Unauthorized penetration of airspace. Proximity of arsa.

Attributes
ACN	239753
Time
Date	199304
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz
State Reference	US
Altitude	msl bound lower : 1950 msl bound upper : 2050
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Controlling Facilities	tracon : zzz
Operator	general aviation : corporate
Make Model Name	Helicopter
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 40 flight time total : 5000 flight time type : 700
ASRS Report	239753
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe non adherence : far other anomaly other other anomaly other
Independent Detector	atc equipment other atc equipment : unspecified
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was in level flight under the ZZZ arsa at 1950 ft MSL. The floor of the arsa is 2000 ft where I was. The reason I am sending this in, is that sometimes the ZZZ radar will have me up to 100 ft off the altitude that my altimeter reads. So, by their radar, I could have been between 1850 ft and 2050 ft MSL. The latter would put me in the arsa by 50 ft. My altimeter was set correctly at the time. Callback conversation with reporter revealed the following: reporter states that error in altitude reading between the aircraft and ATC has not been confirmed to be an aircraft altimeter error. Reporter states that error must be in mode C. Reporter was en route to hospital with patient on interfacility transfer.

Original NASA ASRS Text

Title: UNAUTH PENETRATION OF AIRSPACE. PROX OF ARSA.

Narrative: I WAS IN LEVEL FLT UNDER THE ZZZ ARSA AT 1950 FT MSL. THE FLOOR OF THE ARSA IS 2000 FT WHERE I WAS. THE REASON I AM SENDING THIS IN, IS THAT SOMETIMES THE ZZZ RADAR WILL HAVE ME UP TO 100 FT OFF THE ALT THAT MY ALTIMETER READS. SO, BY THEIR RADAR, I COULD HAVE BEEN BTWN 1850 FT AND 2050 FT MSL. THE LATTER WOULD PUT ME IN THE ARSA BY 50 FT. MY ALTIMETER WAS SET CORRECTLY AT THE TIME. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: RPTR STATES THAT ERROR IN ALT READING BTWN THE ACFT AND ATC HAS NOT BEEN CONFIRMED TO BE AN ACFT ALTIMETER ERROR. RPTR STATES THAT ERROR MUST BE IN MODE C. RPTR WAS ENRTE TO HOSPITAL WITH PATIENT ON INTERFAC TRANSFER.

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.