Narrative:

I am the first officer reporting and the PNF. The event occurred at approximately XA00Z, ZNY, frequency 132.15. We were cleared to 10000 ft en route to camrn intersection. Passing through 8300 ft we noted the deviation and began correcting back to 10000 ft when queried by the controller as to our altitude. We were subsequently cleared to 9000 ft and leveled off at that altitude. When initially cleared to 10000 ft, I inadvertently set in 1000 ft. The PF acknowledged my 10000 ft callout. Supplemental information from acn 384091: after receiving clearance to 10000 ft, first officer inadvertently selected 1000 ft. Captain was busy on CDU and briefly glanced up to verify, but did not see error. ATC questioned altitude during descent and captain corrected to new assigned altitude.

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Original NASA ASRS Text

Title: AN ACR B757 FLC DSNDED BELOW THEIR ASSIGNED ALT WHEN THE FO SET THE WRONG ALT IN THE ALT ALERTER.

Narrative: I AM THE FO RPTING AND THE PNF. THE EVENT OCCURRED AT APPROX XA00Z, ZNY, FREQ 132.15. WE WERE CLRED TO 10000 FT ENRTE TO CAMRN INTXN. PASSING THROUGH 8300 FT WE NOTED THE DEV AND BEGAN CORRECTING BACK TO 10000 FT WHEN QUERIED BY THE CTLR AS TO OUR ALT. WE WERE SUBSEQUENTLY CLRED TO 9000 FT AND LEVELED OFF AT THAT ALT. WHEN INITIALLY CLRED TO 10000 FT, I INADVERTENTLY SET IN 1000 FT. THE PF ACKNOWLEDGED MY 10000 FT CALLOUT. SUPPLEMENTAL INFO FROM ACN 384091: AFTER RECEIVING CLRNC TO 10000 FT, FO INADVERTENTLY SELECTED 1000 FT. CAPT WAS BUSY ON CDU AND BRIEFLY GLANCED UP TO VERIFY, BUT DID NOT SEE ERROR. ATC QUESTIONED ALT DURING DSCNT AND CAPT CORRECTED TO NEW ASSIGNED ALT.

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.