Just outside Slidell, near the eastern end of Lake Pontchartrain, north of New Orleans, a huge radar dish was turning in the night, protected inside its white dome.
It was a civilian radar, used by the FAA to track airliners as they flew from hubs like Houston and New Orleans along the southern US coast, or out over the Gulf of Mexico to the southern Florida cities of Miami and Tampa. But it was also part of the USAF Southern Defense Network, providing air traffic control for the military forces stationed at New Orleans, Houston, Eglin and Tyndall. And, unknown to most Slidell residents, it was also watching and listening for unexpected flights, especially those originating in Cuba.
The spate of recent hijackings in and out of Havana had put the Defense Network on alert multiple times, but it was the undetected arrival of 19 Cubans aboard a Russian-built turboprop directly into New Orleans International in October 1971 that had highlighted the vulnerability of the US underbelly. Consequently, Congress directed the USAF to build better sensing equipment, and as a direct result, standing next to the big white Slidell dome, there was a new FPS-6 height-finder radar, providing more detailed information to Tyndall Air Force Base in Florida, which would scramble jets to intercept unidentified traffic. At Tyndall, NORAD had also built the world’s first large phased array AN/FPS-85 radar, a huge, white, flat structure tipped towards the sky, to watch for southern threats in the atmosphere and all the way up into orbit.
On this November night, the radars were tracking a target that had taken off from Havana with no international flight plan and was now flying westward across the Gulf. The speed and altitude identified it as a probable transport plane, and the Defense Network technician watching on her radar screen had assigned it a tentative marker as an unknown Cuban/Soviet turboprop. It wasn’t typical of air traffic between Cuba and Mexico, and it also wasn’t following any standard route. But it was keeping to international uncontrolled airspace, well south of the US Air Defense Identification Zone, so none of the armed jets that were holding alert at Tyndall or New Orleans had been assigned to investigate.
The technician used one of her radarscope’s features to draw a trace of the flight path thus far, and she laid her finger on the screen to extrapolate where the bogey was likely to fly on that course. Probably one of the northern Mexico airports, maybe Monterrey, or even all the way to Mexicali or Tijuana. That would be a long flight, but her primary concern was that it would get closest to the ADIZ when it was south of Texas. By her finger track, it looked as though it would remain just clear.
Mexico’s Air Traffic Control would have to deal with it, not her, but she was definitely going to watch it as it plodded across the Gulf. There were always headwinds there, and her groundspeed readout showed a meager 340 knots.
Something slightly interesting to keep track of through the night.