C172 pilot had the aircraft ELT block communication with ground.

Attributes
ACN	437277
Time
Date	199905
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : mpv.airport
State Reference	NH
Altitude	msl single value : 7000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	ground : takeoff roll
Flight Plan	VFR
Person 1
Affiliation	company : corporate
Function	flight crew : single pilot
Qualification	pilot : private pilot : multi engine pilot : instrument
Experience	flight time last 90 days : 20 flight time total : 230 flight time type : 150
ASRS Report	437277
Person 2
Affiliation	government : faa
Function	other personnel
Qualification	other
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	other flight crewa
Resolutory Action	flight crew : diverted to another airport flight crew : landed as precaution
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

In cruise climb to 7500 MSL the ELT in the aircraft activated at approximately 7000 ft MSL. PIC was unable to deactivate ELT due to lack of remote switch in cockpit. PIC was also unable to transmit/receive via VHF, because frequencys were blocked by ELT xmissions. PIC contacted btv AFSS, via cellular phone, airborne, to advise of communication failure and ELT activation and that crew/aircraft were not in distress. PIC returned to departure airport (uncontrolled) to deactivate and re-arm ELT. Mechanic looked at problem and fixed suspect wiring. PIC later departed and flew 8 plus hours without further incident.

Original NASA ASRS Text

Title: C172 PLT HAD THE ACFT ELT BLOCK COM WITH GND.

Narrative: IN CRUISE CLB TO 7500 MSL THE ELT IN THE ACFT ACTIVATED AT APPROX 7000 FT MSL. PIC WAS UNABLE TO DEACTIVATE ELT DUE TO LACK OF REMOTE SWITCH IN COCKPIT. PIC WAS ALSO UNABLE TO XMIT/RECEIVE VIA VHF, BECAUSE FREQS WERE BLOCKED BY ELT XMISSIONS. PIC CONTACTED BTV AFSS, VIA CELLULAR PHONE, AIRBORNE, TO ADVISE OF COM FAILURE AND ELT ACTIVATION AND THAT CREW/ACFT WERE NOT IN DISTRESS. PIC RETURNED TO DEP ARPT (UNCTLED) TO DEACTIVATE AND RE-ARM ELT. MECH LOOKED AT PROB AND FIXED SUSPECT WIRING. PIC LATER DEPARTED AND FLEW 8 PLUS HRS WITHOUT FURTHER 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.