US airline regulators have launched an investigation after an engine cowling on a Boeing plane fell off during takeoff and struck the wing flap, the latest in a series of safety problems facing the aircraft manufacturer.
Southwest Airlines flight 3695 rose to about 3,140 metres (10,300ft) before returning safely 25 minutes after takeoff to Denver international airport at about 8.15am local time on Sunday. It was towed to the gate after landing.
The Boeing aircraft with 135 passengers and six crew members onboard had been headed to Houston, Texas. No one was injured.