CL65 crew had FMC navigation data drop out of the FMC.

Attributes
ACN	506605
Time
Date	200103
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : psp.vortac
State Reference	CA
Altitude	msl single value : 17000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla.artcc
Operator	common carrier : air carrier
Make Model Name	Regional Jet CL65, Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : vacating altitude
Route In Use	departure sid : psp4,twp
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 11000 flight time type : 4000
ASRS Report	506605
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : less severe non adherence : published procedure non adherence : clearance other anomaly other
Independent Detector	atc equipment other atc equipment : radar other controllera
Resolutory Action	controller : issued new clearance controller : issued alert flight crew : returned to intended or assigned course none taken : detected after the fact
Supplementary
Problem Areas	Aircraft FAA
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Our clearance was psp-slc via psp 4-TWP-jotnu as filed. I observed my first officer copy the clearance and program the fixes into the collins 4100 FMS. After takeoff we were passed from psp departure to ZLA. On contact with ZLA, the controller immediately ordered a right turn to 090 degrees and asked us how we were filed. We responded psp-twp as filed. At that point, I looked at the FMS and realized the FMS had dumped the twp-jotnu legs and was taking us direct to goffs. The controller stated we were about to enter hot restr airspace. 1 week later, departing slc for oma, once again the FMS dumped the slc-ocs leg. This time we caught it right away.

Original NASA ASRS Text

Title: CL65 CREW HAD FMC NAV DATA DROP OUT OF THE FMC.

Narrative: OUR CLRNC WAS PSP-SLC VIA PSP 4-TWP-JOTNU AS FILED. I OBSERVED MY FO COPY THE CLRNC AND PROGRAM THE FIXES INTO THE COLLINS 4100 FMS. AFTER TKOF WE WERE PASSED FROM PSP DEP TO ZLA. ON CONTACT WITH ZLA, THE CTLR IMMEDIATELY ORDERED A R TURN TO 090 DEGS AND ASKED US HOW WE WERE FILED. WE RESPONDED PSP-TWP AS FILED. AT THAT POINT, I LOOKED AT THE FMS AND REALIZED THE FMS HAD DUMPED THE TWP-JOTNU LEGS AND WAS TAKING US DIRECT TO GOFFS. THE CTLR STATED WE WERE ABOUT TO ENTER HOT RESTR AIRSPACE. 1 WK LATER, DEPARTING SLC FOR OMA, ONCE AGAIN THE FMS DUMPED THE SLC-OCS LEG. THIS TIME WE CAUGHT IT RIGHT AWAY.

Data retrieved from NASA's ASRS site as of July 2007 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.