Air carrier flight crew deviated from a published STAR arrival course while coupled to aircraft flig...

Attributes
ACN	203625
Time
Date	199203
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : pye airport : sfo
State Reference	CA
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oak
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star enroute airway : oak
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : instrument pilot : commercial pilot : private
Experience	flight time last 90 days : 210 flight time total : 5000 flight time type : 1000
ASRS Report	203625
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : published procedure other anomaly other other spatial deviation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Flight guidance system was on VOR track, passing the pye VOR on the golden gate 2 arrival. The new radial outbound was set in the flight guidance system. Communications between us and ATC took place, checklists were run. During this period, the flight guidance system remained in crs. It took 14 NM before the flight guidance system went to capture and eventually VOR track. As a result, we flew by the VOR (pye) 14 NM before turning to the new outbound radial. Center advised us of the course deviation. We acknowledged and then proceeded direct to the sfo VOR. The large transport flight guidance system frequently takes 5-10 NM before capturing a new radial. Usually, it turns the opposite direction briefly before turning to the proper radial heading. One of the reasons flight guidance system were developed was to reduce 2 pilot crew workloads. This does not always seem to be the case.

Original NASA ASRS Text

Title: ACR FLC DEVIATED FROM A PUBLISHED STAR ARR COURSE WHILE COUPLED TO ACFT FLT GUIDANCE SYS.

Narrative: FLT GUIDANCE SYS WAS ON VOR TRACK, PASSING THE PYE VOR ON THE GOLDEN GATE 2 ARR. THE NEW RADIAL OUTBOUND WAS SET IN THE FLT GUIDANCE SYS. COMS BTWN US AND ATC TOOK PLACE, CHKLISTS WERE RUN. DURING THIS PERIOD, THE FLT GUIDANCE SYS REMAINED IN CRS. IT TOOK 14 NM BEFORE THE FLT GUIDANCE SYS WENT TO CAPTURE AND EVENTUALLY VOR TRACK. AS A RESULT, WE FLEW BY THE VOR (PYE) 14 NM BEFORE TURNING TO THE NEW OUTBOUND RADIAL. CTR ADVISED US OF THE COURSE DEV. WE ACKNOWLEDGED AND THEN PROCEEDED DIRECT TO THE SFO VOR. THE LGT FLT GUIDANCE SYS FREQUENTLY TAKES 5-10 NM BEFORE CAPTURING A NEW RADIAL. USUALLY, IT TURNS THE OPPOSITE DIRECTION BRIEFLY BEFORE TURNING TO THE PROPER RADIAL HDG. ONE OF THE REASONS FLT GUIDANCE SYS WERE DEVELOPED WAS TO REDUCE 2 PLT CREW WORKLOADS. THIS DOES NOT ALWAYS SEEM TO BE THE CASE.

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.

Air carrier flight crew deviated from a published STAR arrival course while coupled to aircraft flight guidance system.