B757-200 experiences improper xfer of hydraulic fluid from right to left system.

Attributes
ACN	675175
Time
Date	200510
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzzz.airport
State Reference	FO
Altitude	msl single value : 36000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny.artcc
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Route In Use	enroute : atlantic
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : relief pilot
ASRS Report	675175
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : eicas
Resolutory Action	flight crew : landed in emergency condition flight crew : declared emergency
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

EICAS message for right hydraulic system low. Checked right system was indeed low and slowly decreasing. Left system was increasing. Suspected hydraulic fluid xfer. Phone patch to maintenance and dispatch to discuss situation. It was decided to depressurize the right system to save fluid and re-pressurize prior to landing. Emergency was declared; system was re-pressurized prior to landing; landing was normal and uneventful.

Original NASA ASRS Text

Title: B757-200 EXPERIENCES IMPROPER XFER OF HYD FLUID FROM R TO L SYS.

Narrative: EICAS MESSAGE FOR R HYD SYS LOW. CHKED R SYS WAS INDEED LOW AND SLOWLY DECREASING. L SYS WAS INCREASING. SUSPECTED HYD FLUID XFER. PHONE PATCH TO MAINT AND DISPATCH TO DISCUSS SITUATION. IT WAS DECIDED TO DEPRESSURIZE THE R SYS TO SAVE FLUID AND RE-PRESSURIZE PRIOR TO LNDG. EMER WAS DECLARED; SYS WAS RE-PRESSURIZED PRIOR TO LNDG; LNDG WAS NORMAL AND UNEVENTFUL.

Data retrieved from NASA's ASRS site as of January 2009 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.