E170 reports FMS loss of transition waypoints on RNAV SID from dfw.

Attributes
ACN	694249
Time
Date	200604
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : dfw.airport
State Reference	TX
Altitude	msl single value : 12000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : d10.tracon
Operator	common carrier : air carrier
Make Model Name	EMB ERJ 170/175 ER&LR
Operating Under FAR Part	Part 121
Flight Phase	descent : holding
Route In Use	departure : other published ifr departure
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 240 flight time total : 6000 flight time type : 700
ASRS Report	694249
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	non adherence : clearance non adherence : published procedure other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued alert flight crew : returned to intended or assigned course
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Ambiguous
Air Traffic Incident	Pilot Deviation

Narrative:

During preflight planning the captain and I complied with both company and FAA directives concerning the usage of RNAV departures from dfw. The departure and transition point (as assigned by clearance) were correctly entered into the database and reviewed by both the captain and myself. Subsequent to departing dfw on this RNAV departure; ft worth center advised us that we were not on course to the anticipated intermediate waypoint. Upon review of the then resident FMS waypoints; it was discovered that at least two; and possibly three; waypoints had dropped out of the database. The captain and I immediately reentered the missing; and previously correctly entered; waypoints into the FMS and the aircraft returned to the ATC assigned course. Subsequent to arrival at lga; this FMS malfunction was reported to maintenance. The mechanic informed the captain and I that other aircraft had been written up for similar occurrences.

Original NASA ASRS Text

Title: E170 RPTS FMS LOSS OF TRANSITION WAYPOINTS ON RNAV SID FROM DFW.

Narrative: DURING PREFLT PLANNING THE CAPT AND I COMPLIED WITH BOTH COMPANY AND FAA DIRECTIVES CONCERNING THE USAGE OF RNAV DEPS FROM DFW. THE DEP AND TRANSITION POINT (AS ASSIGNED BY CLRNC) WERE CORRECTLY ENTERED INTO THE DATABASE AND REVIEWED BY BOTH THE CAPT AND MYSELF. SUBSEQUENT TO DEPARTING DFW ON THIS RNAV DEP; FT WORTH CTR ADVISED US THAT WE WERE NOT ON COURSE TO THE ANTICIPATED INTERMEDIATE WAYPOINT. UPON REVIEW OF THE THEN RESIDENT FMS WAYPOINTS; IT WAS DISCOVERED THAT AT LEAST TWO; AND POSSIBLY THREE; WAYPOINTS HAD DROPPED OUT OF THE DATABASE. THE CAPT AND I IMMEDIATELY REENTERED THE MISSING; AND PREVIOUSLY CORRECTLY ENTERED; WAYPOINTS INTO THE FMS AND THE ACFT RETURNED TO THE ATC ASSIGNED COURSE. SUBSEQUENT TO ARRIVAL AT LGA; THIS FMS MALFUNCTION WAS RPTED TO MAINT. THE MECHANIC INFORMED THE CAPT AND I THAT OTHER ACFT HAD BEEN WRITTEN UP FOR SIMILAR OCCURRENCES.

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.