A B737-800 proceeds to ssm instead of flying towards buf on J95 like the flight plan says to do.

Attributes
ACN	418060
Time
Date	199810
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : cfb
State Reference	NY
Altitude	msl bound lower : 31000 msl bound upper : 31000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zob
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : direct enroute airway : j95
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 120 flight time total : 13800 flight time type : 1000
ASRS Report	418060
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : clearance non adherence other other spatial deviation
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Routing on pre departure clearance for flight ewr-sea showed ewr 6 departure to gayel, J95 buf, ssm. I, as first officer, checked the route twice in the FMC and it was the same as the pre departure clearance. After departure, we flew the route on J95 to cfb and the aircraft proceeded direct to ssm omitting buf. About 20 mi out of cfb ZOB asked us our routing. We noticed the discrepancy and told him we would proceed to buf, which we did. The only thing that we thought could have happened since neither of us deleted buf in the FMC is that we inadvertently downloaded a second flight plan into the FMC after I checked the first downloaded flight plan and the possibly second downloaded flight plan had cfb direct ssm.

Original NASA ASRS Text

Title: A B737-800 PROCEEDS TO SSM INSTEAD OF FLYING TOWARDS BUF ON J95 LIKE THE FLT PLAN SAYS TO DO.

Narrative: ROUTING ON PDC FOR FLT EWR-SEA SHOWED EWR 6 DEP TO GAYEL, J95 BUF, SSM. I, AS FO, CHKED THE RTE TWICE IN THE FMC AND IT WAS THE SAME AS THE PDC. AFTER DEP, WE FLEW THE RTE ON J95 TO CFB AND THE ACFT PROCEEDED DIRECT TO SSM OMITTING BUF. ABOUT 20 MI OUT OF CFB ZOB ASKED US OUR ROUTING. WE NOTICED THE DISCREPANCY AND TOLD HIM WE WOULD PROCEED TO BUF, WHICH WE DID. THE ONLY THING THAT WE THOUGHT COULD HAVE HAPPENED SINCE NEITHER OF US DELETED BUF IN THE FMC IS THAT WE INADVERTENTLY DOWNLOADED A SECOND FLT PLAN INTO THE FMC AFTER I CHKED THE FIRST DOWNLOADED FLT PLAN AND THE POSSIBLY SECOND DOWNLOADED FLT PLAN HAD CFB DIRECT SSM.

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.