Altitude deviation, air carrier reversed its descent to avoid a VFR aircraft.

Attributes
ACN	317640
Time
Date	199510
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : slc
State Reference	UT
Altitude	msl bound lower : 11000 msl bound upper : 11500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : slc
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise other descent other
Flight Plan	IFR
Aircraft 2
Make Model Name	PA-28 Cherokee/Archer II/Dakota/Pillan/Warrior
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 180 flight time total : 6900 flight time type : 4900
ASRS Report	317640
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	317636
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	flight crew : took evasive action other
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 30000 vertical : 1000
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While descending from 12000 ft to 9000 ft MSL, we were given traffic at 1-2 O'clock eastbound at 10500 ft (we were sbound). We did not have him visually and leveled at 11000 ft as TCASII showed constant bearing and decreasing range. Approach told us we could remain there (delay our descent to 9000 ft) until we were clear of traffic. Since we did not have him visually, we climbed to 11500 ft (1000 ft separation). As TCASII called 'traffic, traffic,' we made visual contact and descended to 9000 ft.

Original NASA ASRS Text

Title: ALTDEV, ACR REVERSED ITS DSCNT TO AVOID A VFR ACFT.

Narrative: WHILE DSNDING FROM 12000 FT TO 9000 FT MSL, WE WERE GIVEN TFC AT 1-2 O'CLOCK EBOUND AT 10500 FT (WE WERE SBOUND). WE DID NOT HAVE HIM VISUALLY AND LEVELED AT 11000 FT AS TCASII SHOWED CONSTANT BEARING AND DECREASING RANGE. APCH TOLD US WE COULD REMAIN THERE (DELAY OUR DSCNT TO 9000 FT) UNTIL WE WERE CLR OF TFC. SINCE WE DID NOT HAVE HIM VISUALLY, WE CLBED TO 11500 FT (1000 FT SEPARATION). AS TCASII CALLED 'TFC, TFC,' WE MADE VISUAL CONTACT AND DSNDED TO 9000 FT.

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.