Narrative:

The fmh ASR-8 went rapidly out of alignment. Two aircraft were observed on the mapped final approach course for the ILS/RNAV runway 24 at mvy. The following aircraft was cleared for the approach and given an intercept heading that would have had the aircraft intercept the final approach course approximately 4 miles outside of the FAF; at the same time a fourth aircraft was also turned to intercept the final approximately 6 miles in trail. When the first aircraft was 1-2 miles from the FAF I noticed that it appeared about 1/2 mile northwest of course; the pilot was informed and the pilot stated they were established on the final. The aircraft was instructed to contact tower. Seconds later the fourth aircraft was also observed northwest of the final; this time off by about a mile. The aircraft was informed and the pilot responded that their instruments read established on the final. At this time the controller in charge was informed of the anomaly. A scope alignment check was performed; the radar was out of alignment. The fourth aircraft was instructed to contact tower; the other VFR aircraft in the airspace were informed that the radar was out of service and radar contact lost. Meanwhile a coordinator relayed the outage to towers; neighboring facilities; and were informed landing assured on the IFR arrivals into mvy. Recommendation; it seems as though the fmh ASR-8 radar has been riddled with problems on a regular basis. Frequent radar anomalies (false targets/dropped tags/loss of secondary returns at high altitudes) also occur; but a sudden loss of usable radar is a primary concern. It seems that on a near monthly basis I am working a shift in which the fmh radar becomes suddenly unusable. The ack ASR-9 does not seem to be affected by any of these problems; and works as expected. I recommend decommissioning of the fmh ASR-8 as soon as a reliable replacement system is installed. There are serious safety concerns with continued use of a radar system that has many known maintenance issues.

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Original NASA ASRS Text

Title: K90 Controller described a RADAR alignment problem experienced with the FMH ASR-8 RADAR system; suggesting a reliable replacement system be commissioned as soon as possible.

Narrative: The FMH ASR-8 went rapidly out of alignment. Two aircraft were observed on the mapped final approach course for the ILS/RNAV Runway 24 at MVY. The following aircraft was cleared for the approach and given an intercept heading that would have had the aircraft intercept the final approach course approximately 4 miles outside of the FAF; at the same time a fourth aircraft was also turned to intercept the final approximately 6 miles in trail. When the first aircraft was 1-2 miles from the FAF I noticed that it appeared about 1/2 mile NW of course; the pilot was informed and the pilot stated they were established on the final. The aircraft was instructed to contact tower. Seconds later the fourth aircraft was also observed NW of the final; this time off by about a mile. The aircraft was informed and the pilot responded that their instruments read established on the final. At this time the CIC was informed of the anomaly. A scope alignment check was performed; the RADAR was out of alignment. The fourth aircraft was instructed to contact tower; the other VFR aircraft in the airspace were informed that the RADAR was out of service and RADAR contact lost. Meanwhile a coordinator relayed the outage to towers; neighboring facilities; and were informed landing assured on the IFR arrivals into MVY. Recommendation; it seems as though the FMH ASR-8 RADAR has been riddled with problems on a regular basis. Frequent RADAR anomalies (false targets/dropped tags/loss of secondary returns at high altitudes) also occur; but a sudden loss of usable RADAR is a primary concern. It seems that on a near monthly basis I am working a shift in which the FMH radar becomes suddenly unusable. The ACK ASR-9 does not seem to be affected by any of these problems; and works as expected. I recommend decommissioning of the FMH ASR-8 as soon as a reliable replacement system is installed. There are serious safety concerns with continued use of a RADAR system that has many known maintenance issues.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.