Date: 201401
Local time of day: 1201-1800
Location: SBN.Airport, IN
Aircraft: PA-28R Cherokee Arrow All Series
Flight plan: IFR
Flight phase: Cruise
Airspace: Class E SBN
ATC / advisory: TRACON SBN
Reporter organization: Government
Reporter function: Approach; Departure
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Other / Unknown
Anomaly: ATC Issue All Types
Detector: Person Air Traffic Control
Result: General None Reported / Taken
Contributing factors: ATC Equipment / Nav Facility / Buildings; Human Factors; Procedure
Primary problem: ATC Equipment / Nav Facility / Buildings

Narrative: I was working the South Low Sector at SBN Approach. I received a Primary only handoff from Fort Wayne Approach (FWA). I questioned why the aircraft was not on V38 as required in the SBN/FWA LOA and didn't really receive an answer. This V38 requirement is usually let slide by the SBN controllers; but since the aircraft did not have an operating transponder; I didn't understand why FWA amended the flight plan to remove V38. Approximately 6 miles into SBN airspace; I was not receiving a primary return from the aircraft; a P28R. I advised the pilot that our equipment has difficulty sometimes and wanted to make sure everything was going OK. The pilot stated that things were fine and he was still in level flight at 6;000 FT. I asked another Controller to help observe the aircraft and help me track it. The primary return was absolutely gone for approximately 8 miles. I advised pilot of RADAR contact lost at which point I observed a primary target approximately 8 miles away from data block along the course the aircraft had been tracking. I reestablished RADAR contact through identifying turns. During this time my FLM and 2 other controllers observed the absence and reappearing of the primary target. Our tech ops people were advised again that the RADAR was not tracking primary targets continuously; at which point we were advised that there is a known blocked area in the south part of our airspace. Our RADAR's inability to continuously track targets has long been documented and several teams have been brought to SBN to evaluate our RADAR equipment and remedy the problem. Today was the first time any of us in the TRACON have ever heard of any blocked area anywhere in our airspace. I don't know exactly what that means; and don't know how it effects our ability to provide RADAR separation between user's of our airspace. The poor performance of our RADAR has been the topic of past reports and some of us wonder what is being done. It is not safe to continuously lose primary and beacon targets off our scopes when people's lives depend on us using that information to separate aircraft. The obvious fix for most of what I described is to figure out what the issue is with our RADAR and then correct it to ensure it operates dependably. Next; I believe FWA should place the aircraft that are described in the FWA/SBN LOA on the agreed upon routes. They need to stop shortcutting aircraft and putting them on routes that we then have to reroute because they gave them routing that goes into Chicago Approach (C90) airspace.




Synopsis: SBN Controller described an unsafe situation when inbound 'primary only' traffic was not on the prescribed LOA route and the RADAR equipment failed to display any type of target.