Narrative:

While descending into valdosta on a visual approach, hydraulic light on multiple alarm panel lit, accompanied by a single chime. The captain was the PF and the autoplt was engaged. I canceled the alarm and looked at the hydraulic panel to determine the cause of the problem. The low pressure light was illuminated, as well as the reservoir low level light. The electric pump had turned on. The hydraulic gauges for the green system showed no pressure and no fluid remaining. I informed the captain that the alarm had indicated a loss of the green hydraulic system. He called for the loss of green system checklist. I ran the checklist while he called approach and got clearance to level at 5000 ft. We proceeded to enter holding over the valdosta VOR. We determined we had lost our outboard flaps, brakes, 1 rudder system, and would have to free fall the landing gear. Flight control was contacted, who advised us to land in valdosta if we were comfortable with it. After a brief discussion, we decided to land in valdosta. We proceeded to free fall the gear, using the checklist, at 5000 ft. Gear came down without incident. After another brief discussion, we declined to declare an emergency, after which the captain briefed the flight attendant. We then decided to proceed to the airport and was cleared for a visual approach. While inbound, I realized that using flaps would cause a flap disagreement, and the captain asked me to get the flap disagreement checklist. (We had already determined valdosta had adequate runway length for landing). I got the checklist and reviewed it. The checklist advised not to move the flap selector after a disagreement took place. We decided to disregard this, as we knew the disagreement was caused by a hydraulic problem, not a flap computer problem. Flap disagreement checklist advised of appropriate speed to add to vref. After being cleared to land, we landed without, incident on runway 35. After reaching the gate and shutting down, the captain and I discussed apparent ambiguities in the loss of green system checklist. The checklist does not specify whether full flaps should be used, and does not say what flap setting the runway length chart in the checklist is calibrated for. No mention of the flap disagreement checklist is made, nor is any mention of airspeed adjustments to vref. This is found only in the disagreement checklist. An unusual occurrence report was filed the next day with the company. Both the captain and myself feel the checklist needs improvement to remove ambiguities, and to prevent crew decisions which deliberately contradict an approved checklist.

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Original NASA ASRS Text

Title: AN ACR FLC FLYING EMB120 NEAR VLD EXPERIENCED TOTAL LOSS OF GREEN HYD SYS RESULTING IN EMER GEAR EXTENSION AND EMER LNDG.

Narrative: WHILE DSNDING INTO VALDOSTA ON A VISUAL APCH, HYD LIGHT ON MULTIPLE ALARM PANEL LIT, ACCOMPANIED BY A SINGLE CHIME. THE CAPT WAS THE PF AND THE AUTOPLT WAS ENGAGED. I CANCELED THE ALARM AND LOOKED AT THE HYD PANEL TO DETERMINE THE CAUSE OF THE PROB. THE LOW PRESSURE LIGHT WAS ILLUMINATED, AS WELL AS THE RESERVOIR LOW LEVEL LIGHT. THE ELECTRIC PUMP HAD TURNED ON. THE HYD GAUGES FOR THE GREEN SYS SHOWED NO PRESSURE AND NO FLUID REMAINING. I INFORMED THE CAPT THAT THE ALARM HAD INDICATED A LOSS OF THE GREEN HYD SYS. HE CALLED FOR THE LOSS OF GREEN SYS CHKLIST. I RAN THE CHKLIST WHILE HE CALLED APCH AND GOT CLRNC TO LEVEL AT 5000 FT. WE PROCEEDED TO ENTER HOLDING OVER THE VALDOSTA VOR. WE DETERMINED WE HAD LOST OUR OUTBOARD FLAPS, BRAKES, 1 RUDDER SYS, AND WOULD HAVE TO FREE FALL THE LNDG GEAR. FLT CTL WAS CONTACTED, WHO ADVISED US TO LAND IN VALDOSTA IF WE WERE COMFORTABLE WITH IT. AFTER A BRIEF DISCUSSION, WE DECIDED TO LAND IN VALDOSTA. WE PROCEEDED TO FREE FALL THE GEAR, USING THE CHKLIST, AT 5000 FT. GEAR CAME DOWN WITHOUT INCIDENT. AFTER ANOTHER BRIEF DISCUSSION, WE DECLINED TO DECLARE AN EMER, AFTER WHICH THE CAPT BRIEFED THE FLT ATTENDANT. WE THEN DECIDED TO PROCEED TO THE ARPT AND WAS CLRED FOR A VISUAL APCH. WHILE INBOUND, I REALIZED THAT USING FLAPS WOULD CAUSE A FLAP DISAGREEMENT, AND THE CAPT ASKED ME TO GET THE FLAP DISAGREEMENT CHKLIST. (WE HAD ALREADY DETERMINED VALDOSTA HAD ADEQUATE RWY LENGTH FOR LNDG). I GOT THE CHKLIST AND REVIEWED IT. THE CHKLIST ADVISED NOT TO MOVE THE FLAP SELECTOR AFTER A DISAGREEMENT TOOK PLACE. WE DECIDED TO DISREGARD THIS, AS WE KNEW THE DISAGREEMENT WAS CAUSED BY A HYD PROB, NOT A FLAP COMPUTER PROB. FLAP DISAGREEMENT CHKLIST ADVISED OF APPROPRIATE SPD TO ADD TO VREF. AFTER BEING CLRED TO LAND, WE LANDED WITHOUT, INCIDENT ON RWY 35. AFTER REACHING THE GATE AND SHUTTING DOWN, THE CAPT AND I DISCUSSED APPARENT AMBIGUITIES IN THE LOSS OF GREEN SYS CHKLIST. THE CHKLIST DOES NOT SPECIFY WHETHER FULL FLAPS SHOULD BE USED, AND DOES NOT SAY WHAT FLAP SETTING THE RWY LENGTH CHART IN THE CHKLIST IS CALIBRATED FOR. NO MENTION OF THE FLAP DISAGREEMENT CHKLIST IS MADE, NOR IS ANY MENTION OF AIRSPD ADJUSTMENTS TO VREF. THIS IS FOUND ONLY IN THE DISAGREEMENT CHKLIST. AN UNUSUAL OCCURRENCE RPT WAS FILED THE NEXT DAY WITH THE COMPANY. BOTH THE CAPT AND MYSELF FEEL THE CHKLIST NEEDS IMPROVEMENT TO REMOVE AMBIGUITIES, AND TO PREVENT CREW DECISIONS WHICH DELIBERATELY CONTRADICT AN APPROVED CHKLIST.

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.