C172 pilot has near midair collision during final approach.

Attributes
ACN	554686
Time
Date	200207
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : hii.airport
State Reference	AZ
Altitude	agl single value : 100
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	descent : vacating altitude descent : approach landing : go around
Route In Use	approach : traffic pattern arrival : vfr
Flight Plan	None
Aircraft 2
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : commercial
Experience	flight time last 90 days : 200 flight time total : 820 flight time type : 150
ASRS Report	554686
Person 2
Affiliation	other
Function	flight crew : single pilot
Events
Anomaly	conflict : nmac non adherence : far non adherence : required legal separation other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action flight crew : executed go around
Miss Distance	horizontal : 0 vertical : 50
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I entered right 45 degrees for runway 14 and was making radio calls on what I thought was CTAF. I saw an aircraft coming north from the river 4 mi out. I lost the traffic on downwind. I saw the aircraft again directly below me on short final and immediately initiated a go around and offset to the right. Other aircraft offset to the left and rest of flight went without incident. My error was communicating on wrong CTAF frequency.

Original NASA ASRS Text

Title: C172 PLT HAS NMAC DURING FINAL APCH.

Narrative: I ENTERED R 45 DEGS FOR RWY 14 AND WAS MAKING RADIO CALLS ON WHAT I THOUGHT WAS CTAF. I SAW AN ACFT COMING N FROM THE RIVER 4 MI OUT. I LOST THE TFC ON DOWNWIND. I SAW THE ACFT AGAIN DIRECTLY BELOW ME ON SHORT FINAL AND IMMEDIATELY INITIATED A GAR AND OFFSET TO THE R. OTHER ACFT OFFSET TO THE L AND REST OF FLT WENT WITHOUT INCIDENT. MY ERROR WAS COMMUNICATING ON WRONG CTAF FREQ.

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.