At light transport and an small aircraft had an near midair collision.

Attributes
ACN	240368
Time
Date	199305
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : psp
State Reference	CA
Altitude	agl bound lower : 3000 agl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : psp tower : psp
Operator	general aviation : corporate
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach descent other
Route In Use	approach : visual
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft, Low Wing, 2 Eng, Retractable Gear
Flight Phase	descent : approach
Route In Use	approach : visual
Person 1
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 40 flight time total : 2800 flight time type : 1000
ASRS Report	240368
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : nmac
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : took evasive action other
Consequence	Other
Miss Distance	horizontal : 300 vertical : 100
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

We arrived into the psp area from our departure airport (lax). Had descended over the mountains making our base leg to runway 31L at psp. We had just switched from approach to tower. Advised tower we were on left base leg for 31L. They instructed us to immediately turn left and level off due to a twin small aircraft in our 12 O'clock position. As the traffic was called, I saw the traffic and yelled to the captain to turn hard left. At that point he saw the traffic and continued the hard left turn and dropped the nose down to avert the collision. At that point we were approximately 7 mi to the left of 31L centerline. The twin small aircraft banked to the right and climbed. I believe our paths crossed -- the twin small aircraft above us and us below the small aircraft. I believe that if the tower had not advised us we would have collided with the twin small aircraft. Factors in this situation: I feel that, with our very steep descent on base leg over the high terrain, we could not see the small aircraft in our nose low attitude. Also, approach never advised us of the traffic lining up for the same runway as well as we were just being handed off to the tower. This incident sure has me looking out the window a lot more now.

Original NASA ASRS Text

Title: AT LTT AND AN SMA HAD AN NMAC.

Narrative: WE ARRIVED INTO THE PSP AREA FROM OUR DEP ARPT (LAX). HAD DSNDED OVER THE MOUNTAINS MAKING OUR BASE LEG TO RWY 31L AT PSP. WE HAD JUST SWITCHED FROM APCH TO TWR. ADVISED TWR WE WERE ON L BASE LEG FOR 31L. THEY INSTRUCTED US TO IMMEDIATELY TURN L AND LEVEL OFF DUE TO A TWIN SMA IN OUR 12 O'CLOCK POS. AS THE TFC WAS CALLED, I SAW THE TFC AND YELLED TO THE CAPT TO TURN HARD L. AT THAT POINT HE SAW THE TFC AND CONTINUED THE HARD L TURN AND DROPPED THE NOSE DOWN TO AVERT THE COLLISION. AT THAT POINT WE WERE APPROX 7 MI TO THE L OF 31L CTRLINE. THE TWIN SMA BANKED TO THE R AND CLBED. I BELIEVE OUR PATHS CROSSED -- THE TWIN SMA ABOVE US AND US BELOW THE SMA. I BELIEVE THAT IF THE TWR HAD NOT ADVISED US WE WOULD HAVE COLLIDED WITH THE TWIN SMA. FACTORS IN THIS SIT: I FEEL THAT, WITH OUR VERY STEEP DSCNT ON BASE LEG OVER THE HIGH TERRAIN, WE COULD NOT SEE THE SMA IN OUR NOSE LOW ATTITUDE. ALSO, APCH NEVER ADVISED US OF THE TFC LINING UP FOR THE SAME RWY AS WELL AS WE WERE JUST BEING HANDED OFF TO THE TWR. THIS INCIDENT SURE HAS ME LOOKING OUT THE WINDOW A LOT MORE NOW.

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.