Close proximity two GA small aircraft aircraft converging on rhv for landing.

Attributes
ACN	84852
Time
Date	198804
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : rhv
State Reference	CA
Altitude	msl bound lower : 1600 msl bound upper : 1800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : rhv
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other descent other
Flight Plan	None
Aircraft 2
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Experience	flight time last 90 days : 13 flight time total : 1700 flight time type : 1500
ASRS Report	84852
Person 2
Function	controller : local
Qualification	controller : radar
Events
Anomaly	conflict : nmac
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 300 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

Approaching rhv, approximately 10 mile north. I called the tower; was given a squawk code and a report of small aircraft X traffic also inbound. As I descended thru 1700' I was told there was an small aircraft X at 12 O'clock altitude unknown. I reported, 'no contact'. The tower then asked the small aircraft X for altitude, to which the small aircraft X responded '1600''. I stopped my descent, climbed back to 1800, and turned left 20 degree. Approximately a minute later the tower reported the small aircraft X was on my right. I responded, 'no contact'. Shortly the small aircraft X reported that I had passed within 300'. At no time did I see the small aircraft X. No suggestions to prevent a recurrence other then to observe that see-and-avoid is inadequate. Radar and an altitude reporting transponder are essential.

Original NASA ASRS Text

Title: CLOSE PROX TWO GA SMA ACFT CONVERGING ON RHV FOR LNDG.

Narrative: APCHING RHV, APPROX 10 MILE NORTH. I CALLED THE TWR; WAS GIVEN A SQUAWK CODE AND A REPORT OF SMA X TFC ALSO INBOUND. AS I DESCENDED THRU 1700' I WAS TOLD THERE WAS AN SMA X AT 12 O'CLOCK ALT UNKNOWN. I REPORTED, 'NO CONTACT'. THE TWR THEN ASKED THE SMA X FOR ALT, TO WHICH THE SMA X RESPONDED '1600''. I STOPPED MY DESCENT, CLIMBED BACK TO 1800, AND TURNED LEFT 20 DEG. APPROX A MINUTE LATER THE TWR REPORTED THE SMA X WAS ON MY RIGHT. I RESPONDED, 'NO CONTACT'. SHORTLY THE SMA X REPORTED THAT I HAD PASSED WITHIN 300'. AT NO TIME DID I SEE THE SMA X. NO SUGGESTIONS TO PREVENT A RECURRENCE OTHER THEN TO OBSERVE THAT SEE-AND-AVOID IS INADEQUATE. RADAR AND AN ALT REPORTING TRANSPONDER ARE ESSENTIAL.

Data retrieved from NASA's ASRS site as of August 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.