Air carrier X light transport encountered wake turbulence behind air carrier Y widebody transport flight attendant injury. Reporter alleges separation criteria is insufficient.

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Attributes
ACN	225034
Time
Date	199210
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : sfo
State Reference	CA
Altitude	msl bound lower : 5500 msl bound upper : 5500
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oak
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Navigation In Use	Other
Flight Phase	descent : approach descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 4 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	225034
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

I believe 'standard separation' is insufficient between the widebody transport and my aircraft, an light transport. This opinion is based on 3 wake turbulence encounters in 1 week. Air carrier Y and my air carrier X arrive at sfo at the same time in the morning. All 3 times were in very calm air. 1) oct/X/92. On final, 5 mi behind in clouds, hit significant wake. 2) oct/Y/92. On descent through 5500 (from 6000 to 4000 was clearance) and while being vectored in clouds. Complained to ATC and was told the aircraft was 6 mi ahead. I requested more separation. ATC said unable. Minor injury to flight attendant. 3) oct/Z/92. On final, 7 mi behind, over 1 DOT high. Minor encounter. My procedure is now to whine at ATC for more separation and make sure the airplane is a minimum 1 1/2 - 2 dots high when behind the widebody transport. Anything less has shown to be inadequate, risking significant injury to my flight attendant and scaring my passenger. Also, my flight attendant is forewarned and is seated much earlier than company procedures call for.

Original NASA ASRS Text

Title: ACR X LTT ENCOUNTERED WAKE TURB BEHIND ACR Y WDB FLIGHT ATTENDANT INJURY. RPTR ALLEGES SEPARATION CRITERIA IS INSUFFICIENT.

Narrative: I BELIEVE 'STANDARD SEPARATION' IS INSUFFICIENT BTWN THE WDB AND MY ACFT, AN LTT. THIS OPINION IS BASED ON 3 WAKE TURB ENCOUNTERS IN 1 WK. ACR Y AND MY ACR X ARRIVE AT SFO AT THE SAME TIME IN THE MORNING. ALL 3 TIMES WERE IN VERY CALM AIR. 1) OCT/X/92. ON FINAL, 5 MI BEHIND IN CLOUDS, HIT SIGNIFICANT WAKE. 2) OCT/Y/92. ON DSCNT THROUGH 5500 (FROM 6000 TO 4000 WAS CLRNC) AND WHILE BEING VECTORED IN CLOUDS. COMPLAINED TO ATC AND WAS TOLD THE ACFT WAS 6 MI AHEAD. I REQUESTED MORE SEPARATION. ATC SAID UNABLE. MINOR INJURY TO FLIGHT ATTENDANT. 3) OCT/Z/92. ON FINAL, 7 MI BEHIND, OVER 1 DOT HIGH. MINOR ENCOUNTER. MY PROC IS NOW TO WHINE AT ATC FOR MORE SEPARATION AND MAKE SURE THE AIRPLANE IS A MINIMUM 1 1/2 - 2 DOTS HIGH WHEN BEHIND THE WDB. ANYTHING LESS HAS SHOWN TO BE INADEQUATE, RISKING SIGNIFICANT INJURY TO MY FLIGHT ATTENDANT AND SCARING MY PAX. ALSO, MY FLT ATTENDANT IS FOREWARNED AND IS SEATED MUCH EARLIER THAN COMPANY PROCS CALL FOR.

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.