GA small aircraft unauthorized penetfration of airspace.

Attributes
ACN	95450
Time
Date	198809
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : sea airport : bfi
State Reference	WA
Altitude	msl bound lower : 2980 msl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : sea tower : bfi
Operator	general aviation : instructional
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument pilot : cfi
Experience	flight time last 90 days : 270 flight time total : 910 flight time type : 300
ASRS Report	95450
Events
Anomaly	non adherence : far other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Erroneous technology: mode C shows 100-200' higher than actual in the incident aircraft. Confirmed by asking boeing tower for mode C readout, which was 120' above our actual. Boeing tower had informed me that my data block carried a violator flag. About 10 mins earlier I had been accelerating eastbound under the floor of the 3000' sector in preparation for a steep climb upon reaching the 345 degree shelf up to 5000'. I did not climb above 2980' until reaching a one DOT deflection past the 345 degree obs on the VOR, which correlated with ground references beneath the aircraft: webster point light was 1/2 mi behind the aircraft when I commenced the climb. After returning to the west (under the TCA's 3000' sector, 2 mi north of the 1800' sector as confirmed by bfi tower), I asked sea tower for clearance through the sfc sector over the sea airport. I was assigned 2500'. I reported reaching 2500' and was careful to hold that altitude +/- 10'. I expected that sea personnel noted the high altitude readout and deleted my violator flag, because bfi personnel reported no flag upon my return to their frequency. To avoid future situations, change the flagging procedures to match the acceptable limits for altitude reporting equipment errors. There are times when we should be able to use our non TCA airspace within 300' of its limit west/O suffering from techno paranoia!

Original NASA ASRS Text

Title: GA SMA UNAUTH PENETFRATION OF AIRSPACE.

Narrative: ERRONEOUS TECHNOLOGY: MODE C SHOWS 100-200' HIGHER THAN ACTUAL IN THE INCIDENT ACFT. CONFIRMED BY ASKING BOEING TWR FOR MODE C READOUT, WHICH WAS 120' ABOVE OUR ACTUAL. BOEING TWR HAD INFORMED ME THAT MY DATA BLOCK CARRIED A VIOLATOR FLAG. ABOUT 10 MINS EARLIER I HAD BEEN ACCELERATING EBND UNDER THE FLOOR OF THE 3000' SECTOR IN PREPARATION FOR A STEEP CLB UPON REACHING THE 345 DEG SHELF UP TO 5000'. I DID NOT CLB ABOVE 2980' UNTIL REACHING A ONE DOT DEFLECTION PAST THE 345 DEG OBS ON THE VOR, WHICH CORRELATED WITH GND REFERENCES BENEATH THE ACFT: WEBSTER POINT LIGHT WAS 1/2 MI BEHIND THE ACFT WHEN I COMMENCED THE CLB. AFTER RETURNING TO THE W (UNDER THE TCA'S 3000' SECTOR, 2 MI N OF THE 1800' SECTOR AS CONFIRMED BY BFI TWR), I ASKED SEA TWR FOR CLRNC THROUGH THE SFC SECTOR OVER THE SEA ARPT. I WAS ASSIGNED 2500'. I RPTED REACHING 2500' AND WAS CAREFUL TO HOLD THAT ALT +/- 10'. I EXPECTED THAT SEA PERSONNEL NOTED THE HIGH ALT READOUT AND DELETED MY VIOLATOR FLAG, BECAUSE BFI PERSONNEL RPTED NO FLAG UPON MY RETURN TO THEIR FREQ. TO AVOID FUTURE SITUATIONS, CHANGE THE FLAGGING PROCS TO MATCH THE ACCEPTABLE LIMITS FOR ALT RPTING EQUIP ERRORS. THERE ARE TIMES WHEN WE SHOULD BE ABLE TO USE OUR NON TCA AIRSPACE WITHIN 300' OF ITS LIMIT W/O SUFFERING FROM TECHNO PARANOIA!

Data retrieved from NASA's ASRS site as of August 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.