A B767 in cruise at FL310 declared an emergency and diverted due to loss of 'C' system hydraulic pre...

Attributes
ACN	412638
Time
Date	199808
Day	Sun
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : kbv
State Reference	FO
Altitude	msl bound lower : 31000 msl bound upper : 31000
Environment
Light	Night
Aircraft 1
Controlling Facilities	artcc : zny
Operator	common carrier : air carrier
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other other other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	412638
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

At XA50Z en route from jfk to gru, we had a 'C' hydraulic quantity status message. We checked the lower EICAS screen and it indicated .45 'C' hydraulic quantity. We performed the 'C' hydraulic quantity checklist procedure and the 'C' hydraulic system pressure checklist procedure. We contacted ZNY, declared an emergency, requested clearance back to jfk and advised them we would be dumping fuel to get down to maximum landing weight. We advised dispatch of our situation and had the flight attendants perform their emergency landing checklist. At 80 mi out of jfk we performed an altitude flap and gear extension. We made a normal 20 degree flap landing at jfk. After landing, 'C' hydraulic quantity indicated .27. Maintenance inspected the aircraft and found skydrol leaking from the right main landing gear. Maintenance installed gear pins and towed us to the gate. There were no passenger injuries. Callback conversation with reporter revealed the following information: the reporter stated the exact cause of the leak on the right main landing gear is not known by the reporter but it was a component or line on the gear assembly.

Original NASA ASRS Text

Title: A B767 IN CRUISE AT FL310 DECLARED AN EMER AND DIVERTED DUE TO LOSS OF 'C' SYS HYD PRESSURE AND QUANTITY CAUSED BY A FAILED LINE OR COMPONENT ON THE R MAIN LNDG GEAR.

Narrative: AT XA50Z ENRTE FROM JFK TO GRU, WE HAD A 'C' HYD QUANTITY STATUS MESSAGE. WE CHKED THE LOWER EICAS SCREEN AND IT INDICATED .45 'C' HYD QUANTITY. WE PERFORMED THE 'C' HYD QUANTITY CHKLIST PROC AND THE 'C' HYD SYS PRESSURE CHKLIST PROC. WE CONTACTED ZNY, DECLARED AN EMER, REQUESTED CLRNC BACK TO JFK AND ADVISED THEM WE WOULD BE DUMPING FUEL TO GET DOWN TO MAX LNDG WT. WE ADVISED DISPATCH OF OUR SIT AND HAD THE FLT ATTENDANTS PERFORM THEIR EMER LNDG CHKLIST. AT 80 MI OUT OF JFK WE PERFORMED AN ALT FLAP AND GEAR EXTENSION. WE MADE A NORMAL 20 DEG FLAP LNDG AT JFK. AFTER LNDG, 'C' HYD QUANTITY INDICATED .27. MAINT INSPECTED THE ACFT AND FOUND SKYDROL LEAKING FROM THE R MAIN LNDG GEAR. MAINT INSTALLED GEAR PINS AND TOWED US TO THE GATE. THERE WERE NO PAX INJURIES. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE EXACT CAUSE OF THE LEAK ON THE R MAIN LNDG GEAR IS NOT KNOWN BY THE RPTR BUT IT WAS A COMPONENT OR LINE ON THE GEAR ASSEMBLY.

Data retrieved from NASA's ASRS site as of July 2007 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.

A B767 in cruise at FL310 declared an emergency and diverted due to loss of 'C' system hydraulic pressure and quantity caused by a failed line or component on the right main landing gear.