When the radar shows a target that AIS does not list, which of the following may be the cause?

When the radar shows a target that AIS does not list, which of the following may be the cause?

• A. The target's AIS transponder may be faulty or switched off
• B. The radar system must be calibrated
• C. The target is too far for radar range
• D. The position report was not updated in AIS

Answer: (A)

When radar detects a target that is not listed on the Automatic Identification System (AIS), one of the primary reasons could indeed be that the target's AIS transponder is faulty or switched off. AIS relies on transponders installed on vessels to broadcast their position and other relevant information. If a vessel's transponder is malfunctioning, not powered, or deliberately turned off (as can occur with some vessels that are not required to operate AIS), it will not appear on an AIS display even though it is still visible to radar. Additionally, while radar and AIS systems can complement each other in terms of target detection, they operate independently. Therefore, the radar may show a target that is completely functioning and operational without it necessarily being reflected in the AIS data. It is crucial for navigators to be aware of this potential disconnect and to exercise caution when radar shows targets absent from AIS, especially in collision avoidance scenarios.

When radar detects a target that is not listed on the Automatic Identification System (AIS), one of the primary reasons could indeed be that the target's AIS transponder is faulty or switched off. AIS relies on transponders installed on vessels to broadcast their position and other relevant information. If a vessel's transponder is malfunctioning, not powered, or deliberately turned off (as can occur with some vessels that are not required to operate AIS), it will not appear on an AIS display even though it is still visible to radar.

Additionally, while radar and AIS systems can complement each other in terms of target detection, they operate independently. Therefore, the radar may show a target that is completely functioning and operational without it necessarily being reflected in the AIS data. It is crucial for navigators to be aware of this potential disconnect and to exercise caution when radar shows targets absent from AIS, especially in collision avoidance scenarios.