B737-300 first officer reports entering swz instead of szw resulting in a track deviation. The entry...

Narrative:

Taxiing out in bna; we were given an ATC reroute for our flight. Our new route was to fly the tippn 1 to brxtn then szw... When I loaded the route; I loaded swz instead of szw. When we crossed brxtn; the plane began to turn left. We immediately recognized the beginning of a problem; selected heading; and started turning south. We asked memphis center for a vector toward seminole [szw]. The controller told us to fly 180 degrees. He then told us to fly 160 degrees and proceed direct to seminole when able. He then asked the reason for the navigation issue. We were not sure at that time; but quickly realized that swz had been loaded instead of szw. Both crew members should confirm reroute entries. While we both knew what was being input; I should have confirmed the route distance with the captain. We were in a -300 so did not have a magenta line to notice the error. A magenta line would have been a sure indicator of a route problem.

Original NASA ASRS Text

Title: B737-300 First Officer reports entering SWZ instead of SZW resulting in a track deviation. The entry was part of a reroute clearance that was entered during taxi and not checked.

Narrative: Taxiing out in BNA; we were given an ATC reroute for our flight. Our new route was to fly the TIPPN 1 to BRXTN then SZW... When I loaded the route; I loaded SWZ instead of SZW. When we crossed BRXTN; the plane began to turn left. We immediately recognized the beginning of a problem; selected heading; and started turning south. We asked Memphis Center for a vector toward SEMINOLE [SZW]. The Controller told us to fly 180 degrees. He then told us to fly 160 degrees and proceed direct to SEMINOLE when able. He then asked the reason for the navigation issue. We were not sure at that time; but quickly realized that SWZ had been loaded instead of SZW. Both crew members should confirm reroute entries. While we both knew what was being input; I should have confirmed the route distance with the Captain. We were in a -300 so did not have a magenta line to notice the error. A magenta line would have been a sure indicator of a route problem.

Data retrieved from NASA's ASRS site 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.

Attributes
ACN	1166385
Time
Date	201404
Local Time Of Day	1801-2400
Place
Locale Reference	ZME.ARTCC
State Reference	TN
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	Climb
Component
Aircraft Component	FMS/FMC
Person 1
Function	First Officer
Experience	Flight Crew Last 90 Days 92
Events
Anomaly	Deviation - Procedural Clearance Deviation - Track / Heading All Types

B737-300 first officer reports entering swz instead of szw resulting in a track deviation. The entry was part of a reroute clearance that was entered during taxi and not checked.