A B747-400 on the gapp 3 SID out of sfo experienced an near midair collision with a cessna.

Attributes
ACN	453956
Time
Date	199910
Day	Sat
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : sfo.airport
State Reference	CA
Altitude	msl single value : 2500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : o90.tracon
Operator	common carrier : air carrier
Make Model Name	B747-400
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : initial
Route In Use	departure sid : gapp 3
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : o90.tracon
Operator	general aviation : personal
Make Model Name	Cessna Single Piston Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp pilot : multi engine
Experience	flight time last 90 days : 250 flight time total : 25000 flight time type : 2000
ASRS Report	453956
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	conflict : nmac non adherence : required legal separation non adherence : far non adherence : clearance
Independent Detector	atc equipment : conflict alert aircraft equipment : tcas other controllera other flight crewa other flight crewb other other : 3
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew other
Miss Distance	horizontal : 200 vertical : 0
Supplementary
Problem Areas	Airspace Structure Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

Experienced near midair collision while on GAPP3.sfo departure. Followed bay departure controller's instructions to turn left immediately to heading 190 degrees, followed by a yellow TCASII TA. Expedited turn further because of TCASII display and controller's further urgency. PNF first officer observed small, high wing, single engine cessna pass to our starboard side through the lower right corner of window R3. The cessna was of an X color. We were then cleared direct to alcoa and proceeded on course. Contacted dispatcher through ACARS. I talked to dispatcher via conference phone upon our arrival nrt. He then patched crew to sfo bay departure watch supervisor. All 3 pilots agreed that a probable collision hazard existed between 2 aircraft and so stated.

Original NASA ASRS Text

Title: A B747-400 ON THE GAPP 3 SID OUT OF SFO EXPERIENCED AN NMAC WITH A CESSNA.

Narrative: EXPERIENCED NMAC WHILE ON GAPP3.SFO DEP. FOLLOWED BAY DEP CTLR'S INSTRUCTIONS TO TURN L IMMEDIATELY TO HDG 190 DEGS, FOLLOWED BY A YELLOW TCASII TA. EXPEDITED TURN FURTHER BECAUSE OF TCASII DISPLAY AND CTLR'S FURTHER URGENCY. PNF FO OBSERVED SMALL, HIGH WING, SINGLE ENG CESSNA PASS TO OUR STARBOARD SIDE THROUGH THE LOWER R CORNER OF WINDOW R3. THE CESSNA WAS OF AN X COLOR. WE WERE THEN CLRED DIRECT TO ALCOA AND PROCEEDED ON COURSE. CONTACTED DISPATCHER THROUGH ACARS. I TALKED TO DISPATCHER VIA CONFERENCE PHONE UPON OUR ARR NRT. HE THEN PATCHED CREW TO SFO BAY DEP WATCH SUPVR. ALL 3 PLTS AGREED THAT A PROBABLE COLLISION HAZARD EXISTED BTWN 2 ACFT AND SO STATED.

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.