B737-800 FMS fails to provide proper LNAV guidance on san jose SID.

Attributes
ACN	782582
Time
Date	200804
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sjc.airport
State Reference	CA
Altitude	msl single value : 5000
Aircraft 1
Controlling Facilities	tracon : nct.tracon
Operator	common carrier : air carrier
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Route In Use	departure sid : sjc
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	782582
Events
Anomaly	aircraft equipment problem : less severe other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	aircraft : equipment problem dissipated flight crew : overrode automation
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

We were cleared for the sjc SID. LNAV was selected during taxi out to the runway. Annunciations were normal. During initial climb; LNAV provided what appeared to be normal guidance and we tracked the magenta line using the flight director. However; when we reached the first fix; LNAV did not command a turn to the sbound heading and the aircraft had to be maneuvered to that heading. Subsequent guidance appeared normal and LNAV commanded an intercept and tracking of the outbound radial. All other operation was normal.

Original NASA ASRS Text

Title: B737-800 FMS FAILS TO PROVIDE PROPER LNAV GUIDANCE ON SAN JOSE SID.

Narrative: WE WERE CLRED FOR THE SJC SID. LNAV WAS SELECTED DURING TAXI OUT TO THE RWY. ANNUNCIATIONS WERE NORMAL. DURING INITIAL CLB; LNAV PROVIDED WHAT APPEARED TO BE NORMAL GUIDANCE AND WE TRACKED THE MAGENTA LINE USING THE FLT DIRECTOR. HOWEVER; WHEN WE REACHED THE FIRST FIX; LNAV DID NOT COMMAND A TURN TO THE SBOUND HDG AND THE ACFT HAD TO BE MANEUVERED TO THAT HDG. SUBSEQUENT GUIDANCE APPEARED NORMAL AND LNAV COMMANDED AN INTERCEPT AND TRACKING OF THE OUTBOUND RADIAL. ALL OTHER OP WAS NORMAL.

Data retrieved from NASA's ASRS site as of May 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.