Arriving DH8 crew responded to a descent RA from TCASII.

Attributes
ACN	495370
Time
Date	200012
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : phx.airport
State Reference	AZ
Altitude	msl bound lower : 9500 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zab.artcc tracon : p50.tracon
Operator	common carrier : air carrier
Make Model Name	Dash 8-200
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	descent : intermediate altitude
Route In Use	arrival star : blh.blh 3
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : p50.tracon
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise : level
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : cfi pilot : multi engine pilot : atp
Experience	flight time last 90 days : 100 flight time total : 5000 flight time type : 1000
ASRS Report	495370
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : multi engine
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : published procedure other anomaly other
Independent Detector	aircraft equipment : tcas
Resolutory Action	flight crew : took precautionary avoidance action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 500 vertical : 500
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance ATC Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While tracking inbound on the blyth arrival to phx (256 degree radial 40 NM phx) at 10000 ft MSL in the vicinity of arlin intersection, ZAB advised me of opposing traffic at 12 O'clock position, 10 mi and 500 ft above. The opposing traffic was not observed visually until within 1/2 NM. The traffic was observed on TCASII within 12 NM. When the traffic was within 6 NM and still not observed visually, I requested a descent to avoid a TCASII conflict. ZAB advised me to contact phx approach and make the request. In the process of frequency change, TCASII changed to RA and directed a descent. I complied and descended to 9500 ft MSL. Upon completing the frequency change and complying with TCASII, I reported the TCASII RA deviation to phx approach. Phx advised me that the other aircraft had had me in sight for 12 mi. An earlier descent or earlier frequency change would have prevented the deviation.

Original NASA ASRS Text

Title: ARRIVING DH8 CREW RESPONDED TO A DSCNT RA FROM TCASII.

Narrative: WHILE TRACKING INBOUND ON THE BLYTH ARR TO PHX (256 DEG RADIAL 40 NM PHX) AT 10000 FT MSL IN THE VICINITY OF ARLIN INTXN, ZAB ADVISED ME OF OPPOSING TFC AT 12 O'CLOCK POS, 10 MI AND 500 FT ABOVE. THE OPPOSING TFC WAS NOT OBSERVED VISUALLY UNTIL WITHIN 1/2 NM. THE TFC WAS OBSERVED ON TCASII WITHIN 12 NM. WHEN THE TFC WAS WITHIN 6 NM AND STILL NOT OBSERVED VISUALLY, I REQUESTED A DSCNT TO AVOID A TCASII CONFLICT. ZAB ADVISED ME TO CONTACT PHX APCH AND MAKE THE REQUEST. IN THE PROCESS OF FREQ CHANGE, TCASII CHANGED TO RA AND DIRECTED A DSCNT. I COMPLIED AND DSNDED TO 9500 FT MSL. UPON COMPLETING THE FREQ CHANGE AND COMPLYING WITH TCASII, I RPTED THE TCASII RA DEV TO PHX APCH. PHX ADVISED ME THAT THE OTHER ACFT HAD HAD ME IN SIGHT FOR 12 MI. AN EARLIER DSCNT OR EARLIER FREQ CHANGE WOULD HAVE PREVENTED THE DEV.

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.