Parallel visual approachs cause barrage of TCASII commands.

Attributes
ACN	252111
Time
Date	199309
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sfo
State Reference	CA
Altitude	msl bound lower : 1800 msl bound upper : 1800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : sfo
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Aircraft 2
Operator	general aviation : corporate
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 10000 flight time type : 2000
ASRS Report	252111
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : clearance non adherence other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

On visual to runway 28L at sfo. About 15 mi out (near menlo) we were told we would be along side an light transport, presently on downwind, call in sight. We called in sight, as did light transport. Both cleared for runway 28L and runway 28R, respectively. On final from brijj OM, we lost sight visually, but had traffic behind us on TCASII. Display looked as if light transport was lined up for runway 28L. TCASII was screaming at us all the way down, first red, then yellow every few seconds. Whenever red we'd comply with TCASII commands, then it would go yellow again. We tried repeatedly to query sfo tower about light transport's location but couldn't get a word in edgewise, because tower was rattling off commands without pause in an effort to squeeze out departures off runway 1L&right. Finally, we landed without incident, but we never were able to tell tower that we'd lost sight of light transport, nor were we able to find out if light transport still had us in sight. Unnerving. The tower should not transmit continuously without allowing time for responses, and shouldn't try to squeeze out so many crossing departures.

Original NASA ASRS Text

Title: PARALLEL VISUAL APCHS CAUSE BARRAGE OF TCASII COMMANDS.

Narrative: ON VISUAL TO RWY 28L AT SFO. ABOUT 15 MI OUT (NEAR MENLO) WE WERE TOLD WE WOULD BE ALONG SIDE AN LTT, PRESENTLY ON DOWNWIND, CALL IN SIGHT. WE CALLED IN SIGHT, AS DID LTT. BOTH CLRED FOR RWY 28L AND RWY 28R, RESPECTIVELY. ON FINAL FROM BRIJJ OM, WE LOST SIGHT VISUALLY, BUT HAD TFC BEHIND US ON TCASII. DISPLAY LOOKED AS IF LTT WAS LINED UP FOR RWY 28L. TCASII WAS SCREAMING AT US ALL THE WAY DOWN, FIRST RED, THEN YELLOW EVERY FEW SECONDS. WHENEVER RED WE'D COMPLY WITH TCASII COMMANDS, THEN IT WOULD GO YELLOW AGAIN. WE TRIED REPEATEDLY TO QUERY SFO TWR ABOUT LTT'S LOCATION BUT COULDN'T GET A WORD IN EDGEWISE, BECAUSE TWR WAS RATTLING OFF COMMANDS WITHOUT PAUSE IN AN EFFORT TO SQUEEZE OUT DEPS OFF RWY 1L&R. FINALLY, WE LANDED WITHOUT INCIDENT, BUT WE NEVER WERE ABLE TO TELL TWR THAT WE'D LOST SIGHT OF LTT, NOR WERE WE ABLE TO FIND OUT IF LTT STILL HAD US IN SIGHT. UNNERVING. THE TWR SHOULD NOT XMIT CONTINUOUSLY WITHOUT ALLOWING TIME FOR RESPONSES, AND SHOULDN'T TRY TO SQUEEZE OUT SO MANY XING DEPS.

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.