A B737-400 captain reported a 'dirty socks' type of smell in the cockpit after extending the landing...

Narrative:

A hydraulic odor; or 'dirty sock' smell was detected in the flight deck and passenger cabin shortly after landing gear was extended. Flight landed uneventfully and taxied to the gate where maintenance was notified. Both flight deck crew members and one cabin crew member smelled the odor. It caused my eyes to burn accompanied by a bitter; metallic taste in my mouth. According to the maintenance technician a hydraulic leak was detected by him in the main landing gear well. Apparently the hydraulic fumes somehow made it into the flight deck and cabin after the landing gear was extended. After landing; air conditioning packs were turned off and flight deck windows were opened for ventilation after slowing to a safe taxi speed. I considered donning my O2 mask but due to our proximity to the ground (less than 1;500 AGL) I didn't want to be distracted from the primary task of safely flying the jet. Maintenance needs to insure that future events like this do not occur. This is my eighth hydraulic exposure at work that I am aware of since november of 2006.

Original NASA ASRS Text

Title: A B737-400 Captain reported a 'dirty socks' type of smell in the cockpit after extending the landing gear. Odor traced to a hydraulic leak in a main landing gear wheel well.

Narrative: A hydraulic odor; or 'dirty sock' smell was detected in the flight deck and passenger cabin shortly after landing gear was extended. Flight landed uneventfully and taxied to the gate where maintenance was notified. Both Flight Deck Crew members and one Cabin Crew member smelled the odor. It caused my eyes to burn accompanied by a bitter; metallic taste in my mouth. According to the Maintenance Technician a hydraulic leak was detected by him in the main landing gear well. Apparently the hydraulic fumes somehow made it into the flight deck and cabin after the landing gear was extended. After landing; air conditioning packs were turned off and flight deck windows were opened for ventilation after slowing to a safe taxi speed. I considered donning my O2 mask but due to our proximity to the ground (less than 1;500 AGL) I didn't want to be distracted from the primary task of safely flying the jet. Maintenance needs to insure that future events like this do not occur. This is my eighth hydraulic exposure at work that I am aware of since November of 2006.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	856355
Time
Date	200910
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Component
Aircraft Component	Hydraulic System
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

A B737-400 captain reported a 'dirty socks' type of smell in the cockpit after extending the landing gear. Odor traced to a hydraulic leak in a main landing gear wheel well.