Commuter flight crew of EMB120 has near midair collision with be-136 on descent.

Attributes
ACN	363611
Time
Date	199703
Day	Tue
Place
Locale Reference	atc facility : pdz
State Reference	CA
Altitude	msl bound lower : 9600 msl bound upper : 9600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ont tower : gvw
Operator	common carrier : air carrier
Make Model Name	Brasilia EMB-120 All Series
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	descent other
Flight Plan	IFR
Aircraft 2
Make Model Name	Bonanza 36
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 11000 flight time type : 2300
ASRS Report	363611
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : nmac
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 200 vertical : 100
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

We were cleared to descend from 10000 ft to 8000 ft. (En route from psp to lax.) passing through 9700 ft, first officer (PNF) saw a TCASII target pop-up. First officer selected 5 mi range on TCASII and target disappeared, then came back indicating 12 O'clock and 300 ft below us at 3 mi. I disengaged the autoplt and slowed our rate of descent while scanning for the traffic. When I could not acquire the traffic visually and the TCASII showed it at 12 O'clock, less than 1 mi, 100 ft below I pitched the aircraft nose up, initiating a climb. At this point I saw the traffic passing below, approximately 200 ft off the left wingtip. ATC had acquired the target at virtually the same time as we did. The controller speculated that the other pilot saw us and then turned on his transponder. If that is the case then this near miss might have been avoided had the pilot turned on his transponder on takeoff. Callback conversation with reporter revealed the following information: reporter states that in a conversation with a supervisor at approach he learned that ATC was tracking the aircraft but lost him when he went through the banning pass. There has been no further action. Reporter was on V388 airway and on an IFR flight plan.

Original NASA ASRS Text

Title: COMMUTER FLC OF EMB120 HAS NMAC WITH BE-136 ON DSCNT.

Narrative: WE WERE CLRED TO DSND FROM 10000 FT TO 8000 FT. (ENRTE FROM PSP TO LAX.) PASSING THROUGH 9700 FT, FO (PNF) SAW A TCASII TARGET POP-UP. FO SELECTED 5 MI RANGE ON TCASII AND TARGET DISAPPEARED, THEN CAME BACK INDICATING 12 O'CLOCK AND 300 FT BELOW US AT 3 MI. I DISENGAGED THE AUTOPLT AND SLOWED OUR RATE OF DSCNT WHILE SCANNING FOR THE TFC. WHEN I COULD NOT ACQUIRE THE TFC VISUALLY AND THE TCASII SHOWED IT AT 12 O'CLOCK, LESS THAN 1 MI, 100 FT BELOW I PITCHED THE ACFT NOSE UP, INITIATING A CLB. AT THIS POINT I SAW THE TFC PASSING BELOW, APPROX 200 FT OFF THE L WINGTIP. ATC HAD ACQUIRED THE TARGET AT VIRTUALLY THE SAME TIME AS WE DID. THE CTLR SPECULATED THAT THE OTHER PLT SAW US AND THEN TURNED ON HIS XPONDER. IF THAT IS THE CASE THEN THIS NEAR MISS MIGHT HAVE BEEN AVOIDED HAD THE PLT TURNED ON HIS XPONDER ON TKOF. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT IN A CONVERSATION WITH A SUPVR AT APCH HE LEARNED THAT ATC WAS TRACKING THE ACFT BUT LOST HIM WHEN HE WENT THROUGH THE BANNING PASS. THERE HAS BEEN NO FURTHER ACTION. RPTR WAS ON V388 AIRWAY AND ON AN IFR FLT PLAN.

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.