Narrative:

Captain engaged FMS/autoplt so as to utilize VNAV and LNAV simultaneous with a leveloff. Given heading change for spacing, aircraft failed to level off/capture the FL210 setting. We did the double hand point at the MCP, saw LNAV and VNAV on the FMA (or so we thought). No contact from ARTCC as to altitude deviation. Figured it was something we did as a crew, not the aircraft's fault. Captain had 27 hours in aircraft, I had 175.

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Original NASA ASRS Text

Title: ALT OVERSHOT BY FLT CREW IN A B737-800 WHEN PROGRAMMING THE FMS INCORRECTLY ON FREQ WITH ZBW, MA.

Narrative: CAPT ENGAGED FMS/AUTOPLT SO AS TO UTILIZE VNAV AND LNAV SIMULTANEOUS WITH A LEVELOFF. GIVEN HDG CHANGE FOR SPACING, ACFT FAILED TO LEVEL OFF/CAPTURE THE FL210 SETTING. WE DID THE DOUBLE HAND POINT AT THE MCP, SAW LNAV AND VNAV ON THE FMA (OR SO WE THOUGHT). NO CONTACT FROM ARTCC AS TO ALTDEV. FIGURED IT WAS SOMETHING WE DID AS A CREW, NOT THE ACFT'S FAULT. CAPT HAD 27 HRS IN ACFT, I HAD 175.

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.