|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1801 To 2400|
|Locale Reference||atc facility : sea|
airport : bfi
|Altitude||msl bound lower : 2980|
msl bound upper : 3000
|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|
|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
|Anomaly||non adherence : far|
other anomaly other
|Independent Detector||other controllera|
|Resolutory Action||none taken : anomaly accepted|
|Consequence||faa : reviewed incident with flight crew|
|Primary Problem||Flight Crew Human Performance|
|Air Traffic Incident||Pilot Deviation|
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.