There are long range radar sites scattered throughout the interior of the United States that the Federal Aviation Administration (FAA) uses to track all aircraft activity between airport terminals. These are known as Primary Surveillance Radar (PSR) because they need nothing from the aircraft for their detection. They simply “paint” the sky with high power RF signals and wait for a bounce back signal. As technology improved a secondary radar system (SSR) was installed at each of these sites. SSR requires communications with an aircraft in that it “asks” the aircraft who are you, where are you, what is your elevation and other pieces of information. This requires the aircraft to have a radio transponder to communicate. However, if you simply turn off the aircraft radio transponder the aircraft is no longer detected in air space. This is what the terrorists did when hijacking the airliners they flew into buildings on September 11, 2001.
These PSR’s date back to the late 1950’s, were past their intended lifetime use, and were costly to maintain. Prior to 9/11 the FAA’s thinking was to decommission all PSR systems and let the SSR systems do all the work for aircraft detection. After the 9/11 attacks, the Department of Transportation and Department of Homeland Security deemed it necessary to upgrade the old PSR systems. The FAA quickly realized that gutting and extensively reworking the old cabinets as they came in from the field was not efficient and would impact the required production schedule. It was deemed beneficial if a pool of brand new specialized cabinets could be readily available upon start of production. The original drawings were long since unobtainable, so draftsmen at the FAA Logistics Center in Oklahoma City used an old unit and generated a preliminary drawing set from scratch. A competitive bid went out and VMA was awarded the contract to manufacture the cabinets.
The drawings provided were only about 80-90% complete. An actual original unit from the 1950's was provided, and through our experience, reverse engineering, and diligence to detail, the documentation was finalized. Many manufacturing suggestions were made & implemented, and production soon began.
These cabinets (and systems) will be deployed to over 68 radar sites across the United States and they will sit there for the next twenty-five years protecting the delicate receiver electronics inside. Ultimately these radar systems will continue to help protect the National Airspace System and the freedoms we Americans enjoy.