MD80 crew has close encounter with king air on baret 4 arrival to san.

Attributes
ACN	709888
Time
Date	200609
Local Time Of Day	1201 To 1800
Place
Locale Reference	intersection : pillo
State Reference	CA
Altitude	msl single value : 16000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla.artcc
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Route In Use	arrival star : baret 4
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zla.artcc
Operator	general aviation : corporate
Make Model Name	King Air C90 E90
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	709888
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
ASRS Report	709889
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe
Independent Detector	aircraft equipment : tcas other flight crewa
Resolutory Action	controller : issued advisory flight crew : took evasive action
Miss Distance	vertical : 500
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance Airspace Structure
Primary Problem	Ambiguous

Narrative:

On baret 4 arrival into san; we descended to 16000 ft MSL. Our altimeter was set at san altimeter of 28.85. King air traffic was reported at 15000 ft MSL. Our TCAS showed him at 200 ft below us. Ultimately; an RA occurred directing us to climb (climbed to approximately 16500 ft MSL). The traffic looked closer than 500 ft below. Found out the king air was using the el centro altimeter of 29.63. With the altimeters that far apart; the altitudes flown were much closer than 500 ft. Advised ATC we were executing an RA maneuver. After we visually cleared the traffic; we descended back to 16000 ft.

Original NASA ASRS Text

Title: MD80 CREW HAS CLOSE ENCOUNTER WITH KING AIR ON BARET 4 ARR TO SAN.

Narrative: ON BARET 4 ARR INTO SAN; WE DSNDED TO 16000 FT MSL. OUR ALTIMETER WAS SET AT SAN ALTIMETER OF 28.85. KING AIR TFC WAS RPTED AT 15000 FT MSL. OUR TCAS SHOWED HIM AT 200 FT BELOW US. ULTIMATELY; AN RA OCCURRED DIRECTING US TO CLB (CLBED TO APPROX 16500 FT MSL). THE TFC LOOKED CLOSER THAN 500 FT BELOW. FOUND OUT THE KING AIR WAS USING THE EL CENTRO ALTIMETER OF 29.63. WITH THE ALTIMETERS THAT FAR APART; THE ALTS FLOWN WERE MUCH CLOSER THAN 500 FT. ADVISED ATC WE WERE EXECUTING AN RA MANEUVER. AFTER WE VISUALLY CLRED THE TFC; WE DSNDED BACK TO 16000 FT.

Data retrieved from NASA's ASRS site as of January 2009 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.