Narrative:

After being cleared for ILS runway 27 from 4000 ft MSL and 180 KIAS, with clearance to maintain 2500 MSL until jumar, captain began descent while inbound on 273 degree course. Assigned 170 KIAS until crossing shape. Captain called for flaps 10 degrees and I thought he said flaps 30 degrees. I repeated 30 degrees and we both looked to indicator and then moved flap lever to 10 degrees. Flaps had not traveled past 10 degree position. Warning horn sounded continuously while lever was in 30 degrees. Horn stopped when positioned lever to 10 degrees. Horn is normal indication aural warning since landing gear was not down. Horn silenced when lever was positioned to 10 degrees. This occurred just as we were descending through 3500 ft MSL. I believe the misunderstanding and the horn caused us to miss the 1000 ft prior callout. I then (after horn silenced and flaps correctly positioned) noticed the altitude was 2200 ft and alerted captain 2500 ft until jumar. Captain climbed immediately (lowest altitude was 2100 ft ) to 2500 ft MSL. Just after level off, we captured glide slope. During climb to 2500 ft ATC questioned airspeed. Airspeed dropped to 165 KTS during climb and was back to 170 KTS when ATC queried. There were no apparent traffic conflicts, no aircraft in sight or on TCASII. Flight continue safely to fll. Cause: first officer misunderstanding flaps, lead to horn, lead to discerning problem, lead to altitude/airspeed deviation. To correct/prevent reoccurrence--speak louder/listen better.

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Original NASA ASRS Text

Title: FLT CREW DISTR WHEN FLAP SETTING WAS INCORRECTLY SET TO 30 DEGS WITH THE LNDG GEAR STILL IN THE UP POS.

Narrative: AFTER BEING CLRED FOR ILS RWY 27 FROM 4000 FT MSL AND 180 KIAS, WITH CLRNC TO MAINTAIN 2500 MSL UNTIL JUMAR, CAPT BEGAN DSCNT WHILE INBOUND ON 273 DEG COURSE. ASSIGNED 170 KIAS UNTIL XING SHAPE. CAPT CALLED FOR FLAPS 10 DEGS AND I THOUGHT HE SAID FLAPS 30 DEGS. I REPEATED 30 DEGS AND WE BOTH LOOKED TO INDICATOR AND THEN MOVED FLAP LEVER TO 10 DEGS. FLAPS HAD NOT TRAVELED PAST 10 DEG POS. WARNING HORN SOUNDED CONTINUOUSLY WHILE LEVER WAS IN 30 DEGS. HORN STOPPED WHEN POSITIONED LEVER TO 10 DEGS. HORN IS NORMAL INDICATION AURAL WARNING SINCE LNDG GEAR WAS NOT DOWN. HORN SILENCED WHEN LEVER WAS POSITIONED TO 10 DEGS. THIS OCCURRED JUST AS WE WERE DSNDING THROUGH 3500 FT MSL. I BELIEVE THE MISUNDERSTANDING AND THE HORN CAUSED US TO MISS THE 1000 FT PRIOR CALLOUT. I THEN (AFTER HORN SILENCED AND FLAPS CORRECTLY POSITIONED) NOTICED THE ALT WAS 2200 FT AND ALERTED CAPT 2500 FT UNTIL JUMAR. CAPT CLBED IMMEDIATELY (LOWEST ALT WAS 2100 FT ) TO 2500 FT MSL. JUST AFTER LEVEL OFF, WE CAPTURED GLIDE SLOPE. DURING CLB TO 2500 FT ATC QUESTIONED AIRSPD. AIRSPD DROPPED TO 165 KTS DURING CLB AND WAS BACK TO 170 KTS WHEN ATC QUERIED. THERE WERE NO APPARENT TFC CONFLICTS, NO ACFT IN SIGHT OR ON TCASII. FLT CONTINUE SAFELY TO FLL. CAUSE: FO MISUNDERSTANDING FLAPS, LEAD TO HORN, LEAD TO DISCERNING PROB, LEAD TO ALT/AIRSPD DEV. TO CORRECT/PREVENT REOCCURRENCE--SPEAK LOUDER/LISTEN BETTER.

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.