Narrative:

I was flying and at cruise altitude I programmed the FMC to guide the autoplt to cross drako intersection below FL230 and above FL170 at 250 K. The right autoplt was in use in the cmd position. The mode control panel was set in LNAV and VNAV. After descending to FL260 ZDV cleared us for the profile descent into denver. I put 13,000' in the altitude box on the MCP. At approximately FL210 I tuned in the den ATIS, our radios started to get scratchy and we entered a band of turbulence. Our radar did not indicate heavy cells only light precipitation. At about this time the captain turned on our engine and wing anti-ice systems and shortly thereafter an 'ice detect' light indicated on our EICAS CRT. Approaching 19,000' the ATIS started coming through and shortly thereafter we started getting heavy static discharges and more turbulence. Somehow because of numerous distractions I did not detect that the aircraft had not leveled at 17,000' as programmed. All I remember is while copying the ATIS I heard center in the background telling us to climb immediately because of high terrain. To climb immediately because of high terrain. The captain immediately took over flying the aircraft, applied power, and climbed to approximately 17,000'. As I recall we were about 8 mi from drako when this incident occurred and I remember seeing 15,000 plus something on my altimeter. Before and after passing 17,000' we experienced a lot of dramatic static discharges around the nose of the aircraft that could have caused an electrical interruption to our FMC and the glitch that prevented the autoplt from leveling at 17,000'. Supplemental information from acn 116707: ZDV asked for our altitude. This alerted us that the aircraft had continued on down to 15,700 and 8.4 mi west of drako. ZDV advised that terrain in the area was about 12,000'. I initiated a climb to 17,000'. This was reached 4.4 mi west of drako. The autoplt VNAV had not captured at 17,000. At no time did we get a 'terrain' or 'pull up' alert or any indication on the tape altimeter. We had numerous static discharge off of the aircraft, during which the right engine oil pressure EICAS message came on. At that point the left engine oil pressure was 189 psi. The right oil pressure was about 115 psi and climbed to 185 psi over about 30 seconds. I suspect that one of the discharges may have been a lightning strike.

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Original NASA ASRS Text

Title: LGT IN AUTO DESCENT INTO DEN OVERSHOT CROSSING ALT. CENTER CTLR INTERVENED ACCOUNT TERRAIN.

Narrative: I WAS FLYING AND AT CRUISE ALT I PROGRAMMED THE FMC TO GUIDE THE AUTOPLT TO CROSS DRAKO INTXN BELOW FL230 AND ABOVE FL170 AT 250 K. THE RIGHT AUTOPLT WAS IN USE IN THE CMD POSITION. THE MODE CONTROL PANEL WAS SET IN LNAV AND VNAV. AFTER DESCENDING TO FL260 ZDV CLRED US FOR THE PROFILE DSCNT INTO DENVER. I PUT 13,000' IN THE ALT BOX ON THE MCP. AT APPROX FL210 I TUNED IN THE DEN ATIS, OUR RADIOS STARTED TO GET SCRATCHY AND WE ENTERED A BAND OF TURBULENCE. OUR RADAR DID NOT INDICATE HEAVY CELLS ONLY LIGHT PRECIPITATION. AT ABOUT THIS TIME THE CAPT TURNED ON OUR ENGINE AND WING ANTI-ICE SYSTEMS AND SHORTLY THEREAFTER AN 'ICE DETECT' LIGHT INDICATED ON OUR EICAS CRT. APCHING 19,000' THE ATIS STARTED COMING THROUGH AND SHORTLY THEREAFTER WE STARTED GETTING HEAVY STATIC DISCHARGES AND MORE TURBULENCE. SOMEHOW BECAUSE OF NUMEROUS DISTRACTIONS I DID NOT DETECT THAT THE ACFT HAD NOT LEVELED AT 17,000' AS PROGRAMMED. ALL I REMEMBER IS WHILE COPYING THE ATIS I HEARD CENTER IN THE BACKGROUND TELLING US TO CLIMB IMMEDIATELY BECAUSE OF HIGH TERRAIN. TO CLIMB IMMEDIATELY BECAUSE OF HIGH TERRAIN. THE CAPT IMMEDIATELY TOOK OVER FLYING THE ACFT, APPLIED POWER, AND CLIMBED TO APPROX 17,000'. AS I RECALL WE WERE ABOUT 8 MI FROM DRAKO WHEN THIS INCIDENT OCCURRED AND I REMEMBER SEEING 15,000 PLUS SOMETHING ON MY ALTIMETER. BEFORE AND AFTER PASSING 17,000' WE EXPERIENCED A LOT OF DRAMATIC STATIC DISCHARGES AROUND THE NOSE OF THE ACFT THAT COULD HAVE CAUSED AN ELECTRICAL INTERRUPTION TO OUR FMC AND THE GLITCH THAT PREVENTED THE AUTOPLT FROM LEVELING AT 17,000'. SUPPLEMENTAL INFORMATION FROM ACN 116707: ZDV ASKED FOR OUR ALT. THIS ALERTED US THAT THE ACFT HAD CONTINUED ON DOWN TO 15,700 AND 8.4 MI W OF DRAKO. ZDV ADVISED THAT TERRAIN IN THE AREA WAS ABOUT 12,000'. I INITIATED A CLIMB TO 17,000'. THIS WAS REACHED 4.4 MI W OF DRAKO. THE AUTOPLT VNAV HAD NOT CAPTURED AT 17,000. AT NO TIME DID WE GET A 'TERRAIN' OR 'PULL UP' ALERT OR ANY INDICATION ON THE TAPE ALTIMETER. WE HAD NUMEROUS STATIC DISCHARGE OFF OF THE ACFT, DURING WHICH THE RIGHT ENGINE OIL PRESSURE EICAS MESSAGE CAME ON. AT THAT POINT THE LEFT ENGINE OIL PRESSURE WAS 189 PSI. THE RIGHT OIL PRESSURE WAS ABOUT 115 PSI AND CLIMBED TO 185 PSI OVER ABOUT 30 SECONDS. I SUSPECT THAT ONE OF THE DISCHARGES MAY HAVE BEEN A LIGHTNING STRIKE.

Data retrieved from NASA's ASRS site as of August 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.