Narrative:

During cruise at 16000 ft; gear unsafe light illuminated. Followed emergency non-normal procedure for gear-up unsafe condition. Procedure called for the gear to be recycled. When gear was placed in the down position; we could hear the hydraulic pump running but no verbal indication of the gear extending. After about 1 min with no gear down lights illuminated; noticed hydraulic quantity indications decreasing rapidly. With no direction in the gear up unsafe position procedure for this situation; we turned off the hydraulic pump. With the gear up unsafe procedure ending at this point with the gear down; we proceeded to the hydraulic fluid loss procedure since the unsafe condition still existed which then directed us to the hydraulic caution procedure. Procedure then sent us to hydraulic procedure #1 for hydraulic fluid loss with both main and emergency still being in the green. Procedure called for the emergency gear handle to be pulled and gear was safely extended. Contacted dispatch to discuss further action and decided a return to ZZZ was best option with 12000 ft of runway and procedure calling for a no-flap landing and to expect abrupt loss of braking after the inboard/outboard brake pressure drops. Dispatch ran the fuel numbers to return to ZZZ. We then declared an emergency and returned to ZZZ. Landing went as planned and we stopped on the runway to be towed in to the gate. After shutdown of the aircraft; noticed circuit breaker F7 was tripped which was for the hydraulic landing gear control. We did not notice it in-flight and it was not mentioned in the emergency non-normal procedure. Whether or not this would have helped is unknown. The entire crew in my mind did a wonderful job with a safe outcome accomplished. Supplemental information from acn 810267: the aircraft reached cruising altitude and the captain chimed. I gave electronic devices announcement and began beverage service. Captain called and advised that they were running test on the landing gear. He called back and stated that we were under an emergency and that we would be turning back to ZZZ. He made an announcement to the passenger and informed them that it was purely precautionary. I prepared the cabin and collected the beverage supplies I have passed out. A couple of the passenger were very nervous. The others coped quite well. We landed in ZZZ and was met by emergency equipment. The captain advised them that everything was fine and they were no longer needed. They left and the aircraft was towed to gate. I informed the passenger they had been rebooked on the next available flight per the information given to the captain by the ground crew. The passenger deplaned. The maintenance crew came on board and the captain explained to them what happened. The flight crew and I deplaned. They called dispatch and did their reports. I called crew scheduling and was told I could leave but would remain on call until my scheduled time I would have returned to ZZZ.

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Original NASA ASRS Text

Title: SF340 CREW REPORT LANDING GEAR ANOMALY AND HYDRAULIC FLUID LOSS IN CRUISE THAT RESULTS IN DIVERSION AND MANUAL GEAR EXTENSION.

Narrative: DURING CRUISE AT 16000 FT; GEAR UNSAFE LIGHT ILLUMINATED. FOLLOWED EMER NON-NORMAL PROC FOR GEAR-UP UNSAFE CONDITION. PROC CALLED FOR THE GEAR TO BE RECYCLED. WHEN GEAR WAS PLACED IN THE DOWN POS; WE COULD HEAR THE HYD PUMP RUNNING BUT NO VERBAL INDICATION OF THE GEAR EXTENDING. AFTER ABOUT 1 MIN WITH NO GEAR DOWN LIGHTS ILLUMINATED; NOTICED HYD QUANTITY INDICATIONS DECREASING RAPIDLY. WITH NO DIRECTION IN THE GEAR UP UNSAFE POS PROC FOR THIS SITUATION; WE TURNED OFF THE HYD PUMP. WITH THE GEAR UP UNSAFE PROC ENDING AT THIS POINT WITH THE GEAR DOWN; WE PROCEEDED TO THE HYD FLUID LOSS PROC SINCE THE UNSAFE CONDITION STILL EXISTED WHICH THEN DIRECTED US TO THE HYD CAUTION PROC. PROC THEN SENT US TO HYD PROC #1 FOR HYD FLUID LOSS WITH BOTH MAIN AND EMER STILL BEING IN THE GREEN. PROC CALLED FOR THE EMER GEAR HANDLE TO BE PULLED AND GEAR WAS SAFELY EXTENDED. CONTACTED DISPATCH TO DISCUSS FURTHER ACTION AND DECIDED A RETURN TO ZZZ WAS BEST OPTION WITH 12000 FT OF RWY AND PROC CALLING FOR A NO-FLAP LNDG AND TO EXPECT ABRUPT LOSS OF BRAKING AFTER THE INBOARD/OUTBOARD BRAKE PRESSURE DROPS. DISPATCH RAN THE FUEL NUMBERS TO RETURN TO ZZZ. WE THEN DECLARED AN EMER AND RETURNED TO ZZZ. LNDG WENT AS PLANNED AND WE STOPPED ON THE RWY TO BE TOWED IN TO THE GATE. AFTER SHUTDOWN OF THE ACFT; NOTICED CIRCUIT BREAKER F7 WAS TRIPPED WHICH WAS FOR THE HYD LNDG GEAR CTL. WE DID NOT NOTICE IT INFLT AND IT WAS NOT MENTIONED IN THE EMER NON-NORMAL PROC. WHETHER OR NOT THIS WOULD HAVE HELPED IS UNKNOWN. THE ENTIRE CREW IN MY MIND DID A WONDERFUL JOB WITH A SAFE OUTCOME ACCOMPLISHED. SUPPLEMENTAL INFO FROM ACN 810267: THE ACFT REACHED CRUISING ALT AND THE CAPT CHIMED. I GAVE ELECTRONIC DEVICES ANNOUNCEMENT AND BEGAN BEVERAGE SVC. CAPT CALLED AND ADVISED THAT THEY WERE RUNNING TEST ON THE LNDG GEAR. HE CALLED BACK AND STATED THAT WE WERE UNDER AN EMER AND THAT WE WOULD BE TURNING BACK TO ZZZ. HE MADE AN ANNOUNCEMENT TO THE PAX AND INFORMED THEM THAT IT WAS PURELY PRECAUTIONARY. I PREPARED THE CABIN AND COLLECTED THE BEVERAGE SUPPLIES I HAVE PASSED OUT. A COUPLE OF THE PAX WERE VERY NERVOUS. THE OTHERS COPED QUITE WELL. WE LANDED IN ZZZ AND WAS MET BY EMER EQUIP. THE CAPT ADVISED THEM THAT EVERYTHING WAS FINE AND THEY WERE NO LONGER NEEDED. THEY LEFT AND THE ACFT WAS TOWED TO GATE. I INFORMED THE PAX THEY HAD BEEN REBOOKED ON THE NEXT AVAILABLE FLT PER THE INFO GIVEN TO THE CAPT BY THE GND CREW. THE PAX DEPLANED. THE MAINT CREW CAME ON BOARD AND THE CAPT EXPLAINED TO THEM WHAT HAPPENED. THE FLT CREW AND I DEPLANED. THEY CALLED DISPATCH AND DID THEIR RPTS. I CALLED CREW SCHEDULING AND WAS TOLD I COULD LEAVE BUT WOULD REMAIN ON CALL UNTIL MY SCHEDULED TIME I WOULD HAVE RETURNED TO ZZZ.

Data retrieved from NASA's ASRS site as of May 2009 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.