How a Q-code is built
The NOTAM Code is defined in ICAO Doc 8400 (PANS-ABC). Every group has five letters, and the first is always Q, chosen so that it cannot be mistaken for a radio call sign. The second and third letters identify the subject; the fourth and fifth letters give its status of operation. The code also standardises the wording of item E), the NOTAM text.
So QMRLC reads as Q + MR (runway) + LC (closed), and QWPLW reads as Q + WP (parachute jumping exercise, paragliding or hang gliding) + LW (will take place).
ICAO Doc 8126 adds the NOTAM Selection Criteria: tables that pair the common codes with the traffic, purpose and scope qualifiers that follow them in the Q-line. That pairing is why a runway closure is listed under the aerodrome in your bulletin and a parachute drop under the navigation warnings. See how to read a NOTAM for the whole Q-line.
Subjects: the second letter
The second letter places the subject in a group. Doc 8400 arranges them as follows:
| Letter | Group | Example subjects (letters 2–3) |
|---|---|---|
| A | ATM: airspace organization | AC control zone (CTR), AT terminal control area (TMA), AR ATS route, AZ aerodrome traffic zone (ATZ) |
| S | ATM: air traffic and VOLMET services | ST aerodrome control tower, SE flight information service, SA ATIS |
| P | ATM: air traffic procedures | PI instrument approach procedure, PD standard instrument departure, PA standard instrument arrival |
| C | CNS: communication and radar facilities | CA air/ground facility, CS secondary surveillance radar |
| I | CNS: instrument and microwave landing systems | IC ILS, IG glide path, IL localizer |
| G | CNS: GNSS services | GA GNSS airfield-specific operations, GW GNSS area-wide operations |
| N | CNS: terminal and en-route navigation facilities | NV VOR, NB NDB, ND DME, NM VOR/DME |
| L | AGA: lighting facilities | LP PAPI, LA approach lighting system, LR all landing area lighting facilities |
| M | AGA: movement and landing area | MR runway, MX taxiway, MN apron |
| F | AGA: facilities and services | FA aerodrome, FU fuel availability, FF fire fighting and rescue |
| R | Navigation warnings: airspace restrictions | RD danger area, RR restricted area, RP prohibited area, RT temporary restricted area, RA airspace reservation |
| W | Navigation warnings: warnings | WP parachute jumping, WM missile, gun or rocket firing, WA air display, WE exercises, WU unmanned aircraft |
| O | Other information | OB obstacle, OL obstacle lights, OA aeronautical information service |
XX as the second and third letters means the subject is not in the code list; item E) describes it in plain language.
Conditions: the fourth letter
The fourth letter groups the status of operation:
| Letter | Group | Common conditions (letters 4–5) |
|---|---|---|
| A | Availability | AS unserviceable, AU not available, AH hours of service are now as given in item E), AP available with prior permission, AK resumed normal operation, AO operational |
| C | Changes | CA activated, CD deactivated, CE erected, CH changed, CS installed, CN cancelled |
| H | Hazard conditions | HW work in progress, HV work completed, HX concentration of birds, HA braking action |
| L | Limitations | LC closed, LT limited to, LW will take place, LV closed to VFR operations, LI closed to IFR operations |
| XX | Other | No listed condition fits; plain language in item E) |
Two endings are special. TT marks a trigger NOTAM that announces an AIRAC AIP amendment or supplement, and KKKK (as in QKKKK) marks a checklist of valid NOTAMs. NOTAMs that cancel an earlier one use endings such as AK (resumed normal operation), AO (operational), CC (completed), CN (cancelled) or HV (work completed).
Q-codes pilots meet most often
These codes turn up regularly in European pre-flight bulletins. The decodes follow ICAO Doc 8400; item E) always gives the detail.
| Code | Decode | What it usually tells you |
|---|---|---|
QMRLC | Runway closed | A runway named in item E) is closed; check whether another runway stays available. |
QMXLC | Taxiway closed | A taxiway, or part of one, is closed; expect a different taxi route. |
QFALC | Aerodrome closed | The aerodrome is closed, often with exceptions listed in item E). |
QFALT | Aerodrome limited | Operations are restricted; item E) says to whom or to what. |
QFAHW | Aerodrome work in progress | Works on the aerodrome; item E) says where and what is affected. |
QFAAH | Aerodrome hours of service are now as given in item E) | Opening hours differ from those published in the AIP. |
QOBCE | Obstacle erected | A new obstacle, often a crane, with position, height and elevation in item E). |
QOLAS | Obstacle lights unserviceable | The lighting of a charted obstacle is out; matters at night and in poor visibility. |
QLPAS | PAPI unserviceable | No visual approach slope guidance on the runway named in item E). |
QICAS | ILS unserviceable | The whole ILS is out of service. |
QNMAS | VOR/DME unserviceable | The navaid is out; procedures and routes that rely on it may be affected. |
QPIAU | Instrument approach procedure not available | The procedure named in item E) cannot be flown. |
QACCA | Control zone activated | A part-time CTR is active, with its clearance and radio rules. |
QRTCA | Temporary restricted area activated | A temporary restricted area is active, for example around an air display or a special event. |
QRRCA | Restricted area activated | A published restricted area is active; entry is restricted to the published conditions. |
QRDCA | Danger area activated | A published danger area is active; activity dangerous to aircraft may take place inside. |
QRACA | Airspace reservation activated | A reserved volume of airspace is active; see TRA and TSA. |
QWMLW | Missile, gun or rocket firing will take place | Firing inside the limits given in items F) and G). |
QWPLW | Parachute jumping exercise will take place | Parachuting, paragliding or hang gliding around the point given. |
QWALW | Air display will take place | An air display; often paired with a temporary restricted area. |
QWELW | Exercises will take place | Military or other exercises inside the limits in items F) and G). |
QWULW | Unmanned aircraft will take place | Unmanned aircraft activity inside the limits in items F) and G). |
The code tells you what kind of notice it is; only item E) tells you which runway, which crane and how high.
Worked example: decoding two codes
Two codes, decoded letter by letter:
QMRLC: M is the movement and landing area group and MR is runway; L is the limitations group and LC is closed. Runway closed. Its Q-line normally carries scope A, so it is listed under the aerodrome in item A) of your bulletin.QWMLW: W is the warnings group and WM is missile, gun or rocket firing; LW is will take place. Firing will take place. It is a navigation warning, so items F) and G) give its vertical limits and the Q-line lower and upper fields restate them as flight levels (with terrain elevation added to any AGL limit).
What the code cannot tell you
The Q-code is a strong first filter, but it has limits:
- The issuing NOTAM office chooses the code. OPADD asks offices to choose the operationally significant one: a parking area closed for works is
QMKLC(closed), notQMKHW(work in progress). Practice still varies between offices. - A NOTAM deals with one subject and one condition. Related changes, such as a navaid outage and the procedures that depend on it, can arrive as separate NOTAMs with different codes.
XXin either half means no listed code fitted. Read item E).- Filtering a bulletin by Q-code alone can hide something important. Narrow by time, area and height first, then by subject.
Before your next flight
Use the code to triage, then read the notice:
- Brief your route or an airport radius so only the relevant NOTAMs remain.
- Check the R and W codes against your altitude and time window; graphical NOTAMs show them on the map.
- Look up any abbreviation in the NOTAM and airspace glossary.