An A320 flight crew initiate a descent early resulting in a TCASII RA.

Attributes
ACN	620214
Time
Date	200407
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : bur.airport
State Reference	CA
Altitude	msl single value : 2800
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	tower : bur.tower
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : sct.tracon
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 260 flight time total : 8200 flight time type : 4000
ASRS Report	620214
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne critical non adherence : far non adherence : clearance
Independent Detector	aircraft equipment : tcas
Miss Distance	horizontal : 9000 vertical : 400
Supplementary
Problem Areas	Environmental Factor Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On visual approach with landing clearance, approach issued 'at or above 3000 ft until established on final.' began turn to final runway 15 earlier than normal to avoid terrain to the east. Also initiated descent during turn causing RA from TCASII. Complied with RA and continued turn to south away from traffic and terrain to the north. Returned to land VFR on runway 8. Fatigue was a factor in poor decision to begin descent to landing prior to being fully established on final. Also poor light due to dusk lead to apprehension with terrain avoidance. Remaining with approach control longer would have facilitated better traffic and terrain avoidance.

Original NASA ASRS Text

Title: AN A320 FLT CREW INITIATE A DSCNT EARLY RESULTING IN A TCASII RA.

Narrative: ON VISUAL APCH WITH LNDG CLRNC, APCH ISSUED 'AT OR ABOVE 3000 FT UNTIL ESTABLISHED ON FINAL.' BEGAN TURN TO FINAL RWY 15 EARLIER THAN NORMAL TO AVOID TERRAIN TO THE E. ALSO INITIATED DSCNT DURING TURN CAUSING RA FROM TCASII. COMPLIED WITH RA AND CONTINUED TURN TO S AWAY FROM TFC AND TERRAIN TO THE N. RETURNED TO LAND VFR ON RWY 8. FATIGUE WAS A FACTOR IN POOR DECISION TO BEGIN DSCNT TO LNDG PRIOR TO BEING FULLY ESTABLISHED ON FINAL. ALSO POOR LIGHT DUE TO DUSK LEAD TO APPREHENSION WITH TERRAIN AVOIDANCE. REMAINING WITH APCH CTL LONGER WOULD HAVE FACILITATED BETTER TFC AND TERRAIN AVOIDANCE.

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.