An MD88 in cruise at FL330 declared an emergency and diverted due to loss of right main hydraulic sy...

Attributes
ACN	532566
Time
Date	200111
Day	Sat
Local Time Of Day	1801 To 2400
Place
State Reference	LA
Altitude	msl single value : 33000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zfw.artcc
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 150 flight time total : 9885 flight time type : 3006
ASRS Report	532566
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : right hydraulic quantity indicator other flight crewa other flight crewb
Resolutory Action	flight crew : diverted to another airport flight crew : declared emergency
Consequence	other other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Shortly after level off, noticed right hydraulic system qty at 1 quart, with normal press. Depressurized right system in accordance with pom. Procedure has system repressurized prior to configuring for landing. When system repressurized, pressure was normal but qty 1. When flaps/slats extended, pressure and qty both dropped to zero. Pressure rtned to normal and qty rtned to 1 quart when flap/slat movement was complete. When gear handle lowered, qty and pressure again fell to zero. Both main gear showed down and locked, but nose gear indicated unsafe and gear doors indicated open. After approximately 90 seconds, the situation did not change. Performed alternate gear extension in accordance with pom. After gear indicated safe, pressure recovered. Accomplished normal landing. Maintenance met aircraft on runway to pin gear and stow doors. Subsequent taxi in was normal. Callback conversation with reporter revealed the following information: the reporter stated the cause of the hydraulic failure was not reported by maintenance even though a request was sent with the log report.

Original NASA ASRS Text

Title: AN MD88 IN CRUISE AT FL330 DECLARED AN EMER AND DIVERTED DUE TO LOSS OF RIGHT MAIN HYD SYS QTY AND PRESSURE. CAUSE UNKNOWN.

Narrative: SHORTLY AFTER LEVEL OFF, NOTICED RIGHT HYDRAULIC SYS QTY AT 1 QUART, WITH NORMAL PRESS. DEPRESSURIZED RIGHT SYS IAW POM. PROCEDURE HAS SYS REPRESSURIZED PRIOR TO CONFIGURING FOR LNDG. WHEN SYS REPRESSURIZED, PRESSURE WAS NORMAL BUT QTY 1. WHEN FLAPS/SLATS EXTENDED, PRESSURE AND QTY BOTH DROPPED TO ZERO. PRESSURE RTNED TO NORMAL AND QTY RTNED TO 1 QUART WHEN FLAP/SLAT MOVEMENT WAS COMPLETE. WHEN GEAR HANDLE LOWERED, QTY AND PRESSURE AGAIN FELL TO ZERO. BOTH MAIN GEAR SHOWED DOWN AND LOCKED, BUT NOSE GEAR INDICATED UNSAFE AND GEAR DOORS INDICATED OPEN. AFTER APPROX 90 SECS, THE SIT DID NOT CHANGE. PERFORMED ALTERNATE GEAR EXTENSION IAW POM. AFTER GEAR INDICATED SAFE, PRESSURE RECOVERED. ACCOMPLISHED NORMAL LNDG. MAINT MET ACFT ON RWY TO PIN GEAR AND STOW DOORS. SUBSEQUENT TAXI IN WAS NORMAL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE CAUSE OF THE HYD FAILURE WAS NOT RPTED BY MAINT EVEN THOUGH A REQUEST WAS SENT WITH THE LOG RPT.

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.

An MD88 in cruise at FL330 declared an emergency and diverted due to loss of right main hydraulic system qty and pressure. Cause unknown.