Evaluation of approach procedure.

Attributes
ACN	300953
Time
Date	199504
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : isfo airport : sfo
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : sfo
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	approach : straight in arrival other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	300953
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

An MD80 was executing lda DME runway 28R and we were IMC for runway 28L. The tower cleared the MD80 to land on runway 28L (our runway) before we were in VMC conditions. After we broke out to VMC we could see the jet at our 12 O'clock 2 mi ahead. We were then cleared to land runway 28R. I immediately leveled off to stay above the jet's wake turbulence and turned to intercept the centerline of runway 28R. I flew 1 DOT above the GS to prevent a wake encounter. Winds were 200 degrees at 09 KTS thus the jet's wake was drifting onto the extended centerline of runway 28R. At 700 ft we encountered light chop and some right rolling action that seemed like wake turbulence. If I had been on the GS when I transitioned to the right runway I believe we would have hit his wake much more severely. My advice for these arrs: 1) approach to right, land on right, approachs to left, land on left. 2) to avoid wake encounters have the 2 aircraft close together (3/4 mi) end to end or as close to 3/4 mi end to end as possible. If not, use 5 mi end to end stagger.

Original NASA ASRS Text

Title: EVALUATION OF APCH PROC.

Narrative: AN MD80 WAS EXECUTING LDA DME RWY 28R AND WE WERE IMC FOR RWY 28L. THE TWR CLRED THE MD80 TO LAND ON RWY 28L (OUR RWY) BEFORE WE WERE IN VMC CONDITIONS. AFTER WE BROKE OUT TO VMC WE COULD SEE THE JET AT OUR 12 O'CLOCK 2 MI AHEAD. WE WERE THEN CLRED TO LAND RWY 28R. I IMMEDIATELY LEVELED OFF TO STAY ABOVE THE JET'S WAKE TURB AND TURNED TO INTERCEPT THE CTRLINE OF RWY 28R. I FLEW 1 DOT ABOVE THE GS TO PREVENT A WAKE ENCOUNTER. WINDS WERE 200 DEGS AT 09 KTS THUS THE JET'S WAKE WAS DRIFTING ONTO THE EXTENDED CTRLINE OF RWY 28R. AT 700 FT WE ENCOUNTERED LIGHT CHOP AND SOME R ROLLING ACTION THAT SEEMED LIKE WAKE TURB. IF I HAD BEEN ON THE GS WHEN I TRANSITIONED TO THE R RWY I BELIEVE WE WOULD HAVE HIT HIS WAKE MUCH MORE SEVERELY. MY ADVICE FOR THESE ARRS: 1) APCH TO R, LAND ON R, APCHS TO L, LAND ON L. 2) TO AVOID WAKE ENCOUNTERS HAVE THE 2 ACFT CLOSE TOGETHER (3/4 MI) END TO END OR AS CLOSE TO 3/4 MI END TO END AS POSSIBLE. IF NOT, USE 5 MI END TO END STAGGER.

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.