A B737-300 in cruise at FL330 declared an emergency and diverted due to loss of left hydraulic system pressure and quantity. Cause unknown.

Home

Browse by month

Random

Latest

About

Contact

Attributes
ACN	499393
Time
Date	200101
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : phx.airport
State Reference	AZ
Altitude	msl single value : 33000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zab.artcc
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Route In Use	enroute airway : j18.airway
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : multi engine pilot : atp pilot : cfi pilot : commercial
Experience	flight time last 90 days : 200 flight time total : 20000 flight time type : 8000
ASRS Report	499393
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : left hyd press and qty ind other flight crewa other flight crewb
Resolutory Action	flight crew : declared emergency flight crew : diverted to another airport
Consequence	other
Supplementary
Problem Areas	Environmental Factor Flight Crew Human Performance Aircraft
Primary Problem	Aircraft

Narrative:

Soon after leveloff at FL330, first officer noticed 'a' hydraulic quantity was about 1/2 full and appeared to be dropping. We quickly reviewed volume ii hydraulic system information, verified gauge accuracy and contacted ZZZ maintenance control. As we were discussing this problem with them, we ran out of radio range, so we contacted phx dispatch/maintenance control over abq radio. By this time, fluid level had dropped to approximately 3/8 of a tank, so maintenance agreed that the best course of action was to return to phx. Level continued to drop to 1/4 and 'a' hydraulic engine driven pump low pressure light illuminated. Shutoff pump per QRH and it appeared fluid level was stabilized. We extended landing gear with 'a' system on downwind. By the time we were on base leg, system pressure read normal. However, hydraulic quantity was on empty. Landed on runway 7L with flaps 40 degrees and were able to taxi in and park with normal 'a' hydraulic pressure. Maintenance technician came up to cockpit and said we had a mess of hydraulic fluid in left wheel well and on the left main gear.

Original NASA ASRS Text

Title: A B737-300 IN CRUISE AT FL330 DECLARED AN EMER AND DIVERTED DUE TO LOSS OF L HYD SYS PRESSURE AND QUANTITY. CAUSE UNKNOWN.

Narrative: SOON AFTER LEVELOFF AT FL330, FO NOTICED 'A' HYD QUANTITY WAS ABOUT 1/2 FULL AND APPEARED TO BE DROPPING. WE QUICKLY REVIEWED VOLUME II HYD SYS INFO, VERIFIED GAUGE ACCURACY AND CONTACTED ZZZ MAINT CTL. AS WE WERE DISCUSSING THIS PROB WITH THEM, WE RAN OUT OF RADIO RANGE, SO WE CONTACTED PHX DISPATCH/MAINT CTL OVER ABQ RADIO. BY THIS TIME, FLUID LEVEL HAD DROPPED TO APPROX 3/8 OF A TANK, SO MAINT AGREED THAT THE BEST COURSE OF ACTION WAS TO RETURN TO PHX. LEVEL CONTINUED TO DROP TO 1/4 AND 'A' HYD ENG DRIVEN PUMP LOW PRESSURE LIGHT ILLUMINATED. SHUTOFF PUMP PER QRH AND IT APPEARED FLUID LEVEL WAS STABILIZED. WE EXTENDED LNDG GEAR WITH 'A' SYS ON DOWNWIND. BY THE TIME WE WERE ON BASE LEG, SYS PRESSURE READ NORMAL. HOWEVER, HYD QUANTITY WAS ON EMPTY. LANDED ON RWY 7L WITH FLAPS 40 DEGS AND WERE ABLE TO TAXI IN AND PARK WITH NORMAL 'A' HYD PRESSURE. MAINT TECHNICIAN CAME UP TO COCKPIT AND SAID WE HAD A MESS OF HYD FLUID IN L WHEEL WELL AND ON THE L MAIN GEAR.

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.