E145 flight crew deviated from RNAV SID track at dfw when FMS systems unable to deal with crosswind.

Attributes
ACN	678946
Time
Date	200511
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : dfw.airport
State Reference	TX
Altitude	msl single value : 1200
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : d10.tracon
Operator	common carrier : air carrier
Make Model Name	EMB ERJ 145 ER&LR
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : initial
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial
Experience	flight time last 90 days : 200 flight time total : 20000 flight time type : 2400
ASRS Report	678946
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical non adherence : clearance non adherence : published procedure other spatial deviation
Independent Detector	other controllera
Resolutory Action	aircraft : equipment problem dissipated controller : issued new clearance
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Aircraft

Narrative:

RNAV departure at night off runway 36R at dfw. After departure at approximately 1200 ft MSL using the FMS; command bars are indicating a right turn with approximate 5 degrees of bank. Following the command bars keeps the CDI perfectly centered. I checked the wind to see why a right turn was being displayed. FMS showed 42 KTS of crosswind from the 2 O'clock position. We continued to follow command bars with CDI perfectly centered. ATC queried whether we show ourselves on course. I replied affirmative. ATC replied; 'I show you right of course; turn left to heading 330.' first officer was the PF who complied with ATC's instructions. As we made the left turn; the CDI corrected back to the left and the wind speed and direction indicated on the mfd was 7 KTS from our 2 O'clock position. From the cockpit instruments the maximum deviation was 1/2 to 1 DOT right of course and that occurred only after we began our turn to the ATC heading of 330 degrees. The remainder of the flight was uneventful and provided no indication of instrument error during the remainder of the flight. The FMS was properly programmed with no abnormal/error messages displayed.

Original NASA ASRS Text

Title: E145 FLT CREW DEVIATED FROM RNAV SID TRACK AT DFW WHEN FMS SYSTEMS UNABLE TO DEAL WITH XWIND.

Narrative: RNAV DEP AT NIGHT OFF RWY 36R AT DFW. AFTER DEP AT APPROX 1200 FT MSL USING THE FMS; COMMAND BARS ARE INDICATING A R TURN WITH APPROXIMATE 5 DEGS OF BANK. FOLLOWING THE COMMAND BARS KEEPS THE CDI PERFECTLY CENTERED. I CHKED THE WIND TO SEE WHY A R TURN WAS BEING DISPLAYED. FMS SHOWED 42 KTS OF XWIND FROM THE 2 O'CLOCK POSITION. WE CONTINUED TO FOLLOW COMMAND BARS WITH CDI PERFECTLY CENTERED. ATC QUERIED WHETHER WE SHOW OURSELVES ON COURSE. I REPLIED AFFIRMATIVE. ATC REPLIED; 'I SHOW YOU R OF COURSE; TURN L TO HDG 330.' FO WAS THE PF WHO COMPLIED WITH ATC'S INSTRUCTIONS. AS WE MADE THE L TURN; THE CDI CORRECTED BACK TO THE L AND THE WIND SPD AND DIRECTION INDICATED ON THE MFD WAS 7 KTS FROM OUR 2 O'CLOCK POSITION. FROM THE COCKPIT INSTRUMENTS THE MAXIMUM DEVIATION WAS 1/2 TO 1 DOT RIGHT OF COURSE AND THAT OCCURRED ONLY AFTER WE BEGAN OUR TURN TO THE ATC HDG OF 330 DEGS. THE REMAINDER OF THE FLT WAS UNEVENTFUL AND PROVIDED NO INDICATION OF INSTRUMENT ERROR DURING THE REMAINDER OF THE FLT. THE FMS WAS PROPERLY PROGRAMMED WITH NO ABNORMAL/ERROR MESSAGES DISPLAYED.

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.