NOTAM, AIRAC and Briefing Products

The AIP records the lasting world; this lesson covers everything that changes faster than a publication cycle. It opens with the NOTAM (when one must be issued, when one must not, and how the network distributes it) and its two special series for snow and volcanoes. Then the AIRAC system, which disciplines the world's significant changes onto common dates; the aeronautical information circular for everything that fits nowhere else; the briefing products that put it all in front of a crew before flight and collect their observations after it; and the European regulation that binds the service providers.

When a NOTAM is born

The trigger rule first: a NOTAM is originated and issued promptly whenever the information to be distributed is of a temporary nature and of short duration, or when operationally significant permanent changes, or temporary changes of long duration, are made at short notice. One carve-out matters enough to be its own learning objective: information that would in principle belong in a NOTAM but contains extensive text and/or graphics is published as an AIP Supplement instead; the NOTAM format is telegraphic, and a ten-page procedure change would break it.

What must be notified reads like an inventory of everything a crew relies on. The essentials, compressed from the Annex's own list:

Aerodromes, runways and services — establishment, closure or significant changes of aerodromes or runways; establishment, withdrawal or significant changes of aeronautical services; changes to and limitations on the availability of fuel, oil and oxygen; major changes to search and rescue; significant changes in the rescue and fire fighting protection level — but only when the CATEGORY changes.
Aids and lighting — establishment, withdrawal or significant operational-capability changes of radio navigation and air-ground communication services, including interruptions and returns to service, frequency and identification changes, and power changes of 50 per cent or more; changes to visual aids; interruption or return to operation of major components of aerodrome lighting; hazard beacons marking obstacles.
Procedures, hazards and airspace — establishment, withdrawal or significant changes of air navigation procedures; major defects in the manoeuvring area; regulations requiring immediate action; hazards affecting air navigation, including obstacles, military exercises, displays, races and major parachuting outside promulgated sites; obstacle changes in the take-off, climb, missed approach, approach areas and runway strip; changes in the status of prohibited, restricted or danger areas; interception-possibility areas where guard on 121.5 MHz is required; location indicator changes.
Contamination and the exotic — hazardous conditions due to snow, slush, ice, radioactive material, toxic chemicals, volcanic ash or water on the movement area; epidemics changing inoculation and quarantine requirements; operationally significant volcanic activity, eruptions and ash clouds with the levels and routes affected; radioactive or toxic releases after nuclear or chemical incidents; the emergence of conflict zones; planned laser emissions, displays and searchlights that could impair night vision; humanitarian relief missions; and short-term ATS contingency measures. (One veteran of this list has retired: forecasts of solar cosmic radiation, once a NOTAM trigger, now travel as space weather advisories under the meteorological Annex.)

Equally examinable is what shall not be notified by NOTAM:

routine maintenance on aprons and taxiways that does not affect safe movement;
runway marking work when other runways are usable or the equipment can be moved off;
temporary obstructions near the aerodrome that do not affect safe operations;
partial lighting failures that do not directly affect operations;
partial, temporary communication failures with suitable alternative frequencies working;
missing apron marshalling and road traffic control;
unserviceable location and destination signs, and similar trivia.

Three refinements complete the picture: at least seven days' advance notice is given of the activation of established danger, restricted or prohibited areas and of temporary restrictions (emergencies excepted); an unserviceability NOTAM estimates the period of unserviceability or the expected time of restoration; and every AIRAC AIP Amendment or Supplement is announced by a trigger NOTAM — a brief description, effective date and reference, coming into force on the amendment's own effective date and staying in the pre-flight information bulletin for fourteen days.

The special series: SNOWTAM and ASHTAM

Two hazards earned their own formats:

SNOWTAM — a special series in its own standard format, disseminating information on snow, slush, ice, frost and standing water on the movement area. Today the format carries the surface condition report of the global reporting format, runway by runway, and a SNOWTAM is valid for a maximum of eight hours, replaced whenever a new runway condition report arrives.
ASHTAM — a special series notifying, in its specific format, a change in the activity of a volcano, a volcanic eruption and/or a volcanic ash cloud of operational significance, carrying the volcano's name and position, its alert-level colour code, the location, extent and movement of the ash cloud, and the flight levels and routes or portions of routes affected.

How NOTAM travel

Distribution has its own tested clauses. NOTAM are distributed on the basis of a request: a State pushes nothing to a user who has not asked for the series. The pipe is the aeronautical fixed service (AFS), employed whenever practicable, each NOTAM transmitted as a single telecommunication message and composed from the ICAO NOTAM Code, abbreviations and plain language, brief enough that its meaning is clear without reference to another document. Each NOTAM belongs to a series identified by a letter, with a consecutive four-digit number based on the calendar year. Internationally, the originating State selects which NOTAM receive international distribution, and the exchange takes place between international NOTAM offices, as mutually agreed, with selective distribution lists recommended to spare recipients what does not concern them. And the bookkeeping is itself a NOTAM: a checklist of valid NOTAM is issued as a NOTAM checklist at intervals of not more than one month, one per series, referring to the latest amendments, supplements, the internationally distributed AIC — and, in the data-centric regime, the current data sets.

AIRAC: the world changes on schedule

A navigation database that learns about a moved waypoint late is worse than one that never learns at all, so the significant changes of the aeronautical world are disciplined onto a calendar. Under AIRAC, the listed circumstances are distributed on a series of common effective dates at intervals of 28 days, and the information notified must then remain unchanged for at least another 28 days after the effective date, unless it was temporary and lapses earlier. The information shall travel by AIRAC when it establishes, withdraws or significantly changes:

Airspace and routes — the limits, regulations and procedures of flight information regions, control areas, control zones, advisory areas and ATS routes; permanent danger, prohibited and restricted areas and ADIZ; and permanent interception-possibility areas.
Aids and facilities — positions, frequencies, call signs and identifiers of radio navigation aids and of communication and surveillance facilities; meteorological facilities and procedures.
Procedures and levels — holding and approach procedures, arrival and departure procedures, noise abatement and other pertinent ATS procedures; transition levels, transition altitudes and minimum sector altitudes; aerodrome operating minima where a State publishes them.
The aerodrome itself — runways and stopways, taxiways and aprons, ground operating procedures including low-visibility procedures, and approach and runway lighting.

The AIC

The aeronautical information circular is the residual channel: originated whenever information must be promulgated that qualifies neither for the AIP nor for a NOTAM, and whenever it is desirable to publish:

a long-term forecast of major changes in legislation, regulations, procedures or facilities;

purely explanatory or advisory information liable to affect flight safety;

explanatory and advisory notifications on technical, legislative or administrative matters.

The Annex's own examples run from forecasts of new navigation systems, safety lessons from accident investigations and medical advice for pilots, to licensing arrangements, noise abatement explanations, selected airworthiness directives, new chart editions — and the seasonal update of the snow plan, issued at least one month before the normal onset of winter conditions.

Its organisation: each AIC carries a consecutive serial number based on the calendar year; when circulated in more than one series, each series is identified by a letter; colour coding by subject is recommended once the circulars in force are numerous enough to need it; a checklist of AIC currently in force is issued at least once a year; and an AIC selected for international distribution gets the same distribution as the AIP.

Before the flight, and after it

At any aerodrome normally used for international operations, the information essential to the route stages originating there is made available to flight operations personnel. For pre-flight planning that means the relevant elements of the integrated package, plus maps and charts, and, the tested list, additional current information about the aerodrome of departure:

construction or maintenance work on or next to the manoeuvring area;

rough portions of the manoeuvring area, marked or not;

the presence and depth of snow, ice or water on runways and taxiways, with the effect on friction;

snow drifted or piled beside the runways and taxiways;

parked aircraft or other objects on or next to taxiways;

other temporary hazards;

birds constituting a potential hazard;

failures of any part of the aerodrome lighting system, including the power supply;

failures or status changes of the surveillance, data link, navigation and RVR systems and the secondary power supply;

any humanitarian relief missions operating.

The recap product the syllabus names: a recapitulation of valid NOTAM of operational significance, and other information of urgent character, is made available to flight crews as plain-language pre-flight information bulletins (PIB), increasingly through automated self-briefing systems, which must keep their databases continuously updated and give crews telephone or telecommunications access to the AIS when the machine is not enough. And the flow runs backwards after landing: aerodromes make arrangements to receive from aircrews information on the state and operation of air navigation facilities or services, and on the presence of wildlife hazards, birds above all, and pass it to the AIS for such distribution as the circumstances necessitate — the crew who found the glide path bent are the system's last sensor.

The European layer

One EU instrument closes the module: Commission Implementing Regulation (EU) 2017/373, the common requirements for service providers in air traffic management. The syllabus wants its scope stated, and the scope is the answer: 2017/373 provides general requirements for the provision of air navigation services, and specific requirements for the provision of air traffic services, of meteorological services, of aeronautical information services, and of communication, navigation or surveillance services — with further specific requirements reaching beyond those four, from data services and flow management to flight procedure design and the Network Manager.