Small aircraft penetrates atl TCA due to a navigation error.

Attributes
ACN	141213
Time
Date	199003
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mcn
State Reference	GA
Altitude	msl bound lower : 10500 msl bound upper : 10500
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : atl
Operator	general aviation : instructional
Make Model Name	Small Aircraft, High Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 2500 flight time type : 500
ASRS Report	141213
Person 2
Affiliation	government : faa
Function	other personnel other
Qualification	other
Events
Anomaly	airspace violation : entry non adherence : far other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : exited penetrated airspace
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While flying over a broken cloud layer, I was dictating an IFR flight plan to the macon FSS. As I completed the dictation and was listening for the FSS reply, I noticed the airspace alert on the LORAN C flashing. Checking the airspace mode we were approximately 1 NM inside the southern perimeter of the atlanta TCA (TCA bottom is 10000'). We immediately exited the TCA. At the time we entered the TCA I was navigating off the macon and la grange vors frequency 114.2 and 115.6, respectively. According to the signals and indications we were receiving we cross-checked our position. We should have been approximately 3 NM south of the TCA. I could not get a good ground fix due to the broken layer, however, past experience has shown the LORAN C to be much more accurate than the VOR system. I recommend the FAA review the geometry of the TCA system. A curved surface is most difficult to define in space off a VOR navigation fix. A square TCA would be easier to identify.

Original NASA ASRS Text

Title: SMA PENETRATES ATL TCA DUE TO A NAVIGATION ERROR.

Narrative: WHILE FLYING OVER A BROKEN CLOUD LAYER, I WAS DICTATING AN IFR FLT PLAN TO THE MACON FSS. AS I COMPLETED THE DICTATION AND WAS LISTENING FOR THE FSS REPLY, I NOTICED THE AIRSPACE ALERT ON THE LORAN C FLASHING. CHECKING THE AIRSPACE MODE WE WERE APPROX 1 NM INSIDE THE SOUTHERN PERIMETER OF THE ATLANTA TCA (TCA BOTTOM IS 10000'). WE IMMEDIATELY EXITED THE TCA. AT THE TIME WE ENTERED THE TCA I WAS NAVIGATING OFF THE MACON AND LA GRANGE VORS FREQ 114.2 AND 115.6, RESPECTIVELY. ACCORDING TO THE SIGNALS AND INDICATIONS WE WERE RECEIVING WE CROSS-CHECKED OUR POSITION. WE SHOULD HAVE BEEN APPROX 3 NM S OF THE TCA. I COULD NOT GET A GOOD GND FIX DUE TO THE BROKEN LAYER, HOWEVER, PAST EXPERIENCE HAS SHOWN THE LORAN C TO BE MUCH MORE ACCURATE THAN THE VOR SYSTEM. I RECOMMEND THE FAA REVIEW THE GEOMETRY OF THE TCA SYSTEM. A CURVED SURFACE IS MOST DIFFICULT TO DEFINE IN SPACE OFF A VOR NAVIGATION FIX. A SQUARE TCA WOULD BE EASIER TO IDENTIFY.

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.