Reported problems holding heading and altitude due to WX. Moderate to severe turbulence chop.

Attributes
ACN	389428
Time
Date	199712
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sfo
State Reference	CA
Altitude	msl bound lower : 2100 msl bound upper : 2100
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oak
Operator	general aviation : instructional
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	other other : other pilot : cfi pilot : commercial pilot : instrument
Experience	flight time last 90 days : 6 flight time total : 300 flight time type : 50
ASRS Report	389428
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather other anomaly other other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	other

Narrative:

I was doing a 'bay tour' on this afternoon. I departed from rhv at XX45. After takeoff, I remained clear of sjc class C as instructed. I intended to fly to sfo then over the golden gate bridge. After many vectors, I finally flew over the bridge, after receiving clearance to enter sfo class B airspace. Over the bridge, the controller said 'resume own navigation' so I informed him I would like to proceed direct sjc if able and informed the controller of my heading. About 1 min later, he said 'you just busted class B airspace without a clearance.' he gave me a heading of north for about 5 mi then apologized and gave further instructions. After a controller handoff, I proceeded across the bay towards oakland and south down the east bay to rhv. This new controller gave me a 090 degree heading but moderate turbulence with severe chop made it impossible to hold a constant heading. This controller also inquired about my heading deviation. I believe both occurrences were the result of several factors including controller workload, miscom between myself and the controller, and WX factors affected my heading deviation. Additionally, altitude restrs prevented me from flying a 090 degree heading due to terrain over fremont area and prevented a constant altitude. My altitude varied as much as 300 ft due to turbulence and updrafts/downdrafts. Moderate/severe turbulence had been reported earlier that day. Ensuring full understanding of directions would prevent future occurrences.

Original NASA ASRS Text

Title: RPTED PROBS HOLDING HDG AND ALT DUE TO WX. MODERATE TO SEVERE TURB CHOP.

Narrative: I WAS DOING A 'BAY TOUR' ON THIS AFTERNOON. I DEPARTED FROM RHV AT XX45. AFTER TKOF, I REMAINED CLR OF SJC CLASS C AS INSTRUCTED. I INTENDED TO FLY TO SFO THEN OVER THE GOLDEN GATE BRIDGE. AFTER MANY VECTORS, I FINALLY FLEW OVER THE BRIDGE, AFTER RECEIVING CLRNC TO ENTER SFO CLASS B AIRSPACE. OVER THE BRIDGE, THE CTLR SAID 'RESUME OWN NAV' SO I INFORMED HIM I WOULD LIKE TO PROCEED DIRECT SJC IF ABLE AND INFORMED THE CTLR OF MY HDG. ABOUT 1 MIN LATER, HE SAID 'YOU JUST BUSTED CLASS B AIRSPACE WITHOUT A CLRNC.' HE GAVE ME A HDG OF N FOR ABOUT 5 MI THEN APOLOGIZED AND GAVE FURTHER INSTRUCTIONS. AFTER A CTLR HDOF, I PROCEEDED ACROSS THE BAY TOWARDS OAKLAND AND S DOWN THE EAST BAY TO RHV. THIS NEW CTLR GAVE ME A 090 DEG HDG BUT MODERATE TURB WITH SEVERE CHOP MADE IT IMPOSSIBLE TO HOLD A CONSTANT HDG. THIS CTLR ALSO INQUIRED ABOUT MY HDG DEV. I BELIEVE BOTH OCCURRENCES WERE THE RESULT OF SEVERAL FACTORS INCLUDING CTLR WORKLOAD, MISCOM BTWN MYSELF AND THE CTLR, AND WX FACTORS AFFECTED MY HDG DEV. ADDITIONALLY, ALT RESTRS PREVENTED ME FROM FLYING A 090 DEG HDG DUE TO TERRAIN OVER FREMONT AREA AND PREVENTED A CONSTANT ALT. MY ALT VARIED AS MUCH AS 300 FT DUE TO TURB AND UPDRAFTS/DOWNDRAFTS. MODERATE/SEVERE TURB HAD BEEN RPTED EARLIER THAT DAY. ENSURING FULL UNDERSTANDING OF DIRECTIONS WOULD PREVENT FUTURE OCCURRENCES.

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.