Small aircraft on localizer DME approach has near midair collision with second small aircraft.

Attributes
ACN	314131
Time
Date	199508
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : hwd
State Reference	CA
Altitude	msl bound lower : 2600 msl bound upper : 2600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oak tower : pub
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	enroute other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 40 flight time total : 2750 flight time type : 600
ASRS Report	314131
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	conflict : airborne less severe
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 2500 vertical : 400
Supplementary
Primary Problem	Ambiguous

Narrative:

Cleared for localizer/DME runway 28L approach to hwd airport. ATC advised target 10-11 O'clock at 3000 ft sebound. Aircraft observed crossing localizer course (silver high-wing aircraft, possibly C150). Aircraft was headed directly toward me. I began steep descent on localizer course to avoid. Aircraft was within 1000 ft overhead before pilot began evasive action turn right, behind me. This is complex airspace. Aircraft may be talking with different facilities which are sometimes uncoordinated. Considering the altitude and direction of flight, I might guess that the other aircraft had just been released from oakland arsa airspace and was now proceeding VFR without advisories. This sets the stage for a conflict with aircraft inbound on the hwd localizer.

Original NASA ASRS Text

Title: SMA ON LOC DME APCH HAS NMAC WITH SECOND SMA.

Narrative: CLRED FOR LOC/DME RWY 28L APCH TO HWD ARPT. ATC ADVISED TARGET 10-11 O'CLOCK AT 3000 FT SEBOUND. ACFT OBSERVED XING LOC COURSE (SILVER HIGH-WING ACFT, POSSIBLY C150). ACFT WAS HEADED DIRECTLY TOWARD ME. I BEGAN STEEP DSCNT ON LOC COURSE TO AVOID. ACFT WAS WITHIN 1000 FT OVERHEAD BEFORE PLT BEGAN EVASIVE ACTION TURN R, BEHIND ME. THIS IS COMPLEX AIRSPACE. ACFT MAY BE TALKING WITH DIFFERENT FACILITIES WHICH ARE SOMETIMES UNCOORDINATED. CONSIDERING THE ALT AND DIRECTION OF FLT, I MIGHT GUESS THAT THE OTHER ACFT HAD JUST BEEN RELEASED FROM OAKLAND ARSA AIRSPACE AND WAS NOW PROCEEDING VFR WITHOUT ADVISORIES. THIS SETS THE STAGE FOR A CONFLICT WITH ACFT INBOUND ON THE HWD LOC.

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.