Controller reporter says there was an near midair collision on the final approach to runway 25L due ...

Attributes
ACN	331843
Time
Date	199603
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dvt
State Reference	AZ
Altitude	msl bound lower : 2000 msl bound upper : 2000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : dvt
Make Model Name	Cessna 210 Centurion / Turbo Centurion 210C, 210D
Operating Under FAR Part	Part 91
Flight Phase	descent : approach landing other
Flight Plan	VFR
Aircraft 2
Make Model Name	PA-28 Cherokee/Archer II/Dakota/Pillan/Warrior
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Flight Plan	VFR
Person 1
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Experience	controller non radar : 1
ASRS Report	331843
Person 2
Affiliation	Other
Function	flight crew : single pilot
Events
Anomaly	conflict : nmac non adherence : far non adherence : clearance
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Miss Distance	horizontal : 450 vertical : 450
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

Near midair collision just east of deer valley airport on final for runway 25L. Centurion inbound from the east making a straight in approach and was told to report a 4 mi final for runway 25L. A cherokee was on left downwind for runway 25R. Traffic was issued to centurion also inbound from the east. Deer valley local listens to 2 frequencys at the same time and this causes much congestion. I believe this was a contributing factor. After traffic was issued to centurion the word 'left' is heard on the tape. This may have been centurion reporting '4 mi final for runway 25L.' controller thought someone said 'blocked so reissued traffic. Centurion responded 'roger looking for traffic from east.' the cherokee turned left base for runway 25R. Centurion is on final but controller never received report of 4 mi final. Cherokee and centurion miss by unknown number of ft on final for runway 25L. Centurion landed without a clearance. Cherokee saw the centurion. I don't believe the centurion ever saw the cherokee. Controller was busy during this period. Centurion should have reported on final again until controller acknowledged. He should not have proceeded inbound and then landed without a clearance.

Original NASA ASRS Text

Title: CTLR RPTR SAYS THERE WAS AN NMAC ON THE FINAL APCH TO RWY 25L DUE TO SMA (X) NOT RPTING A 4 MI FINAL AS REQUESTED. SMA (Y) WAS ON A L BASE FOR RWY 25R AND APPARENTLY SAW AND AVOIDED THE SMA (X). THE SMA (X) ALSO LANDED WITHOUT A CLRNC FROM THE TWR.

Narrative: NMAC JUST E OF DEER VALLEY ARPT ON FINAL FOR RWY 25L. CENTURION INBOUND FROM THE E MAKING A STRAIGHT IN APCH AND WAS TOLD TO RPT A 4 MI FINAL FOR RWY 25L. A CHEROKEE WAS ON L DOWNWIND FOR RWY 25R. TFC WAS ISSUED TO CENTURION ALSO INBOUND FROM THE E. DEER VALLEY LCL LISTENS TO 2 FREQS AT THE SAME TIME AND THIS CAUSES MUCH CONGESTION. I BELIEVE THIS WAS A CONTRIBUTING FACTOR. AFTER TFC WAS ISSUED TO CENTURION THE WORD 'LEFT' IS HEARD ON THE TAPE. THIS MAY HAVE BEEN CENTURION RPTING '4 MI FINAL FOR RWY 25L.' CTLR THOUGHT SOMEONE SAID 'BLOCKED SO REISSUED TFC. CENTURION RESPONDED 'ROGER LOOKING FOR TFC FROM E.' THE CHEROKEE TURNED L BASE FOR RWY 25R. CENTURION IS ON FINAL BUT CTLR NEVER RECEIVED RPT OF 4 MI FINAL. CHEROKEE AND CENTURION MISS BY UNKNOWN NUMBER OF FT ON FINAL FOR RWY 25L. CENTURION LANDED WITHOUT A CLRNC. CHEROKEE SAW THE CENTURION. I DON'T BELIEVE THE CENTURION EVER SAW THE CHEROKEE. CTLR WAS BUSY DURING THIS PERIOD. CENTURION SHOULD HAVE RPTED ON FINAL AGAIN UNTIL CTLR ACKNOWLEDGED. HE SHOULD NOT HAVE PROCEEDED INBOUND AND THEN LANDED WITHOUT A CLRNC.

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.