GA pilot believes tfr altitudes should be shown in ft above MSL rather than ft AGL.

Attributes
ACN	614339
Time
Date	200404
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : tth.vortac
State Reference	IN
Altitude	msl single value : 5000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Navigation In Use	other other
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	controller : radar controller : non radar controller : military pilot : commercial pilot : instrument
Experience	controller military : 1 controller non radar : 25 controller radar : 15 flight time last 90 days : 20 flight time total : 3000 flight time type : 800
ASRS Report	614339
Person 2
Affiliation	government : faa
Function	controller : approach
Events
Anomaly	airspace violation : entry non adherence : far
Independent Detector	atc equipment other atc equipment : radar/ mode c other controllera other flight crewa
Supplementary
Problem Areas	Flight Crew Human Performance Airspace Structure
Primary Problem	Ambiguous

Narrative:

The FSS WX briefing at XA00 that morning included the location of the above tfr. Apparently I wrote 5000 ft MSL instead of 5000 ft AGL as the top of the tfr area. With a +/-500 ft ground level, this put me 100 ft below the top of the tfr area (cruise altitude of 5500 ft MSL). I would urge that tfr tops be given in ft above MSL. Was the decision to use AGL made by a non pilot? Some charts may not show a ground level in the tfr zone. Callback conversation with reporter revealed the following information: reporter said the tfr was a 5 mi radius and believed it was for a power plant in the area. He said he was not requested to call ATC after landing or asked for pilot information.

Original NASA ASRS Text

Title: GA PLT BELIEVES TFR ALTS SHOULD BE SHOWN IN FT ABOVE MSL RATHER THAN FT AGL.

Narrative: THE FSS WX BRIEFING AT XA00 THAT MORNING INCLUDED THE LOCATION OF THE ABOVE TFR. APPARENTLY I WROTE 5000 FT MSL INSTEAD OF 5000 FT AGL AS THE TOP OF THE TFR AREA. WITH A +/-500 FT GND LEVEL, THIS PUT ME 100 FT BELOW THE TOP OF THE TFR AREA (CRUISE ALT OF 5500 FT MSL). I WOULD URGE THAT TFR TOPS BE GIVEN IN FT ABOVE MSL. WAS THE DECISION TO USE AGL MADE BY A NON PLT? SOME CHARTS MAY NOT SHOW A GND LEVEL IN THE TFR ZONE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR SAID THE TFR WAS A 5 MI RADIUS AND BELIEVED IT WAS FOR A PWR PLANT IN THE AREA. HE SAID HE WAS NOT REQUESTED TO CALL ATC AFTER LNDG OR ASKED FOR PLT INFO.

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.