Pilot of C172 on bay tour enters class B airspace by one half mi without clearance. Controller bring...

Attributes
ACN	403030
Time
Date	199805
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : sfo
State Reference	CA
Altitude	msl bound lower : 1900 msl bound upper : 1900
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oak
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : commercial pilot : instrument
Experience	flight time last 90 days : 15 flight time total : 5000 flight time type : 4000
ASRS Report	403030
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	non adherence : far other anomaly other
Independent Detector	other controllera
Resolutory Action	flight crew : became reoriented flight crew : exited penetrated airspace other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Aircraft is a C172A. I requested a 'bay tour' departure from the oak tower with a final destination of the half moon bay airport on the pacific ocean side of san mateo county. I received clearance to fly 'the (bay tour) and remain clear of class B airspace.' I climbed to 1900 ft and maintained that altitude to stay below class B airspace between the 7-10 NM rings of the sfo VOR paralleling the pacific ocean shoreline. On the approximately 270 degree radial of sfo VOR, I drifted inside the 7 NM ring by .5 NM and was advised by the bay TRACON on 135.1 that my altitude at that distance should be 1500 ft. I immediately descended to 1400 ft. I had the VFR terminal chart in my lap and thought I was in compliance but didn't notice the 1/2 drift that brought me inside the 7 mi ring. I incorrectly assumed flying just offshore would keep me clear of the class B airspace. It did not! I had flown this route many times before, but always at 2500 ft outside of the 10 mi ring. On this day, the scattered layer was at 2000 ft and I stayed closer and lower than usual and didn't notice the 6.5 DME indication until I was asked for my altitude. Stupid mistake! Lulled into complacency by former assumptions!

Original NASA ASRS Text

Title: PLT OF C172 ON BAY TOUR ENTERS CLASS B AIRSPACE BY ONE HALF MI WITHOUT CLRNC. CTLR BRINGS IT TO HIS ATTN AND HE CORRECTS.

Narrative: ACFT IS A C172A. I REQUESTED A 'BAY TOUR' DEP FROM THE OAK TWR WITH A FINAL DEST OF THE HALF MOON BAY ARPT ON THE PACIFIC OCEAN SIDE OF SAN MATEO COUNTY. I RECEIVED CLRNC TO FLY 'THE (BAY TOUR) AND REMAIN CLR OF CLASS B AIRSPACE.' I CLBED TO 1900 FT AND MAINTAINED THAT ALT TO STAY BELOW CLASS B AIRSPACE BTWN THE 7-10 NM RINGS OF THE SFO VOR PARALLELING THE PACIFIC OCEAN SHORELINE. ON THE APPROX 270 DEG RADIAL OF SFO VOR, I DRIFTED INSIDE THE 7 NM RING BY .5 NM AND WAS ADVISED BY THE BAY TRACON ON 135.1 THAT MY ALT AT THAT DISTANCE SHOULD BE 1500 FT. I IMMEDIATELY DSNDED TO 1400 FT. I HAD THE VFR TERMINAL CHART IN MY LAP AND THOUGHT I WAS IN COMPLIANCE BUT DIDN'T NOTICE THE 1/2 DRIFT THAT BROUGHT ME INSIDE THE 7 MI RING. I INCORRECTLY ASSUMED FLYING JUST OFFSHORE WOULD KEEP ME CLR OF THE CLASS B AIRSPACE. IT DID NOT! I HAD FLOWN THIS RTE MANY TIMES BEFORE, BUT ALWAYS AT 2500 FT OUTSIDE OF THE 10 MI RING. ON THIS DAY, THE SCATTERED LAYER WAS AT 2000 FT AND I STAYED CLOSER AND LOWER THAN USUAL AND DIDN'T NOTICE THE 6.5 DME INDICATION UNTIL I WAS ASKED FOR MY ALT. STUPID MISTAKE! LULLED INTO COMPLACENCY BY FORMER ASSUMPTIONS!

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.

Pilot of C172 on bay tour enters class B airspace by one half mi without clearance. Controller brings it to his attention and he corrects.