A320 loses FMC route on civet STAR to lax when late runway change is programmed.

Attributes
ACN	751205
Time
Date	200708
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : lax.airport
State Reference	CA
Altitude	msl single value : 19000
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : intermediate altitude
Route In Use	arrival star : civet
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 200 flight time total : 8800 flight time type : 600
ASRS Report	751205
Events
Anomaly	non adherence : published procedure non adherence : clearance other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : returned to intended or assigned course
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	Ambiguous

Narrative:

About 4 mi to gramm given civet to runway 24R. When runway 24R was selected; the civet RNAV route disappeared from the navigation display. This occurs on the A320 with specific runway arrs when the runway is changed without reselecting the prior arrival. While manually tuning the arrival; socal directed us to start the descent; approaching civet and turning inbound to lax; socal asked us to descend further. At this point we informed ATC that the route had dropped out of our flight plan. Socal offered vectors to ILS runway 24R and the rest of the approach was uneventful. Lesson learned: 1) should have asked for ATC vectors as soon as the civet arrival had disappeared; instead of trying to play catch-up. 2) having the runway 24R runway preloaded into the secondary flight plan would have made the recovery easier.

Original NASA ASRS Text

Title: A320 LOSES FMC ROUTE ON CIVET STAR TO LAX WHEN LATE RWY CHANGE IS PROGRAMMED.

Narrative: ABOUT 4 MI TO GRAMM GIVEN CIVET TO RWY 24R. WHEN RWY 24R WAS SELECTED; THE CIVET RNAV RTE DISAPPEARED FROM THE NAV DISPLAY. THIS OCCURS ON THE A320 WITH SPECIFIC RWY ARRS WHEN THE RWY IS CHANGED WITHOUT RESELECTING THE PRIOR ARR. WHILE MANUALLY TUNING THE ARR; SOCAL DIRECTED US TO START THE DSCNT; APCHING CIVET AND TURNING INBOUND TO LAX; SOCAL ASKED US TO DSND FURTHER. AT THIS POINT WE INFORMED ATC THAT THE RTE HAD DROPPED OUT OF OUR FLT PLAN. SOCAL OFFERED VECTORS TO ILS RWY 24R AND THE REST OF THE APCH WAS UNEVENTFUL. LESSON LEARNED: 1) SHOULD HAVE ASKED FOR ATC VECTORS AS SOON AS THE CIVET ARR HAD DISAPPEARED; INSTEAD OF TRYING TO PLAY CATCH-UP. 2) HAVING THE RWY 24R RWY PRELOADED INTO THE SECONDARY FLT PLAN WOULD HAVE MADE THE RECOVERY EASIER.

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.