A CFI in a rented C172 enters the 30 mi veil of mem with an inoperative transponder.

Attributes
ACN	437420
Time
Date	199905
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : mem.airport
State Reference	TN
Altitude	msl single value : 4500
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : mem.tracon
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Navigation In Use	other
Flight Phase	cruise : level
Route In Use	enroute : direct
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument pilot : cfi pilot : multi engine
Experience	flight time last 90 days : 71 flight time total : 740 flight time type : 18
ASRS Report	437420
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe airspace violation : entry maintenance problem : improper maintenance non adherence : far
Independent Detector	other flight crewa
Resolutory Action	flight crew : became reoriented flight crew : exited penetrated airspace
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft Airspace Structure Maintenance Human Performance
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

I was flying a rental aircraft which I learned had transponder troubles after I departed. I was flying northwest at 4500 ft near tunica, ms. This kept me below the class B airspace but within the mode C veil. I was about 2-3 NM inside the mode C veil. When I realized that I was in the veil and my transponder was intermittent I immediately turned to exit the mode C veil. I had forgotten about my mode C transponder problems when I entered the mode C veil. I was within the veil approximately 2-3 mi and only briefly. I never entered class B airspace. There never was a traffic conflict. Contributing factors -- rental aircraft. I've never flown a plane with transponder troubles before. It was late at night so I didn't think as clearly as I should have.

Original NASA ASRS Text

Title: A CFI IN A RENTED C172 ENTERS THE 30 MI VEIL OF MEM WITH AN INOP XPONDER.

Narrative: I WAS FLYING A RENTAL ACFT WHICH I LEARNED HAD XPONDER TROUBLES AFTER I DEPARTED. I WAS FLYING NW AT 4500 FT NEAR TUNICA, MS. THIS KEPT ME BELOW THE CLASS B AIRSPACE BUT WITHIN THE MODE C VEIL. I WAS ABOUT 2-3 NM INSIDE THE MODE C VEIL. WHEN I REALIZED THAT I WAS IN THE VEIL AND MY XPONDER WAS INTERMITTENT I IMMEDIATELY TURNED TO EXIT THE MODE C VEIL. I HAD FORGOTTEN ABOUT MY MODE C XPONDER PROBS WHEN I ENTERED THE MODE C VEIL. I WAS WITHIN THE VEIL APPROX 2-3 MI AND ONLY BRIEFLY. I NEVER ENTERED CLASS B AIRSPACE. THERE NEVER WAS A TFC CONFLICT. CONTRIBUTING FACTORS -- RENTAL ACFT. I'VE NEVER FLOWN A PLANE WITH XPONDER TROUBLES BEFORE. IT WAS LATE AT NIGHT SO I DIDN'T THINK AS CLRLY AS I SHOULD HAVE.

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.