United Airlines flight UA688 from Washington DC to Boston declared an emergency and returned to Washington.
Flight UA688 was forced to return to Washington following a technical issue.
The Boeing 737-900ER departed at 17:33 EDT from IAD airport runway 30.
The aircraft (reg. N68801) climbed to 29,000 ft when the crew noticed a mechanical issue with one of the engine.
Pilots contacted ATC requesting a return to the origin airport only 30 minutes after takeoff.
The left engine suffered low oil pressure, it was remained on at idle while flying back.
The 737 landed without incident on runway 1R. It taxied to gate under its own power.
Airport fire provided a quick inspection upon landing.
