Wrong altimeter setting confuses PIC of a B737 during an approach in inclement WX to stl, mo.

Attributes
ACN	539335
Time
Date	200202
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : stl.airport
State Reference	MO
Altitude	msl bound lower : 9600 msl bound upper : 10000
Environment
Flight Conditions	IMC
Weather Elements	Fog Ice Snow other
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : t75.tracon tower : stl.tower
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer only : 30l other
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 23000 flight time type : 19000
ASRS Report	539335
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	altitude deviation : overshoot inflight encounter : weather non adherence : published procedure non adherence : company policies non adherence : clearance other anomaly other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	other
Supplementary
Problem Areas	ATC Facility Weather Flight Crew Human Performance ATC Human Performance Environmental Factor
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Approaching stl, about 100 mi out, I tuned and copied the current ATIS. I copied the altimeter as 30.44 (heard it twice and remembered thinking that it seemed awfully high for such lousy WX). ATIS said lndgs -- ILS runway 24 or runway 30R, departures runway 30L. We completed the approach/descent checklist and briefed the runway 30R ILS approach. I don't remember if we ever leveled off during the descent, but if we did, we were 400 ft low due to the incorrect altimeter. We probably stopped at 10000 ft to low, but would have actually been at 9600 ft about 250 KTS. (As we found out later at the gate, actual altimeter was 30.04.) approach turned us on base, then dogleg to final, and cleared us for ILS runway 30L. I confirmed the change from runway 30R to runway 30L and we scrambled to return and rebrief for the runway 30L ILS. (This is a very common problem at stl -- initial assignment is to one runway, then cleared for the parallel runway turning on final.) very soon thereafter, we got an OM flash and tone, but thought it was the runway 30R beacon since my altimeter read about 2500 ft instead about 2150 ft. (We were on GS at this point.) at the 1000 ft AGL call (about 1600 ft MSL) we began to realize there was a fairly large difference between the bar altimeter (1600 ft = 1000 ft AGL) and the radar altimeter reading (600 ft). Since we were on GS and now had the end of the runway in sight, we continued to an uneventful landing. At the gate, I checked the ATIS again, but it had been updated and was giving 30.04. I don't honestly know if I copied the wrong altimeter off the ATIS or if the wrong altimeter was given by the ATIS. Approach never questioned our altitude and I don't ever remember hearing approach give out an altimeter. I missed the obvious clue over the OM, but was still a little behind due to the last min runway change and had just returned my navigation from the VOR frequency needed to identify the step-down at joice. I was too quick to assume we received the runway 30R marker, and shortly after wondering why we didn't get the runway 30L marker, we did see the runway and did the 100 AGL call.

Original NASA ASRS Text

Title: WRONG ALTIMETER SETTING CONFUSES PIC OF A B737 DURING AN APCH IN INCLEMENT WX TO STL, MO.

Narrative: APCHING STL, ABOUT 100 MI OUT, I TUNED AND COPIED THE CURRENT ATIS. I COPIED THE ALTIMETER AS 30.44 (HEARD IT TWICE AND REMEMBERED THINKING THAT IT SEEMED AWFULLY HIGH FOR SUCH LOUSY WX). ATIS SAID LNDGS -- ILS RWY 24 OR RWY 30R, DEPS RWY 30L. WE COMPLETED THE APCH/DSCNT CHKLIST AND BRIEFED THE RWY 30R ILS APCH. I DON'T REMEMBER IF WE EVER LEVELED OFF DURING THE DSCNT, BUT IF WE DID, WE WERE 400 FT LOW DUE TO THE INCORRECT ALTIMETER. WE PROBABLY STOPPED AT 10000 FT TO LOW, BUT WOULD HAVE ACTUALLY BEEN AT 9600 FT ABOUT 250 KTS. (AS WE FOUND OUT LATER AT THE GATE, ACTUAL ALTIMETER WAS 30.04.) APCH TURNED US ON BASE, THEN DOGLEG TO FINAL, AND CLRED US FOR ILS RWY 30L. I CONFIRMED THE CHANGE FROM RWY 30R TO RWY 30L AND WE SCRAMBLED TO RETURN AND REBRIEF FOR THE RWY 30L ILS. (THIS IS A VERY COMMON PROB AT STL -- INITIAL ASSIGNMENT IS TO ONE RWY, THEN CLRED FOR THE PARALLEL RWY TURNING ON FINAL.) VERY SOON THEREAFTER, WE GOT AN OM FLASH AND TONE, BUT THOUGHT IT WAS THE RWY 30R BEACON SINCE MY ALTIMETER READ ABOUT 2500 FT INSTEAD ABOUT 2150 FT. (WE WERE ON GS AT THIS POINT.) AT THE 1000 FT AGL CALL (ABOUT 1600 FT MSL) WE BEGAN TO REALIZE THERE WAS A FAIRLY LARGE DIFFERENCE BTWN THE BAR ALTIMETER (1600 FT = 1000 FT AGL) AND THE RADAR ALTIMETER READING (600 FT). SINCE WE WERE ON GS AND NOW HAD THE END OF THE RWY IN SIGHT, WE CONTINUED TO AN UNEVENTFUL LNDG. AT THE GATE, I CHKED THE ATIS AGAIN, BUT IT HAD BEEN UPDATED AND WAS GIVING 30.04. I DON'T HONESTLY KNOW IF I COPIED THE WRONG ALTIMETER OFF THE ATIS OR IF THE WRONG ALTIMETER WAS GIVEN BY THE ATIS. APCH NEVER QUESTIONED OUR ALT AND I DON'T EVER REMEMBER HEARING APCH GIVE OUT AN ALTIMETER. I MISSED THE OBVIOUS CLUE OVER THE OM, BUT WAS STILL A LITTLE BEHIND DUE TO THE LAST MIN RWY CHANGE AND HAD JUST RETURNED MY NAV FROM THE VOR FREQ NEEDED TO IDENT THE STEP-DOWN AT JOICE. I WAS TOO QUICK TO ASSUME WE RECEIVED THE RWY 30R MARKER, AND SHORTLY AFTER WONDERING WHY WE DIDN'T GET THE RWY 30L MARKER, WE DID SEE THE RWY AND DID THE 100 AGL CALL.

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.