What about the radar blip? A ghost image. Is that a common occurence?
Lots of weird stuff is common with all sorts of radar.
Nothing to see here---move along. Those damned air conditioners.
Did they talk about why the Logan air control tapes were taken by the CIA instead of the NTSB?
I don't know which specific radar you are talking about. The way primary (skin track, as opposed to transponder or secondary) ATC radar work, they get lots of "false alarms", at different detection levels.
The standard is generally one false "contact" or "primative" per scan of 360 degrees. ( Navy uses "contact", FAA "primative".) If a primative correlates with another primative on the next scan, a tentative track is formed. After several scans, depending on the design and history of correlated returns, the tenative track is promoted to "established" and reported to ATC or deemed false and dropped.
An uncorrelated plot is insignificant. Several would be significant, even if uncorrelated. Generally, the logic used for ATC will not correlate skin tracks from targets moving with a ground speed in excess of 600 kts, which excludes high performance military jets, and significantly, most air to air missiles.
Ghost images are not nearly so common as they once where. A combination of automatic detection and improved signal processing. However you do get false detections, but those will not be correlated from scan to scan, they will essentially be random "sparkle" (Which is what the AWACS guys call the similar false detections on their radar displays).