MD80 on RNAV SID from dfw experiences loss of transition waypoint in FMS route.

Attributes
ACN	673119
Time
Date	200509
Local Time Of Day	0601 To 1200
Place
Locale Reference	intersection : akuna
State Reference	TX
Altitude	msl single value : 20000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : d10.tracon
Operator	common carrier : air carrier
Make Model Name	MD-83
Operating Under FAR Part	Part 121
Navigation In Use	other Other
Flight Phase	climbout : initial
Route In Use	departure sid : akuna
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	673119
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure other spatial deviation
Independent Detector	other flight crewa
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

After loading and verifying all points in the FMS for the akuna RNAV departure we verified that mlc was in the box and then rzc. Upon reaching akuna intersection the FMS dropped mlc intersection and aircraft FMS had us going to rzc instead of mlc then rzc. No conflict with ATC; however it was not normal for a fix to drop out after we verified it prior to departure and at the gate. Will make sure the next filed waypoint is in the box prior to the turn next time.

Original NASA ASRS Text

Title: MD80 ON RNAV SID FROM DFW EXPERIENCES LOSS OF TRANSITION WAYPOINT IN FMS RTE.

Narrative: AFTER LOADING AND VERIFYING ALL POINTS IN THE FMS FOR THE AKUNA RNAV DEP WE VERIFIED THAT MLC WAS IN THE BOX AND THEN RZC. UPON REACHING AKUNA INTERSECTION THE FMS DROPPED MLC INTERSECTION AND ACFT FMS HAD US GOING TO RZC INSTEAD OF MLC THEN RZC. NO CONFLICT WITH ATC; HOWEVER IT WAS NOT NORMAL FOR A FIX TO DROP OUT AFTER WE VERIFIED IT PRIOR TO DEP AND AT THE GATE. WILL MAKE SURE THE NEXT FILED WAYPOINT IS IN THE BOX PRIOR TO THE TURN NEXT TIME.

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.