Narrative:

Flying the koksy 1A arrival into bru, we were deviating around buildups visually between kerky and bruno as approach gave us descent to an altitude, I believe 4000 ft, and altimeter '995.' I read back '2995' and she did not correct me. I felt uncomfortable, so I picked up the paper with the ATIS on it and noted 995. Somehow, I still did not relate that the setting was hecto pascals. We accepted a turn downwind, followed by a turn to '220 degrees, descend to 2000 ft, cleared for ILS runway 25L.' on the intercept leg I noticed that the leg from final approach to the runway was not showing on the HSI, so I loaded it into the computer. When I looked up a few seconds later I discovered we were flying parallel to final and had descended below 2000 ft, although we were not on either the GS or localizer. I asked the copilot, who was hand flying, to stop the descent just as the approach controller told us we were low and 1/2 mi north of the localizer. She gave us an intercept heading and told us to maintain 1500 ft and that we would intercept in the vicinity of the LOM. She also gave us the altimeter setting once more as '995' as we turned to intercept we saw the runway approximately 4 mi ahead. Our altitude sagged a little at this time to about 1400 ft indicated and I crosschecked the radio altimeter which showed 800 ft. We intercepted the GS at approximately 1400 ft indicated and made a normal landing. I believe this problem arose primarily as a result of fatigue with both pilots and a series of errors that were linking up in a dangerous pattern. I believe the altimeter error could have been prevented if the controller had used 4 digits for the setting, as '0995.' in the us controllers, and pilots, often drop the '2' in front of setting, saying '995' instead of '2995,' this caused us to be receptive to 995 being an inches setting rather than hecto pascals. In addition, I expect to be more alert to coplts, even though highly experienced, being affected by fatigue.

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Original NASA ASRS Text

Title: ALTDEV DURING APCH CAUSED IN PART BY WRONG ALTIMETER SETTING.

Narrative: FLYING THE KOKSY 1A ARR INTO BRU, WE WERE DEVIATING AROUND BUILDUPS VISUALLY BTWN KERKY AND BRUNO AS APCH GAVE US DSCNT TO AN ALT, I BELIEVE 4000 FT, AND ALTIMETER '995.' I READ BACK '2995' AND SHE DID NOT CORRECT ME. I FELT UNCOMFORTABLE, SO I PICKED UP THE PAPER WITH THE ATIS ON IT AND NOTED 995. SOMEHOW, I STILL DID NOT RELATE THAT THE SETTING WAS HECTO PASCALS. WE ACCEPTED A TURN DOWNWIND, FOLLOWED BY A TURN TO '220 DEGS, DSND TO 2000 FT, CLRED FOR ILS RWY 25L.' ON THE INTERCEPT LEG I NOTICED THAT THE LEG FROM FINAL APCH TO THE RWY WAS NOT SHOWING ON THE HSI, SO I LOADED IT INTO THE COMPUTER. WHEN I LOOKED UP A FEW SECONDS LATER I DISCOVERED WE WERE FLYING PARALLEL TO FINAL AND HAD DSNDED BELOW 2000 FT, ALTHOUGH WE WERE NOT ON EITHER THE GS OR LOC. I ASKED THE COPLT, WHO WAS HAND FLYING, TO STOP THE DSCNT JUST AS THE APCH CTLR TOLD US WE WERE LOW AND 1/2 MI N OF THE LOC. SHE GAVE US AN INTERCEPT HDG AND TOLD US TO MAINTAIN 1500 FT AND THAT WE WOULD INTERCEPT IN THE VICINITY OF THE LOM. SHE ALSO GAVE US THE ALTIMETER SETTING ONCE MORE AS '995' AS WE TURNED TO INTERCEPT WE SAW THE RWY APPROX 4 MI AHEAD. OUR ALT SAGGED A LITTLE AT THIS TIME TO ABOUT 1400 FT INDICATED AND I XCHKED THE RADIO ALTIMETER WHICH SHOWED 800 FT. WE INTERCEPTED THE GS AT APPROX 1400 FT INDICATED AND MADE A NORMAL LNDG. I BELIEVE THIS PROB AROSE PRIMARILY AS A RESULT OF FATIGUE WITH BOTH PLTS AND A SERIES OF ERRORS THAT WERE LINKING UP IN A DANGEROUS PATTERN. I BELIEVE THE ALTIMETER ERROR COULD HAVE BEEN PREVENTED IF THE CTLR HAD USED 4 DIGITS FOR THE SETTING, AS '0995.' IN THE US CTLRS, AND PLTS, OFTEN DROP THE '2' IN FRONT OF SETTING, SAYING '995' INSTEAD OF '2995,' THIS CAUSED US TO BE RECEPTIVE TO 995 BEING AN INCHES SETTING RATHER THAN HECTO PASCALS. IN ADDITION, I EXPECT TO BE MORE ALERT TO COPLTS, EVEN THOUGH HIGHLY EXPERIENCED, BEING AFFECTED BY FATIGUE.

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.