Pilot cites excessive noise in alarm system as pilot distracting and causing altitude deviation.

Attributes
ACN	207902
Time
Date	199204
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ape airport : cmh
State Reference	OH
Altitude	msl bound lower : 6000 msl bound upper : 6400
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : cmh
Operator	general aviation : corporate
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial
Experience	flight time last 90 days : 89 flight time total : 780 flight time type : 450
ASRS Report	207902
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

Aircraft, an small aircraft xy, had alarm (whooper) sound for no apparent reason. Alarm was similar to marker beacon, only 4 times as loud. In ascertaining cause and attempt to shut off alarm, had 400 ft excursion in altitude. Alarm would not shut off. Cause was found to be a broke altitude belt. Advised columbus approach we had apparent electrical problem, alternator/alternator belt, was unsure how long radios would last. Requested vectors to the airport (cmh). Approach preclred me to land on 28R. Radios received but would no longer transmit by short final and were completely dead by engine shutdown. Alarm was going full blast throughout approximately 12-15 mins. Alarm may be part of manufacturers system. A shut off switch or circuit breaker should be incorporated as the alarm is extremely distraction and drains power rapidly. Once the problem is idented, you don't need an alarm screaming in your ear over the speaker system.

Original NASA ASRS Text

Title: PLT CITES EXCESSIVE NOISE IN ALARM SYS AS PLT DISTRACTING AND CAUSING ALTDEV.

Narrative: ACFT, AN SMA XY, HAD ALARM (WHOOPER) SOUND FOR NO APPARENT REASON. ALARM WAS SIMILAR TO MARKER BEACON, ONLY 4 TIMES AS LOUD. IN ASCERTAINING CAUSE AND ATTEMPT TO SHUT OFF ALARM, HAD 400 FT EXCURSION IN ALT. ALARM WOULD NOT SHUT OFF. CAUSE WAS FOUND TO BE A BROKE ALT BELT. ADVISED COLUMBUS APCH WE HAD APPARENT ELECTRICAL PROBLEM, ALTERNATOR/ALTERNATOR BELT, WAS UNSURE HOW LONG RADIOS WOULD LAST. REQUESTED VECTORS TO THE ARPT (CMH). APCH PRECLRED ME TO LAND ON 28R. RADIOS RECEIVED BUT WOULD NO LONGER XMIT BY SHORT FINAL AND WERE COMPLETELY DEAD BY ENG SHUTDOWN. ALARM WAS GOING FULL BLAST THROUGHOUT APPROX 12-15 MINS. ALARM MAY BE PART OF MANUFACTURERS SYS. A SHUT OFF SWITCH OR CIRCUIT BREAKER SHOULD BE INCORPORATED AS THE ALARM IS EXTREMELY DISTR AND DRAINS PWR RAPIDLY. ONCE THE PROBLEM IS IDENTED, YOU DON'T NEED AN ALARM SCREAMING IN YOUR EAR OVER THE SPEAKER SYS.

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.