Reading and Applying NOTAMs at Dispatch: Format and Priorities

A Notice to Air Missions (NOTAM) is a time-critical advisory that tells the aviation community about conditions that were not known far enough in advance to be published in standard aeronautical charts or procedures. For the aircraft dispatcher, NOTAMs are not optional reading — they are a legal and operational obligation that must be evaluated before every dispatch release. Missing a relevant NOTAM can expose a flight to a closed runway, an inoperative navaid, a temporary flight restriction, or a hazard that makes the originally planned route or alternate unsuitable.

This article breaks down the NOTAM system as the FAA has structured it, explains how to decode the format, and gives practical guidance on how dispatchers establish priorities when dozens of NOTAMs apply to a single flight.

The NOTAM System: Background and Authority

The FAA's NOTAM system is governed by the Aeronautical Information Manual (AIM), Chapter 5, and coordinated through the FAA Air Traffic Organization's Traffic Flow Management (TFM) infrastructure. The Federal NOTAM System (FNS) replaced the legacy NOTAM-D/NOTAM-L/NOTAM-FDC taxonomy, though the underlying content categories remain familiar. All NOTAMs are now distributed through the FAA NOTAM Search tool and through airline operational control systems that pull from the same centralized database.

Under 14 CFR Part 121, a dispatcher shares legal responsibility with the pilot in command for the safety of each flight. That responsibility includes reviewing all applicable NOTAMs before issuing a dispatch release. A dispatcher who issues a release without checking NOTAMs — or who fails to communicate a safety-critical NOTAM to the flight crew — has failed a fundamental duty.

NOTAM Format: Decoding the Structure

Every NOTAM follows a standardized structure. Understanding each field makes it possible to scan hundreds of NOTAMs quickly and flag the ones that demand action.

• Q-code field (Qualification line): A coded line containing the FIR identifier and a two-letter subject/condition code (e.g., QRLCA), used for automated sorting and filtering of NOTAM traffic. It is not the same as the accountability/location identifier for the affected facility.
• NOTAM Number: A sequential identifier, e.g., 1/2345, allowing tracking and cross-referencing.
• Series Letter: Identifies the originating facility's series (e.g., A for FAA NOTAM Center).
• Effective Time (B/C fields): The begin date-time group and estimated end date-time group in UTC (Zulu). A NOTAM with PERM in the end field means the condition has been made permanent and incorporated into charts or publications.
• Keyword: A critical field that categorizes the subject — RWY (runway), TWY (taxiway), APRON, AD (aerodrome), NAVAID, COM (communications), SVC (service), AIRSPACE, OBST (obstacle), or others. Dispatchers use the keyword to sort quickly.
• Location Identifier: The ICAO or FAA identifier for the affected facility or airspace, e.g., KORD for Chicago O'Hare.
• Free-text Body: Describes the actual condition in abbreviated ICAO and FAA standard language. Abbreviations such as U/S (unserviceable), AUTH (authorized), CLSD (closed), BTN (between), and AGL/MSL are universal across NOTAMs.

A dispatcher reading KORD RWY 10L/28R CLSD 2405010600-2405011400 knows immediately: Runway 10L/28R at O'Hare is closed from 0600Z to 1400Z on May 1, 2024. That has direct impact on any flight releasing during that window that might use or need that runway for departure, landing, or as an alternate runway option.

NOTAM Categories That Matter Most to Dispatchers

Airspace NOTAMs (TFRs and Special-Use Airspace)

Temporary Flight Restrictions (TFRs) issued under 14 CFR 91.137, 91.138, 91.141, and 91.143 restrict or prohibit flight in a defined volume of airspace. TFRs appear as AIRSPACE keyword NOTAMs and can be issued for disaster areas, VIP movements, space operations, and stadium events. A dispatcher must check the lateral and vertical boundaries as well as the time window, because a TFR that activates two hours after departure could be active during cruise or descent. TFRs are also published in graphic form through the FAA TFM system and on the FAA TFR map, which dispatchers should cross-check.

Aerodrome and Runway NOTAMs

Closed runways directly affect takeoff performance calculations, alternate suitability, and minimum fuel planning. If a departure airport's primary runway is closed and the only available runway is shorter, the dispatcher must re-run takeoff performance. If a destination airport's runway is closed and the remaining runways do not support the planned approach category, an alternate may be required even if one was not initially necessary. Similarly, a closed or unserviceable instrument landing system (ILS) at an alternate can disqualify that airport unless the dispatcher recalculates alternate minimums using the remaining approaches.

NAVAID NOTAMs

An unserviceable VOR, ILS, or GPS augmentation service (such as a WAAS outage) can render an approach unavailable. Dispatchers must verify that every planned instrument approach — at the destination and at the alternate — has a functioning navaid supporting it. An ILS out of service means the crew must use a higher-ceiling approach; if weather is at or below the published minimums for the backup approach, the dispatcher cannot legally release to that destination without a suitable alternate.

FDC NOTAMs (Regulatory Amendments)

Flight Data Center NOTAMs amend charted instrument procedures and other regulatory publications. Common FDC NOTAMs raise approach minimums due to an obstacle survey, change a procedure's course, or place a hold-short line at a new location. These are among the most safety-critical NOTAMs a dispatcher encounters because they change what a published chart says. A crew flying an approach with old minimums, unaware that an FDC NOTAM raised the decision altitude by 200 feet, could inadvertently descend below a safe altitude. Dispatchers must check FDC NOTAMs for every destination and alternate instrument approach in the release.

Traffic Management Unit (TMU) and ATCSCC NOTAMs

The FAA Air Traffic Control System Command Center (ATCSCC, now branded as the Air Traffic Control System Command Center) issues Ground Delay Programs (GDPs), Ground Stops (GS), and Airspace Flow Programs (AFPs) that directly restrict departure times and routing. These initiatives are coordinated through the FAA TFM system and communicated to dispatchers via NOTAMs, the FAA Command Center website, and airline collaborative decision-making (CDM) tools. A GDP NOTAM will specify the affected airport, the program start and end time, the arrival rate, and the population of flights controlled. The dispatcher must calculate the controlled departure time (CDT) assigned to each flight, build delay into the fuel plan, and determine whether the delay makes a different routing or altitude more efficient.

Establishing Priorities: A Practical Hierarchy

Dispatchers routinely face 50 to 150 NOTAMs for a single long-haul operation. A workable priority hierarchy prevents critical items from being buried in low-significance entries.

1. TFRs and airspace closures — affect route legality. Must be resolved before release.
2. Destination runway and navaid status — affects whether the flight can land legally given forecast weather.
3. FDC NOTAMs for destination and alternate approaches — affects minimum safe altitudes.
4. Alternate airport runway and navaid status — affects alternate legality under 14 CFR 121.617.
5. GDP/Ground Stop NOTAMs — affects departure timing and fuel planning.
6. En route navaid and airway NOTAMs — affects route validity and contingency diversion options.
7. Departure airport NOTAMs — affects takeoff performance and taxi routing.
8. Low-priority items — crane lights, non-movement area construction, non-impacting service reductions.

Key Numbers and Rules

• NOTAMs are issued in UTC (Zulu time). Always convert to local time when briefing crews to prevent confusion.
• A NOTAM with PERM as the end time means the information has been or will be incorporated into permanent publications — the NOTAM itself is no longer the primary reference once charted.
• TFRs under 14 CFR 91.137 (disaster/hazard) typically extend from the surface to a stated altitude; 91.138 covers Hawaii volcanic activity; 91.141 covers VIP movements; 91.143 covers space operations.
• FDC NOTAMs that amend approach minimums are regulatory — flying lower than an FDC-raised DA/MDA is a violation regardless of what the chart shows.
• Under 14 CFR 121.601, the dispatcher must provide the pilot in command with all available information useful to the safety of the flight, which courts and the FAA interpret to include relevant NOTAMs.
• GDP-assigned controlled departure times (CDTs) are tracked in real time; dispatchers must monitor for slot swaps, cancellations, and compression events throughout the operation.

Common Test Traps

• Confusing NOTAM time zones: NOTAM times are always UTC. An exam question may give a NOTAM active window and ask whether a flight departing at a given local time is affected — convert carefully.
• Assuming a closed ILS automatically closes the airport: A closed ILS means that approach is unavailable, but other approaches may still be usable. The dispatcher must re-check whether remaining approaches meet alternate or destination minimums given actual weather.
• Overlooking FDC NOTAMs: Candidates often focus on aerodrome NOTAMs and miss FDC entries that raise minimums or change procedures. FDC NOTAMs are legally binding amendments.
• Treating GDP NOTAMs as advisory only: A Ground Stop or GDP is an ATC initiative that must be complied with. Departing before a controlled departure time without coordination is a regulatory violation and an operational safety risk.
• Missing the alternate's NOTAMs: Dispatchers sometimes check the destination thoroughly and neglect the alternate. An alternate with a closed runway or unserviceable ILS may no longer meet the requirements of 14 CFR 121.617, requiring a different alternate or additional fuel.