GA pilot misses OM call to tower and incurs an near midair collision with another GA on 1 mi final.

Attributes
ACN	529950
Time
Date	200111
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dtn.airport
State Reference	LA
Altitude	agl single value : 500
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : shv.tracon tower : dtn.tower
Operator	general aviation : personal
Make Model Name	Cardinal 177/177RG
Operating Under FAR Part	Part 91
Navigation In Use	ils localizer only : 14
Flight Phase	descent : approach
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : dtn.tower
Operator	general aviation : personal
Make Model Name	Cessna Single Piston Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Experience	flight time last 90 days : 30 flight time total : 1110 flight time type : 500
ASRS Report	529950
Person 2
Affiliation	other
Function	flight crew : single pilot
Events
Anomaly	airspace violation : entry conflict : nmac inflight encounter : weather non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	faa : investigated faa : reviewed incident with flight crew
Miss Distance	horizontal : 100 vertical : 0
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance Weather
Primary Problem	Flight Crew Human Performance

Narrative:

Had received radar vector from shv approach to intercept localizer for localizer runway 14 into dtn (shreveport downtown). At intercept, approach directed to call tower, no mention made of cancellation of radar services and squawk not changed. Tower cleared to land and instructed me to call the OM. I was still in IFR conditions at time of call. Continued approach, but failed to call the OM. At 1.8 DME, I looked for the runway and saw C172 approximately 100 ft off left wing. Made immediate right 360 degrees. The C172 had an instructor onboard, and I had monitored xmissions that made me believe it was not at airport, but was setting up for an approach. On ground, I called tower to discuss and acknowledged failure to call OM, and learned that they do not have radar at their tower. Dtn sits under the shv-bad class C, and I never received any indication that radar separation was being discontinued. Corrective action: more attention to communication procedures to call OM (for me). For other aircraft: CFI ought to be looking outside of cockpit (they never saw me). Tower: needs radar. Approach: when handling traffic in IMC needs to clarify/emphasize cancellation of radar services.

Original NASA ASRS Text

Title: GA PLT MISSES OM CALL TO TWR AND INCURS AN NMAC WITH ANOTHER GA ON 1 MI FINAL.

Narrative: HAD RECEIVED RADAR VECTOR FROM SHV APCH TO INTERCEPT LOC FOR LOC RWY 14 INTO DTN (SHREVEPORT DOWNTOWN). AT INTERCEPT, APCH DIRECTED TO CALL TWR, NO MENTION MADE OF CANCELLATION OF RADAR SVCS AND SQUAWK NOT CHANGED. TWR CLRED TO LAND AND INSTRUCTED ME TO CALL THE OM. I WAS STILL IN IFR CONDITIONS AT TIME OF CALL. CONTINUED APCH, BUT FAILED TO CALL THE OM. AT 1.8 DME, I LOOKED FOR THE RWY AND SAW C172 APPROX 100 FT OFF L WING. MADE IMMEDIATE R 360 DEGS. THE C172 HAD AN INSTRUCTOR ONBOARD, AND I HAD MONITORED XMISSIONS THAT MADE ME BELIEVE IT WAS NOT AT ARPT, BUT WAS SETTING UP FOR AN APCH. ON GND, I CALLED TWR TO DISCUSS AND ACKNOWLEDGED FAILURE TO CALL OM, AND LEARNED THAT THEY DO NOT HAVE RADAR AT THEIR TWR. DTN SITS UNDER THE SHV-BAD CLASS C, AND I NEVER RECEIVED ANY INDICATION THAT RADAR SEPARATION WAS BEING DISCONTINUED. CORRECTIVE ACTION: MORE ATTN TO COM PROCS TO CALL OM (FOR ME). FOR OTHER ACFT: CFI OUGHT TO BE LOOKING OUTSIDE OF COCKPIT (THEY NEVER SAW ME). TWR: NEEDS RADAR. APCH: WHEN HANDLING TFC IN IMC NEEDS TO CLARIFY/EMPHASIZE CANCELLATION OF RADAR SVCS.

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.