B727 flight crew climb in response to a TCASII RA showing an aircraft 400 ft below during a STAR arr...

Attributes
ACN	542120
Time
Date	200203
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : sck.tracon
State Reference	CA
Altitude	msl single value : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sck.tracon tower : sdm.tower
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach descent : intermediate altitude
Route In Use	arrival : on vectors arrival star : marvin one
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zoa.artcc tracon : sck.tracon
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 16000 flight time type : 4000
ASRS Report	542120
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	conflict : nmac non adherence : far non adherence : required legal separation other anomaly other
Independent Detector	aircraft equipment : tcas other flight crewa other flight crewb
Resolutory Action	flight crew : took precautionary avoidance action flight crew : took evasive action flight crew : returned to original clearance flight crew : returned to assigned altitude
Consequence	faa : reviewed incident with flight crew
Miss Distance	vertical : 400
Supplementary
Problem Areas	ATC Facility Flight Crew Human Performance Airspace Structure ATC Human Performance Aircraft
Primary Problem	ATC Facility

Narrative:

We were on a vector with stockton approach while on the marvn one arrival to oakland. We had just been cleared to 8000 ft from 10000 ft. Just prior to beginning our descent we received a TCASII alert 'traffic, traffic.' we maintained 10000 ft and observed a yellow traffic symbol at 12 O'clock position and 2 mi 400 ft below us. Almost immediately we received a TCASII RA, 'climb, climb, climb.' we executed an immediate climb and at 10800 ft the warning changed to 'monitor vertical speed' then 'clear of conflict.' we advised stockton of our advisory while climbing and reported level at 11000 ft then clear of traffic and returning to 10000 ft. We verified that we were still cleared to 8000 ft and continued our approach without incident. The TCASII saved what might have been a very close call at best or a midair collision at worst. We never saw the traffic nor did the controller, so we assume it was VFR.

Original NASA ASRS Text

Title: B727 FLC CLB IN RESPONSE TO A TCASII RA SHOWING AN ACFT 400 FT BELOW DURING A STAR ARR AT 10000 FT.

Narrative: WE WERE ON A VECTOR WITH STOCKTON APCH WHILE ON THE MARVN ONE ARR TO OAKLAND. WE HAD JUST BEEN CLRED TO 8000 FT FROM 10000 FT. JUST PRIOR TO BEGINNING OUR DSCNT WE RECEIVED A TCASII ALERT 'TFC, TFC.' WE MAINTAINED 10000 FT AND OBSERVED A YELLOW TFC SYMBOL AT 12 O'CLOCK POS AND 2 MI 400 FT BELOW US. ALMOST IMMEDIATELY WE RECEIVED A TCASII RA, 'CLB, CLB, CLB.' WE EXECUTED AN IMMEDIATE CLB AND AT 10800 FT THE WARNING CHANGED TO 'MONITOR VERT SPD' THEN 'CLR OF CONFLICT.' WE ADVISED STOCKTON OF OUR ADVISORY WHILE CLBING AND RPTED LEVEL AT 11000 FT THEN CLR OF TFC AND RETURNING TO 10000 FT. WE VERIFIED THAT WE WERE STILL CLRED TO 8000 FT AND CONTINUED OUR APCH WITHOUT INCIDENT. THE TCASII SAVED WHAT MIGHT HAVE BEEN A VERY CLOSE CALL AT BEST OR A MIDAIR COLLISION AT WORST. WE NEVER SAW THE TFC NOR DID THE CTLR, SO WE ASSUME IT WAS VFR.

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.

B727 flight crew climb in response to a TCASII RA showing an aircraft 400 ft below during a STAR arrival at 10000 ft.