in the largest airspace shutdown since World War II. As a result, in 2012, ICAO produced the first edition of ICAO Doc 9974, Flight Safety and Volcanic Ash, which provides guidance for aircraft operators when volcanic ash contamination may be a hazard for flight operations.
Whenever your flight planned route approaches the vicinity of a volcanic ash cloud, you should understand the potentially catastrophic effects ingesting volcanic ash could have on your aircraft engines. Currently, nine Volcanic Ash Advisory Centers (VAAC) offer worldwide coverage of volcanic activity and provide valuable information to assist your trip planning efforts. For more information on the VAACs, go to https://www.ospo.noaa.
gov/Products/atmosphere/vaac/other-vaacs.html.
Figure C-1. ICAO Volcanic Ash Advisory Centers C.1.2 Volcanic eruptions emit various gases along with magma, including sulfur dioxide (SO2) and hydrogen sulfide (H2S). When SO2 gas combines with water in the atmosphere, a sulfate aerosol primarily composed of dilute sulfuric acid is formed. Flying through sulfuric acid aerosols has caused crazing of acrylic windows, fading of exterior paint, and
Appendix C C-2 accumulation of sulfate deposits in engines. SO2 gas is colorless, but under certain conditions of reflection and refraction of sunlight, a sulfuric acid aerosol may be a visible atmospheric feature, such as a layer of haze of variable color (brownish, yellowish, bluish, or whitish). Ash particles likely will be present in aerosol haze but possibly in minor or trace amounts.
C.1.3 Volcanoes are the only sources of large quantities of sulfur gases at cruise altitudes, and both types of sulfur gas have a noticeable smell. SO2 is identifiable as the sharp, acrid odor of a freshly struck match. H2S, also known as sewer gas, has the odor of rotten eggs.
“Electrical smoke and fire” and SO2 are two odors described as somewhat similar. Sulfur gases may be detectable only for a short period of time because of “olfactory fatigue” (temporary loss of the ability to smell a particular odor). Inhalation of SO2, even at low concentrations (<5 parts per million (ppm)), can cause respiratory tract irritation, especially in people with asthma and chronic obstructive pulmonary disease.
C.1.4 If you smell sulfur gases in the cockpit, this may indicate volcanic activity that has not yet been detected or reported and/or your possible entry into an ash-bearing cloud. After determining there are no secondary indications that would result from and indicate an electrical fire, you should establish whether the sulfur odor is transient or not.
C.1.5 You can best achieve this by donning your oxygen mask(s) and breathing 100 percent oxygen for the period of time that results in a complete change of air within the cockpit and also allows you to regain your sense of smell. After the appropriate time period, remove your oxygen mask(s) and determine if the odor is still present. If you confirm the continued presence of sulfur gas, you should inform the controlling Air Traffic Service (ATS) unit and dispatch center as soon as practicable to request information about any relevant volcanic activity and the whereabouts of possible volcanic clouds. You do not have the means to determine directly whether or not the cloud is hazardous; therefore, you should seek to exit the cloud.
C.1.6 You might see other indications of volcanic ash, such as fine dust in the aircraft, St. Elmo’s fire visible around your windshield, and/or a visible glow in the intake of your engines. Your airspeed indications may also become unreliable as the ash contaminates your pitot/static system. The Aeronautical Information Manual (AIM), Chapter 7, Safety of Flight, recommends, in the event of encountering an ash cloud, that pilots reverse course and reduce thrust (altitude permitting) to escape from the cloud, and to disengage autothrottles (as applicable), turn on continuous ignition, and turn on all bleed-powered systems so as to provide additional engine stall margin. In addition, the AIM discusses Pilot Weather Reports (PIREP) related to volcanic ash activity and recommends you complete the Volcanic Activity Reporting Form (VAR), found in appendix 2 of the AIM.
You should avoid flying in the vicinity of known volcanic ash. Attempting to overfly an ash plume is also potentially perilous, as an emergency descent could place the aircraft into the plume.
C.1.7 In 2025, ICAO published ICAO Doc 10157, Procedures for Air Navigation Services— Meteorology, which established a standard format for the Volcano Observatory Notice for Aviation (VONA). The United States Geological Survey (USGS) discusses delivery
Appendix C C-3 of VONAs at https://www.usgs.gov/programs/VHP/volcano-notifications-deliversituational-information.
C.2 Space Weather.
C.2.1 The effects of space weather on aviation have generated an increasing amount of interest in recent years. Space weather most commonly impacts radio communications between your aircraft and ground stations. Space weather may also impact navigation signals from space-based and ground-based transmitters as well as onboard avionics components.
Exposure to increased radiation levels during solar events has not been a noticeable issue, but it is a factor that you can plan for in order to protect your frequently flying crewmembers and passengers.
C.2.2 The magnetic field around the Earth converges at the North and South Poles, allowing charged particles to access lower levels of the Earth’s atmosphere. These lower levels are the same levels used to fly international flights around the world. The aviation community has shown increasing interest in this phenomenon at the poles as the expansion of polar routes has seen more and more flights susceptible to space weather.
C.2.3 The solar cycle is an approximately 11-year period that is characterized by solar activity that departs from the sun and has impacts on whatever celestial bodies are in the path of this space weather. The three effects of this weather are known as radio blackouts, geomagnetic storms, and solar radiation storms. These storms can have varying degrees of short- and long-term impact on ground-based navigation signals, aircraft and aircrew in flight, space-based transmitters, spacecraft, and space crew. The Space Weather Prediction Center (SWPC) tracks these storms and issues space weather watches, warnings, and alerts to inform the public of potential impacts.
Figure C-2. Example of a National Oceanic and Atmospheric Administration Scales Activity Report C.2.4 Space weather alerts can be subscribed to through the SWPC Product Subscription Service and the following link: https://pss.swpc.noaa.gov/ProductSubscriptionService/Lo ginWebForm.aspx.
Appendix C C-4 C.3 Space Weather Advisory Information. Amendment 78 to ICAO Annex 3, Meteorological Service for International Air Navigation (November 2018), introduced a requirement to issue space weather advisory information when necessitated by space weather events. The space weather advisory message is similar in structure to advisory messages for tropical cyclones and volcanic ash clouds issued by the Tropical Cyclone Advisory Centers (TCAC) and VAACs concerned.
C.3.1 Space Weather Advisory Centers issue space weather advisory information when there are impacts to high frequency (HF) communications, communications via satellite, Global Navigation Satellite System (GNSS)-based navigation and surveillance systems, or when heightened radiation occurs.
C.3.2 The advisory message informs the user of:
• The type of impact;
• The expected onset, or that the event is already in progress;
• The duration of the event;
• A generalized description of the spatial extent affected for the next 24 hours; and
• A description of the severity of the impact in moderate (MOD) or severe (SEV) categories.
C.3.3 ICAO Annex 3; ICAO Doc 10100, Manual on Space Weather Information in Support of International Air Navigation; and ICAO NAT Doc 006 – Part III, Space Weather Contingency Procedures, published in 2023, are additional references.
Appendix D D-1 APPENDIX D. SAMPLE OCEANIC CHECKLIST D.1 Sample Abbreviated Oceanic Checklist. This sample abbreviated checklist is provided for your reference. If you do not have an oceanic checklist, we encourage you to use this sample and tailor it to your specific needs and approvals. This checklist focuses on an orderly flow and ways to reduce oceanic errors. You should also review the expanded checklist at paragraph D.2. An oceanic checklist should be published in your international operations manual and evaluated and kept up to date as part of your Safety Management System (SMS), as applicable. The ICAO North Atlantic (NAT) oceanic checklists, which served as the foundation for our checklists, are available in Attachment 4 of NAT Doc 007, posted on the ICAO European and North Atlantic (EUR/NAT) region website, found at https://www.icao.int/EURNAT/EUR-NAT-DOCS?fid=3403.
NAT Doc 007 also discusses oceanic procedures.
D.1.1 Flight Planning.
1. Communications, navigation, and surveillance flight plan codes and planning documents.
2. Oceanic documents.
3. Plotting/orientation chart—plot route coast out to coast in.
4. Equal Time Points (ETP)—plot.
5. Track message (current copy available for all crossings).
6. Note nearest tracks on plotting/orientation chart.
7. Weather analysis—note en route wind, temperature, and turbulence forecasts as well as ETP airport weather.
8. Review suitable Navigational Aids (NAVAID) for accuracy check (as applicable) prior to coast out.
D.1.2 Preflight.
1. Master clock for all estimated times of arrival (ETA)/actual times of arrival (ATA).
2. Maintenance log—check for any communications, navigation, and surveillance or Reduced Vertical Separation Minimum (RVSM) issues.
3. RVSM.
4. Altimeter checks (tolerance).
5. Wind shear or turbulence forecast.
6. Flight plan (check routing, fuel load, times, groundspeeds).
7. Dual long-range navigation system (LRNS) for extended overwater operations outside the range of ground-based NAVAIDs.
8. Voice long-range communication system (LRCS) check (as applicable):
Appendix D D-2
a. High frequency (HF) radio check.
b. Satellite Voice (SATVOICE) operability check.
9. Confirm present position coordinates (best source).
10. Master Document symbols (, , \, X).
11. LRNS programming:
a. Check navigation database currency and software version.
b. Independently verify navigation system/flight management system (FMS) programming.
c. Check expanded coordinates of oceanic waypoints.
d. Check leg course and distance (±2 degrees and ±2 nautical miles (NM)).
e. Upload winds, if applicable.
12. Groundspeed check (as applicable).
D.1.3 Taxi and Prior to Takeoff.
1. Groundspeed check (as applicable).
2. Present position check.
D.1.4 Climb Out.
1. Transition altitude—set altimeters to 29.92 inches of mercury (inHg) (1013.2 hectopascals (hPa)).
2. Calculate/update ETAs on Master Document as duties permit.
D.1.5 Prior to Oceanic Entry.
1. Navigation accuracy check (if required by flight manual)—record results on Master Document.
2. Voice LRCS (HF selective calling system (SELCAL) or SATVOICE Callback) check with aeronautical radio station.
3. Confirm satellite communications (SATCOM) data link is operational, if equipped.
4. Log on to Controller-Pilot Data Link Communications (CPDLC) and Automatic Dependent Surveillance-Contract (ADS-C) 10 to 25 minutes prior, if equipped, unless otherwise specified in the relevant Aeronautical Information Publication (AIP).
5. Verify your Required Navigation Performance (RNP) value is set (as applicable).
6. Confirm flight level (FL), Mach, and route for crossing and verify/cross-check loading of route clearance into the navigation system.
7. Revised clearance—update navigation system, Master Document, and plotting/orientation chart.