B737-800
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Total 19800
Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; General Maintenance Action
Aircraft; Procedure
During takeoff noticed [a] strong 'dirty sock' smell. Donned oxygen masks. Confirmed with flight attendants that smell was present throughout cabin. Advised ATC and returned to ZZZ. After blocking in; ZZZ Maintenance told us; that they had done an engine wash the previous night. We were the first departure afterwards. Re-examine the engine wash procedure. This was my second odor and fumes event after an engine wash. Both ended in priority returns to the departure airport. The pack burn after an engine wash is apparently done at 70% power. Takeoff power is much higher!
Departing ZZZ; Captain noticed an acrid odor and verified with First Officer and cabin crew. Advised with ATC and returned to ZZZ. Maintenance confirmed an engine wash was completed overnight prior to this first launch of the day. Odor in cabin. Review maintenance procedures for pack burn after engine wash.
B737-800 flight crew and Flight Attendant reported a 'dirty socks; musty' odor during takeoff and executed an air return.