Inoperative / unreliable / off air
Also written: off air, unreliable
An aid or radio service is not working as charted or published.
"INOPERATIVE" and "OFF AIR" say that something is not working: a fog signal, a RACON, a radio station, a DGPS correction service, a coast station's GMDSS watch. "UNRELIABLE" says it may work but should not be relied on — a light showing intermittently, a service subject to interruptions.
These notices affect how a ship navigates and communicates rather than what is in the water, and many run until further notice.
What the archive shows
12,151 messages in this archive use “Inoperative / unreliable / off air”, the earliest issued 1987-03-09 and the latest 2026-09-23. 46 of them are in force in the latest lists we collected. A hazard reported again and again counts once per message.
The largest yearly count is 2017, with 675 messages. Collection is incomplete between 2024-05 and 2026-08-17, so 2024, 2025 and 2026 are not comparable with fully collected years.
Nav aids accounts for 11,422 of 12,151 recorded messages (94%), the largest warning type group in this selection.
Located messages that use it fall in 75 sea areas; the most frequent are North Sea (1,819), North Atlantic Ocean (889) and Inner Seas off the West Coast of Scotland (655).
Its use is spread fairly evenly through the year: the busiest month, October, has 1,112 messages and the quietest, May, 876.
By warning series: HYDROLANT 6,186, HYDROPAC 3,271, NAVAREA IV 1,273 and NAVAREA XII 1,017, and 8 more.
Messages using it, by year of issue
By month of issue, all years
Where it appears · 75 sea areas
In force now · 46
- NOAAORR-11223 · Spills · North Pacific Ocean2026-09-22 · in force
…analysis for 977 gallons of JP-5 (Jet Propellant-5). Additional information is unavailable at this time. 2. THREAT: OIL. 3. POSITION 35.401N 120.973W. NOAA INCIDENTNEWS 11223:…
C22G+FM morro bay, ca, USA → - AUSCOAST 297/26 · Other · Bass Strait2026-09-18 · in force
…AIS NAVIGATION MARKS IN AN AREA BOUNDED BY 38-23S TO 38-37S AND 148-25E TO 148-37E INOPERATIVE
8 virtual AIS navigation marks in an area bounded by 38-23S to 38-37S and 148-25E to 148-37E inoperative → - NAVAREA XI 400/26 · Nav aids · North Pacific Ocean2026-09-07 · in force
NORTH PACIFIC, MARIANAS. GUAM HF NAVTEX STATION, V, 13-29.0N 144-50.0E, OFF AIR.
Guam hf NAVTEX station, V, 13-29.0N 144-50.0E, off air → - HYDROPAC 2450/26 · Nav aids · Coral Sea2026-08-27 · in force
CORAL SEA. AUSTRALIA. RACON AT NORTH REEF LIGHT 23-11.10S 151-54.18E UNRELIABLE.
RACON at north reef light 23-11.10S 151-54.18E unreliable → - AUSCOAST 283/26 · Nav aids · Coral Sea2026-08-26 · in force
NORTH REEF RACON ALRS VOL 2 NUMBER K3014 IN POSITION 23-11.10S 151-54.18E UNRELIABLE
North reef RACON alrs vol 2 number K3014 in position 23-11.10S 151-54.18E unreliable → - HYDROPAC 2438/26 · Nav aids · South Pacific Ocean2026-08-26 · in force
…PACIFIC. CHILE. MAGALLANES RADIO 53-09.92S 070-54.28W MF AND HF DSC RECEIVE SERVICES OFF AIR.
Magallanes radio 53-09.92S 070-54.28W mf and hf dsc receive services off air →
How it reads in recent messages
- NAVAREA XII 654/26 · Nav aids · Gulf of Alaska2026-09-22
…COMMUNICATION FACILITY KODIAK 57-46.00N 152-34.00W HF AND MF TRANSMIT CAPABILITIES UNRELIABLE 1600Z TO 0030Z DAILY 23 THRU 25 SEP. 2. CANCEL NAVAREA XII 259/25. 3. CANCEL THIS MSG…
Uscg remote communication facility kodiak 57-46.00N 152-34.00W hf and mf transmit capabilities unreliable… → - AUSCOAST 298/26 · Nav aids · Arafura Sea2026-09-20
DUYFKEN POINT LIGHT IN POSITION 12-34.15S 141-35.98E UNRELIABLE
Duyfken point light in position 12-34.15S 141-35.98E unreliable → - HYDROLANT 1848/26 · Nav aids · Inner Seas off the West Coast of Scotland2026-09-17
SEA OF THE HEBRIDES. SCOTLAND. 1. DUBH ARTACH LIGHT 56-08.0N 006-38.1W UNRELIABLE. 2. CANCEL HYDROLANT 1847/26.
Dubh artach light 56-08.0N 006-38.1W unreliable → - NAVAREA XII 633/26 · Other · North Pacific Ocean2026-09-16
…USCG REMOTE COMMUNICATION FACILITY HONOLULU 21-22.00N 158-09.00W RECEIVE CAPABILITIES INOPERATIVE.
Uscg remote communication facility honolulu 21-22.00N 158-09.00W receive capabilities inoperative → - NAVAREA IV 894/26 · Nav aids · North Atlantic Ocean2026-09-16
CARIBBEAN SEA. PUERTO RICO. NAVTEX STATION SAN JUAN (R) 18-27.00N 066-06.00W INOPERATIVE.
NAVTEX station san juan (r) 18-27.00N 066-06.00W inoperative → - HYDROPAC 2673/26 · Nav aids · South Pacific Ocean2026-09-16
EASTERN SOUTH PACIFIC. CHILE. VALPARAISO RADIO 33-04.70S 071-36.80W DSC SERVICES OFF AIR.
Valparaiso radio 33-04.70S 071-36.80W dsc services off air →
Earliest in the archive
- NOAAORR-6451 · Spills · North Pacific Ocean1987-03-09
…wind and weather conditions, thus making fuel trajectory forecasts difficult and unreliable. By March 12, the salvage crew, Underwater Construction, reported that the vessel had…
Ulak island, aleutian islands →
Often in the same message
Related terms
- RACON (radar beacon)
- A radar beacon on a buoy, lighthouse or structure that answers a ship's radar with a Morse-code mark on the screen.
- NAVTEX
- An automated medium-frequency radio service that sends coastal warnings as text to a small printer or screen on board.
- Unlit / extinguished
- A light, buoy or structure that is not showing its charted light.
- GNSS / GPS
- Satellite positioning — GPS and other systems — and the testing, jamming and interference that make it unreliable in an area.
Warning types that use it
- Nav aids — Lights extinguished, buoys off station, RACON/NAVTEX outages.
Counts cover the messages in this archive that use the term, recounted 2026-09-24; see coverage for what is collected and since when. Not for navigation — follow official NAVAREA and coastal broadcasts.