|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Locale Reference||airport : bos.airport|
|Controlling Facilities||tracon : a90.tracon|
tower : bos.tower
|Operator||common carrier : air carrier|
|Make Model Name||Saab-Scania Undifferentiated or Other Model|
|Operating Under FAR Part||Part 121|
|Navigation In Use||ils localizer & glide slope : 4l|
|Flight Phase||descent : approach|
|Route In Use||approach : instrument precision|
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Anomaly||aircraft equipment problem : less severe|
other anomaly other
|Independent Detector||aircraft equipment other aircraft equipment : lndg position indicator hyd pressure indicator|
other flight crewa
other flight crewb
|Resolutory Action||aircraft : equipment problem dissipated|
flight crew : executed go around
flight crew : overcame equipment problem
Flight Crew Human Performance
|Primary Problem||Flight Crew Human Performance|
I was the PNF. On the ILS runway 4R approach in bos, captain called for gear down. We had a master caution alert. I checked the central warning panel stated hydraulic light on and canceled the alert. The gear in-transit and nose gear lights were on, but the main gear lights were not. I could see that the main accelerator pressure indicated zero. Captain instructed me to contact tower and tell them we were going around due to an abnormal indication. Captain stated he would continue to fly and talk on the radio while I worked the checklist. Captain handed me the epc and I read the hydraulic light on procedure out loud from the epc reading the first item I noted the captain had initially turned the hydraulic pump to off. I read the second item emergency and main accelerator pressure check (if emergency and main accelerator pressure both low, below 2000 psi). I looked at the hydraulic panel and could see the main accelerator indicated zero. The captain concurred and I continued the checklist. Airspeed was already below 200 KIAS and we did not change flap position. Landing gear handle was down. The emergency landing handle was pulled. We then had safe gear indications. Captain instructed me to make a PA and contact bos operation and advise them of our situation. While being vectored for a second approach captain called for the hydraulic checklist in aom vol 1. As I read the procedure aloud we noted the emergency accelerator indicated normal approximately 3000 psi. I continued to read procedure for low main and normal emergency accelerator pressure. The checklist called for hydraulic circuit breakers to be reset. Captain reset the specified circuit breaker and we regained function of the hydraulic pump. At that point we had normal indications and were able to cancel emergency.
Original NASA ASRS Text
Title: SAAB 340 FLC MADE GAR IN ORDER TO TROUBLESHOOT AN ABNORMAL LNDG GEAR EXTENSION PROB. SUBSEQUENTLY, PROB WAS RESOLVED AFTER CORRECT PROCS WERE USED PER ACFT OPERATING MANUAL.
Narrative: I WAS THE PNF. ON THE ILS RWY 4R APCH IN BOS, CAPT CALLED FOR GEAR DOWN. WE HAD A MASTER CAUTION ALERT. I CHKED THE CENTRAL WARNING PANEL STATED HYD LIGHT ON AND CANCELED THE ALERT. THE GEAR IN-TRANSIT AND NOSE GEAR LIGHTS WERE ON, BUT THE MAIN GEAR LIGHTS WERE NOT. I COULD SEE THAT THE MAIN ACCELERATOR PRESSURE INDICATED ZERO. CAPT INSTRUCTED ME TO CONTACT TWR AND TELL THEM WE WERE GOING AROUND DUE TO AN ABNORMAL INDICATION. CAPT STATED HE WOULD CONTINUE TO FLY AND TALK ON THE RADIO WHILE I WORKED THE CHKLIST. CAPT HANDED ME THE EPC AND I READ THE HYD LIGHT ON PROC OUT LOUD FROM THE EPC READING THE FIRST ITEM I NOTED THE CAPT HAD INITIALLY TURNED THE HYD PUMP TO OFF. I READ THE SECOND ITEM EMER AND MAIN ACCELERATOR PRESSURE CHK (IF EMER AND MAIN ACCELERATOR PRESSURE BOTH LOW, BELOW 2000 PSI). I LOOKED AT THE HYD PANEL AND COULD SEE THE MAIN ACCELERATOR INDICATED ZERO. THE CAPT CONCURRED AND I CONTINUED THE CHKLIST. AIRSPD WAS ALREADY BELOW 200 KIAS AND WE DID NOT CHANGE FLAP POS. LNDG GEAR HANDLE WAS DOWN. THE EMER LNDG HANDLE WAS PULLED. WE THEN HAD SAFE GEAR INDICATIONS. CAPT INSTRUCTED ME TO MAKE A PA AND CONTACT BOS OP AND ADVISE THEM OF OUR SIT. WHILE BEING VECTORED FOR A SECOND APCH CAPT CALLED FOR THE HYD CHKLIST IN AOM VOL 1. AS I READ THE PROC ALOUD WE NOTED THE EMER ACCELERATOR INDICATED NORMAL APPROX 3000 PSI. I CONTINUED TO READ PROC FOR LOW MAIN AND NORMAL EMER ACCELERATOR PRESSURE. THE CHKLIST CALLED FOR HYD CIRCUIT BREAKERS TO BE RESET. CAPT RESET THE SPECIFIED CIRCUIT BREAKER AND WE REGAINED FUNCTION OF THE HYD PUMP. AT THAT POINT WE HAD NORMAL INDICATIONS AND WERE ABLE TO CANCEL EMER.
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.