Narrative:

I was the captain and PF, and my first officer was the PNF. The flight was in solid IMC and in driving rain. On the ILS runway 4 approach to bos, approaching the glide path, I called for gear down. PNF placed the gear handle down and almost immediately the master caution light came on, with the hydraulic light on. I immediately turned the hydraulic pump switch off and checked the emergency and main accumulator pressure. The main was at zero and emr at 3000. Landing gear indications were nose safe and mains unsafe, and light was on in gear handle. The airspeed was 170 KTS. The flaps were left where they were, which was up. Having completed the memory items, I initiated a go around. I did not declare an emergency. I told PNF that I would retain control of the aircraft, and assume communication duties, and that he was to review the epc for hydraulic light on. He did this while I re-engaged autoplt and communicated our problem with ATC. At this point, he misread the epc and called for the emergency landing handle to be pulled, and I agreed to this. The handle was pulled and we got 3 green lights and light out in the handle. I informed ATC we could accept another approach and I called for the full hydraulic checklist. PNF got this checklist out and read it out loud. The emergency pressure was normal, but the main was low, so he checked the hydraulic quantity indicator and the brake accumulator pressure, which were normal. He then had me check circuit breakers xa, xb. These were in, but I pulled and reset them. I turned the hydraulic pump switch from off to override to off, and this action returned the main accumulator pressure to normal, and regained normal operation of pump. I informed ATC that we had normal indications in cockpit and that we would be making a normal approach and landing.

Related reports:

Google
 

Original NASA ASRS Text

Title: AN ACR CREW WITH A LNDG GEAR AND HYD PROB MISREADS THE APPROPRIATE CHKLIST BUT IS ABLE TO OVERCOME THE ERROR COMPLETING THE FLT WITH A NORMAL LNDG.

Narrative: I WAS THE CAPT AND PF, AND MY FO WAS THE PNF. THE FLT WAS IN SOLID IMC AND IN DRIVING RAIN. ON THE ILS RWY 4 APCH TO BOS, APCHING THE GLIDE PATH, I CALLED FOR GEAR DOWN. PNF PLACED THE GEAR HANDLE DOWN AND ALMOST IMMEDIATELY THE MASTER CAUTION LIGHT CAME ON, WITH THE HYD LIGHT ON. I IMMEDIATELY TURNED THE HYD PUMP SWITCH OFF AND CHKED THE EMER AND MAIN ACCUMULATOR PRESSURE. THE MAIN WAS AT ZERO AND EMR AT 3000. LNDG GEAR INDICATIONS WERE NOSE SAFE AND MAINS UNSAFE, AND LIGHT WAS ON IN GEAR HANDLE. THE AIRSPD WAS 170 KTS. THE FLAPS WERE LEFT WHERE THEY WERE, WHICH WAS UP. HAVING COMPLETED THE MEMORY ITEMS, I INITIATED A GAR. I DID NOT DECLARE AN EMER. I TOLD PNF THAT I WOULD RETAIN CTL OF THE ACFT, AND ASSUME COM DUTIES, AND THAT HE WAS TO REVIEW THE EPC FOR HYD LIGHT ON. HE DID THIS WHILE I RE-ENGAGED AUTOPLT AND COMMUNICATED OUR PROB WITH ATC. AT THIS POINT, HE MISREAD THE EPC AND CALLED FOR THE EMER LNDG HANDLE TO BE PULLED, AND I AGREED TO THIS. THE HANDLE WAS PULLED AND WE GOT 3 GREEN LIGHTS AND LIGHT OUT IN THE HANDLE. I INFORMED ATC WE COULD ACCEPT ANOTHER APCH AND I CALLED FOR THE FULL HYD CHKLIST. PNF GOT THIS CHKLIST OUT AND READ IT OUT LOUD. THE EMER PRESSURE WAS NORMAL, BUT THE MAIN WAS LOW, SO HE CHKED THE HYD QUANTITY INDICATOR AND THE BRAKE ACCUMULATOR PRESSURE, WHICH WERE NORMAL. HE THEN HAD ME CHK CIRCUIT BREAKERS XA, XB. THESE WERE IN, BUT I PULLED AND RESET THEM. I TURNED THE HYD PUMP SWITCH FROM OFF TO OVERRIDE TO OFF, AND THIS ACTION RETURNED THE MAIN ACCUMULATOR PRESSURE TO NORMAL, AND REGAINED NORMAL OP OF PUMP. I INFORMED ATC THAT WE HAD NORMAL INDICATIONS IN COCKPIT AND THAT WE WOULD BE MAKING A NORMAL APCH AND LNDG.

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.