Piper pilot reports CTAF frequency error on commercial chart for tzt.

Attributes
ACN	759932
Time
Date	200711
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : tzt.airport
State Reference	IA
Altitude	msl single value : 3500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : cid.tracon
Operator	general aviation : instructional
Make Model Name	Piper Aircraft Corp Undifferentiated or Other Model
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	approach : instrument non precision
Flight Plan	None
Person 1
Affiliation	other
Function	instruction : instructor
Qualification	pilot : multi engine pilot : instrument pilot : cfi pilot : atp
Experience	flight time last 90 days : 75 flight time total : 7000 flight time type : 3000
ASRS Report	759932
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	FAA Chart Or Publication
Primary Problem	Ambiguous
Situations
Chart	airport : tzt.airport

Narrative:

Executing practice GPS 18 approach to belle plaine; ia (tzt). Using FAA instrument approach charts and noticed the unicom frequency was 122.9. I've given instruction for many years in this area and the unicom has always been 122.8. We were receiving radar advisories from cedar rapids approach and asked them about the unicom frequency. They first said 122.8 but then said 122.9. Didn't see any NOTAM or receive any notice through faasafety.government about any frequency change. Also; the pilot controlled lights are still on 122.8. In my view this makes tzt a 'hotspot' with great potential for conflicts between airplanes.callback conversation with reporter revealed the following information: the reporter stated the main complaint is that the CTAF frequency had changed at tzt without any notification. Pilots who fly frequently often recall frequencies from memory which could allow two aircraft to be announcing positions on different frequencies. Reporter feels these changes should be widely disseminated through long termed NOTAMS and aviation safety forums.

Original NASA ASRS Text

Title: PIPER PLT RPTS CTAF FREQUENCY ERROR ON COMMERCIAL CHART FOR TZT.

Narrative: EXECUTING PRACTICE GPS 18 APCH TO BELLE PLAINE; IA (TZT). USING FAA INSTRUMENT APCH CHARTS AND NOTICED THE UNICOM FREQUENCY WAS 122.9. I'VE GIVEN INSTRUCTION FOR MANY YEARS IN THIS AREA AND THE UNICOM HAS ALWAYS BEEN 122.8. WE WERE RECEIVING RADAR ADVISORIES FROM CEDAR RAPIDS APCH AND ASKED THEM ABOUT THE UNICOM FREQUENCY. THEY FIRST SAID 122.8 BUT THEN SAID 122.9. DIDN'T SEE ANY NOTAM OR RECEIVE ANY NOTICE THROUGH FAASAFETY.GOV ABOUT ANY FREQUENCY CHANGE. ALSO; THE PLT CONTROLLED LIGHTS ARE STILL ON 122.8. IN MY VIEW THIS MAKES TZT A 'HOTSPOT' WITH GREAT POTENTIAL FOR CONFLICTS BETWEEN AIRPLANES.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE MAIN COMPLAINT IS THAT THE CTAF FREQ HAD CHANGED AT TZT WITHOUT ANY NOTIFICATION. PLTS WHO FLY FREQUENTLY OFTEN RECALL FREQUENCIES FROM MEMORY WHICH COULD ALLOW TWO ACFT TO BE ANNOUNCING POSITIONS ON DIFFERENT FREQUENCIES. RPTR FEELS THESE CHANGES SHOULD BE WIDELY DISSEMINATED THROUGH LONG TERMED NOTAMS AND AVIATION SAFETY FORUMS.

Data retrieved from NASA's ASRS site as of January 2009 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.