Off-duty pilot saves the day during Southwest flight emergency.

An off-duty pilot flying as a passenger helped take control of a Southwest jet after the captain was “incapacitated” by a medical emergency. The Boeing 737 was turned around, landing back in Vegas just before 8 a.m. A backup crew then boarded and took passengers to Columbus as planned, the airline said. The incident is being investigated by the Federal Aviation Administration (FAA) — which hours later issued separate alerts to airlines, pilots and others about the “need for continued vigilance and attention to mitigation of safety risks” after a series of high-profile near collisions.