Air carrier inadvertently leaves control frequency causing traffic conflict.

Attributes
ACN	476335
Time
Date	200006
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : mtc.airport
State Reference	MI
Altitude	msl single value : 2500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Falcon 20FJF/20C/20D/20E/20F
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : multi engine
Experience	flight time last 90 days : 120 flight time total : 3600 flight time type : 1800
ASRS Report	476335
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Events
Anomaly	conflict : airborne critical non adherence : published procedure other anomaly other other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : became reoriented flight crew : overcame equipment problem other
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

I was flying. My first officer was doing the radio work. We were talking to selfange approach. He gave us a vector and told us to report the airport in sight. I instructed my first officer to make position reports to CTAF. The first officer accidentally switched off the approach controller and went directly to the CTAF frequency. After approximately 1 min, we saw 2 other aircraft, went around them to enter the pattern. I looked down on the radio panel because I hadn't heard from ATC and discovered the approach frequency had been off. I immediately contacted approach on the appropriate frequency, and he stated that we almost ran into other aircraft. We apologized and landed without incident.

Original NASA ASRS Text

Title: ACR INADVERTENTLY LEAVES CTL FREQ CAUSING TFC CONFLICT.

Narrative: I WAS FLYING. MY FO WAS DOING THE RADIO WORK. WE WERE TALKING TO SELFANGE APCH. HE GAVE US A VECTOR AND TOLD US TO RPT THE ARPT IN SIGHT. I INSTRUCTED MY FO TO MAKE POS RPTS TO CTAF. THE FO ACCIDENTALLY SWITCHED OFF THE APCH CTLR AND WENT DIRECTLY TO THE CTAF FREQ. AFTER APPROX 1 MIN, WE SAW 2 OTHER ACFT, WENT AROUND THEM TO ENTER THE PATTERN. I LOOKED DOWN ON THE RADIO PANEL BECAUSE I HADN'T HEARD FROM ATC AND DISCOVERED THE APCH FREQ HAD BEEN OFF. I IMMEDIATELY CONTACTED APCH ON THE APPROPRIATE FREQ, AND HE STATED THAT WE ALMOST RAN INTO OTHER ACFT. WE APOLOGIZED AND LANDED WITHOUT INCIDENT.

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.