A B737-300 on descent declared an emergency due to loss of 'a' system hydraulic pressure and quantit...

Attributes
ACN	553746
Time
Date	200207
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ord.airport
State Reference	IL
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau.artcc
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	arrival star : pmm
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	553746
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 : 'a' pressure and qty indicators other flight crewa other flight crewb
Resolutory Action	flight crew : declared emergency flight crew : overcame equipment problem
Consequence	other other
Supplementary
Problem Areas	Flight Crew Human Performance Maintenance Human Performance Aircraft
Primary Problem	Aircraft

Narrative:

About 80 mi east of ord on the pmm arrival, we lost our system 'a' hydraulic quantity. We ran the checklist for the problem and declared an emergency with ATC. We were cleared direct to ord. The checklist for our problem was to include a manual gear extension. I called the flight attendant and told him what the problem was and then directed him to do a cabin advisory with the other flight attendants and that we should be on the ground in about 15 mins. The manual gear extension went as it should. I told the first officer to make an announcement to the passenger that there would be emergency vehicles along the runway for our landing and that it would be considered normal under the circumstances. The landing was normal and we taxied to the gate under our own power. Callback conversation with reporter revealed the following information: the reporter stated on parking on the gate a technician advised the cockpit not to start the APU as the area was covered with hydraulic fluid. The reporter said the cause of the loss of fluid was a leak in or on the rudder power unit. The reporter stated in checking later in the aircraft history it was found the rudder power unit was replaced.

Original NASA ASRS Text

Title: A B737-300 ON DSCNT DECLARED AN EMER DUE TO LOSS OF 'A' SYS HYD PRESSURE AND QUANTITY CAUSED BY A LEAK ON OR NEAR THE RUDDER PWR UNIT.

Narrative: ABOUT 80 MI E OF ORD ON THE PMM ARR, WE LOST OUR SYS 'A' HYD QUANTITY. WE RAN THE CHKLIST FOR THE PROB AND DECLARED AN EMER WITH ATC. WE WERE CLRED DIRECT TO ORD. THE CHKLIST FOR OUR PROB WAS TO INCLUDE A MANUAL GEAR EXTENSION. I CALLED THE FLT ATTENDANT AND TOLD HIM WHAT THE PROB WAS AND THEN DIRECTED HIM TO DO A CABIN ADVISORY WITH THE OTHER FLT ATTENDANTS AND THAT WE SHOULD BE ON THE GND IN ABOUT 15 MINS. THE MANUAL GEAR EXTENSION WENT AS IT SHOULD. I TOLD THE FO TO MAKE AN ANNOUNCEMENT TO THE PAX THAT THERE WOULD BE EMER VEHICLES ALONG THE RWY FOR OUR LNDG AND THAT IT WOULD BE CONSIDERED NORMAL UNDER THE CIRCUMSTANCES. THE LNDG WAS NORMAL AND WE TAXIED TO THE GATE UNDER OUR OWN PWR. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED ON PARKING ON THE GATE A TECHNICIAN ADVISED THE COCKPIT NOT TO START THE APU AS THE AREA WAS COVERED WITH HYD FLUID. THE RPTR SAID THE CAUSE OF THE LOSS OF FLUID WAS A LEAK IN OR ON THE RUDDER PWR UNIT. THE RPTR STATED IN CHKING LATER IN THE ACFT HISTORY IT WAS FOUND THE RUDDER PWR UNIT WAS REPLACED.

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 B737-300 on descent declared an emergency due to loss of 'a' system hydraulic pressure and quantity caused by a leak on or near the rudder power unit.