B757 captain reported 'pungent dirty gym sock smell' on takeoff to 14;000 feet.

Attributes
ACN	1691411
Time
Date	201910
Aircraft 1
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Takeoff
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 130 Flight Crew Total 2184 Flight Crew Type 1936
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

Narrative:

During takeoff with a full thrust setting; we experienced a very pungent dirty gym sock smell on takeoff around 100kts until 14;000 ft. During climb we also entered visible moisture; which most likely exasperated the smell/fumes as well. This is consistent with the guidance currently available for this type of event; which occurs at high power setting on takeoff; or during thrust reduction during a descent. Moisture entering the engines will normally pick up small oil particulates; and they then can pyrolyze entering the ecs (environmental control system) system. This is also prevalent during any event; which can allow small oil particles to become heated to an extreme temperature to form a mist when entering the ecs.

Original NASA ASRS Text

Title: B757 Captain reported 'pungent dirty gym sock smell' on takeoff to 14;000 feet.

Narrative: During takeoff with a full thrust setting; we experienced a very pungent dirty gym sock smell on takeoff around 100kts until 14;000 ft. During climb we also entered visible moisture; which most likely exasperated the smell/fumes as well. This is consistent with the guidance currently available for this type of event; which occurs at high power setting on takeoff; or during thrust reduction during a descent. Moisture entering the engines will normally pick up small oil particulates; and they then can pyrolyze entering the ECS (Environmental Control System) system. This is also prevalent during any event; which can allow small oil particles to become heated to an extreme temperature to form a mist when entering the ECS.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.