B737 crew is cleared direct to what they believe is tragg. Some time later ATC questions the crew on...

Attributes
ACN	988849
Time
Date	201201
Place
Locale Reference	ZAU.ARTCC
State Reference	IL
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Person 1
Function	First Officer
Experience	Flight Crew Last 90 Days 111 Flight Crew Type 237
Person 2
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 173 Flight Crew Type 6000
Events
Anomaly	Deviation - Procedural Clearance Deviation - Track / Heading All Types

Narrative:

We both verified the fix in the FMS before executing direct. While talking to chicago center around 45 minutes later; they asked what fix we had last been cleared to. I responded with tragg. He asked if we were direct to tragg; as he was showing us flying north of course. I confirmed we were direct to tragg and spelled the fix phonetically. He then replied with a clearance to trakk intersection. It seems the easiest way to avoid this situation is absolute diligence when reprogramming the FMC. The flight plan was eight or nine pages long; and it was easy to skip a page when looking for the correct waypoint. We both saw what we thought was the correct waypoint; and the pm verified with the PF before the change was executed. A quick glance at the paper release could have possibly revealed there were two very similar sounding waypoints on the flight plan.

Original NASA ASRS Text

Title: B737 crew is cleared direct to what they believe is TRAGG. Some time later ATC questions the crew on their navigation and it is discovered that they should be proceeding direct to TRAKK.

Narrative: We both verified the fix in the FMS before executing direct. While talking to Chicago Center around 45 minutes later; they asked what fix we had last been cleared to. I responded with TRAGG. He asked if we were direct to TRAGG; as he was showing us flying north of course. I confirmed we were direct to TRAGG and spelled the fix phonetically. He then replied with a clearance to TRAKK intersection. It seems the easiest way to avoid this situation is absolute diligence when reprogramming the FMC. The flight plan was eight or nine pages long; and it was easy to skip a page when looking for the correct waypoint. We both saw what we thought was the correct waypoint; and the PM verified with the PF before the change was executed. A quick glance at the paper release could have possibly revealed there were two very similar sounding waypoints on the flight plan.

Data retrieved from NASA's ASRS site as of July 2013 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.

B737 crew is cleared direct to what they believe is tragg. Some time later ATC questions the crew on their navigation and it is discovered that they should be proceeding direct to trakk.