From the Sister Klaryta Antoszewska Photograph Collection (PH-00352). 

Description given with photo: "Hughes Pilots Radar-Equipped Plane Culver City, Calif. -- First passenger plane equipped with radar is flown in demonstration May 1st by Howard Hughes (left) and co-pilot R.C. Loomis over Culver City. Pilots using this equipment will be warned of approaching obstacles by lights flashing on radar panel. Two lights (lefts) with 2,000-foot range, are used to guarantee clearance over mountains; two lights (right) with 500-foot range, are a safety device for approaches and landings. Either set of lights warns against approaching aircraft. Trans-World Airline plans to install radar on its passenger planes. Credit (ACME) 5-3-47."