An small aircraft helicopter pilot failed to turn his transponder to 'on' or 'altitude reporting.'

Attributes
ACN	316530
Time
Date	199509
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : cgx
State Reference	IL
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : instructional
Make Model Name	Helicopter
Operating Under FAR Part	Part 91
Flight Phase	ground : preflight other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 20 flight time total : 170 flight time type : 150
ASRS Report	316530
Events
Anomaly	non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I forgot to switch transponder from 'standby' to 'altitude' prior to takeoff from 3HA. I proceeded north to cgx, thus entering the mode C area with the transponder still in 'standby' mode. I landed about 20 mins later at cgx. Prior to departing from cgx, I realized the error and turned the transponder to 'altitude encoding' for the remainder of the flight. I did not follow the checklist closely. Also, is there a good reason not to leave the transponder in the 'altitude' position always?

Original NASA ASRS Text

Title: AN SMA HELI PLT FAILED TO TURN HIS XPONDER TO 'ON' OR 'ALT RPTING.'

Narrative: I FORGOT TO SWITCH XPONDER FROM 'STANDBY' TO 'ALT' PRIOR TO TKOF FROM 3HA. I PROCEEDED N TO CGX, THUS ENTERING THE MODE C AREA WITH THE XPONDER STILL IN 'STANDBY' MODE. I LANDED ABOUT 20 MINS LATER AT CGX. PRIOR TO DEPARTING FROM CGX, I REALIZED THE ERROR AND TURNED THE XPONDER TO 'ALT ENCODING' FOR THE REMAINDER OF THE FLT. I DID NOT FOLLOW THE CHKLIST CLOSELY. ALSO, IS THERE A GOOD REASON NOT TO LEAVE THE XPONDER IN THE 'ALT' POS ALWAYS?

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.