A B757 has a hydraulic fluid leak resulting in the aircraft diverting.

Attributes
ACN	593284
Time
Date	200309
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : den.airport
State Reference	CO
Altitude	msl single value : 37000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdv.artcc
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	593284
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	aircraft equipment other aircraft equipment : hyd quantity indication
Resolutory Action	flight crew : diverted to another airport flight crew : landed as precaution
Consequence	other other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

During cruise, we noticed the right hydraulic reservoir light was illuminated. When we checked the EICAS status page, the right hydraulic quantity indicated 47% refill and was slowly decreasing. At that time we ran the appropriate checklists and decided to make a precautionary diversion to denver in light of the fact we would be down to 2 hydraulic system. While on approach to ILS runway 16R just outside of sakic, we switched to denver tower and received our landing clearance later we were told by tower to switch back to the approach frequency. When we checked in with approach we were told to slow to our final approach speed and stay with him. He additionally stated he had not previously instructed us to change to tower frequency. After landing, denver maintenance discovered a large leak in an o-ring in the right engine pylon.

Original NASA ASRS Text

Title: A B757 HAS A HYD FLUID LEAK RESULTING IN THE ACFT DIVERTING.

Narrative: DURING CRUISE, WE NOTICED THE R HYD RESERVOIR LIGHT WAS ILLUMINATED. WHEN WE CHKED THE EICAS STATUS PAGE, THE R HYD QUANTITY INDICATED 47% REFILL AND WAS SLOWLY DECREASING. AT THAT TIME WE RAN THE APPROPRIATE CHKLISTS AND DECIDED TO MAKE A PRECAUTIONARY DIVERSION TO DENVER IN LIGHT OF THE FACT WE WOULD BE DOWN TO 2 HYD SYS. WHILE ON APCH TO ILS RWY 16R JUST OUTSIDE OF SAKIC, WE SWITCHED TO DENVER TWR AND RECEIVED OUR LNDG CLRNC LATER WE WERE TOLD BY TWR TO SWITCH BACK TO THE APCH FREQ. WHEN WE CHKED IN WITH APCH WE WERE TOLD TO SLOW TO OUR FINAL APCH SPD AND STAY WITH HIM. HE ADDITIONALLY STATED HE HAD NOT PREVIOUSLY INSTRUCTED US TO CHANGE TO TWR FREQ. AFTER LNDG, DENVER MAINT DISCOVERED A LARGE LEAK IN AN O-RING IN THE R ENG PYLON.

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.