Using Hawk-Eye on clay would require more technological adjustments than it would on hard courts, according to the company's director of tennis.
According to Peter Irwin, Hawk-Eye officials would have to spend 30 minutes re-configuring their setup after each match.
"One thing that’s integral to our system is we measure the court, but we also measure the undulations in the ground,” Irwin told *The New York Times*. “So when you play on clay, obviously the ground is constantly changing, so that would require a lot more work from our side. We would constantly have to recalibrate the system if it were to be used for officiating.
“On a hard court, we do it once at the start of the tournament because the surface doesn’t change. On grass, we do calibrate constantly throughout, but clay is just a lot more."
However, he added that swirling clay, rainfall and minor accumulations on court do not affect Hawk-Eye accuracy.
A questioned call on clay is decided by an umpire looking at the mark. French Open officials have no plans to add electronic line calling.
"On clay, it’s easy—there is the mark," Jeremy Botton, the chief executive, told the newspaper.
He added that the human element also sets the surface apart from the others.
"I don't see why we'd change it," he said.
No official tour events on clay use electronic line calls.