|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1801 To 2400|
|Locale Reference||atc facility : ord|
|Altitude||msl bound lower : 14000|
msl bound upper : 14000
|Operator||common carrier : air carrier|
|Make Model Name||ATR 42|
|Flight Phase||cruise other|
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Qualification||pilot : commercial|
pilot : cfi
|Experience||flight time last 90 days : 210|
flight time total : 2700
flight time type : 650
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Anomaly||aircraft equipment problem : critical|
other anomaly other
|Independent Detector||aircraft equipment other aircraft equipment : unspecified|
other flight crewa
|Resolutory Action||flight crew : declared emergency|
While at altitude en route from ord to lacrosse, wi, a cockpit panel light illuminated indicating hydraulic fluid 'low level.' the PNF (the captain) ran through the appropriate abnormal checklist which, among other things, required the shutoff of one of our hydraulic pumps. The checklist stated that as a result we would lose the ability to normally extend the landing gear and that we would lose all normal braking. The PNF informed company of our problem while PF (myself) turned the aircraft around back to ord and informed ATC of our problem. We were cleared by radar vectors to ord, had to execute an emergency gear extension procedure (gravity gear extension), landed on runway 27L, slowed using reverse thrust only, and finally came to a stop with the emergency/parking brake on one of the 'high speed' txwys. Since we could not taxi without brakes, passenger and bags were unloaded by our company out on the taxiway. There were no passenger or crew injuries and no damage to aircraft except leaking hydraulic fluid from the belly of the aircraft. Callback conversation with reporter revealed the following information: the reporter stated the exact cause of the hydraulic fluid loss is unknown as maintenance only advised the crew a line or a fitting on the line failed. The reporter said the segment of line and fitting leaking were in the green system located in the wheel well.
Original NASA ASRS Text
Title: AN ATR42 IN CRUISE AT 14000 FT DECLARED AN EMER AND DIVERTED DUE TO LOSS OF THE GREEN HYD SYS PRESSURE AND QUANTITY CAUSED BY A FAILED FITTING OR LINE.
Narrative: WHILE AT ALT ENRTE FROM ORD TO LACROSSE, WI, A COCKPIT PANEL LIGHT ILLUMINATED INDICATING HYD FLUID 'LOW LEVEL.' THE PNF (THE CAPT) RAN THROUGH THE APPROPRIATE ABNORMAL CHKLIST WHICH, AMONG OTHER THINGS, REQUIRED THE SHUTOFF OF ONE OF OUR HYD PUMPS. THE CHKLIST STATED THAT AS A RESULT WE WOULD LOSE THE ABILITY TO NORMALLY EXTEND THE LNDG GEAR AND THAT WE WOULD LOSE ALL NORMAL BRAKING. THE PNF INFORMED COMPANY OF OUR PROB WHILE PF (MYSELF) TURNED THE ACFT AROUND BACK TO ORD AND INFORMED ATC OF OUR PROB. WE WERE CLRED BY RADAR VECTORS TO ORD, HAD TO EXECUTE AN EMER GEAR EXTENSION PROC (GRAVITY GEAR EXTENSION), LANDED ON RWY 27L, SLOWED USING REVERSE THRUST ONLY, AND FINALLY CAME TO A STOP WITH THE EMER/PARKING BRAKE ON ONE OF THE 'HIGH SPD' TXWYS. SINCE WE COULD NOT TAXI WITHOUT BRAKES, PAX AND BAGS WERE UNLOADED BY OUR COMPANY OUT ON THE TXWY. THERE WERE NO PAX OR CREW INJURIES AND NO DAMAGE TO ACFT EXCEPT LEAKING HYD FLUID FROM THE BELLY OF THE ACFT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE EXACT CAUSE OF THE HYD FLUID LOSS IS UNKNOWN AS MAINT ONLY ADVISED THE CREW A LINE OR A FITTING ON THE LINE FAILED. THE RPTR SAID THE SEGMENT OF LINE AND FITTING LEAKING WERE IN THE GREEN SYS LOCATED IN THE WHEEL WELL.
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.