B737 flight crew appears not to have entered the required transition while flying the nobly RNAV SID...

Attributes
ACN	679793
Time
Date	200512
Local Time Of Day	1201 To 1800
Place
Locale Reference	intersection : cobug
State Reference	TX
Altitude	msl single value : 24000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw.artcc
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Navigation In Use	other Other
Flight Phase	climbout : intermediate altitude
Route In Use	departure sid : nobly
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
ASRS Report	679793
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	679798
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance controller : issued advisory
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

After departing dfw climbing through FL240 ATC reported that we were approximately 1.5 NM north of course. LNAV and autoplt were selected; aircraft appeared to be on course. ATC gave us 15 degree right turn and shortly thereafter gave us direct ortro. Wind 247/110 KTS. ATC then reported we appeared to be tracking direct centerline of course. On closer inspection we realized we were tracking direct lit instead of cobug.

Original NASA ASRS Text

Title: B737 FLT CREW APPEARS NOT TO HAVE ENTERED THE REQUIRED TRANSITION WHILE FLYING THE NOBLY RNAV SID FROM DFW.

Narrative: AFTER DEPARTING DFW CLBING THROUGH FL240 ATC REPORTED THAT WE WERE APPROX 1.5 NM N OF COURSE. LNAV AND AUTOPLT WERE SELECTED; ACFT APPEARED TO BE ON COURSE. ATC GAVE US 15 DEG R TURN AND SHORTLY THEREAFTER GAVE US DIRECT ORTRO. WIND 247/110 KTS. ATC THEN REPORTED WE APPEARED TO BE TRACKING DIRECT CTRLINE OF COURSE. ON CLOSER INSPECTION WE REALIZED WE WERE TRACKING DIRECT LIT INSTEAD OF COBUG.

Data retrieved from NASA's ASRS site as of January 2009 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 flight crew appears not to have entered the required transition while flying the nobly RNAV SID from dfw.