A Southwest Airlines employee went berserk yesterday, nearly killing his boss with a pipe in a break room at La Guardia Airport, police said.

Calvin Williams, 33, a ramp worker, allegedly used the three-foot pipe to repeatedly smash his supervisor, John Georgiou, 49, on the head, according to law-enforcement sources.

Williams was charged with assault, weapons possession and harassment for the 2:30 p.m. attack, which left Georgiou in critical condition at Elmhurst Hospital.

It was not clear what sparked the incident.