B737 encounters wake turbulence from B727 on ILS approach. Slows to increase spacing.

Attributes
ACN	449821
Time
Date	199909
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : lax.airport
State Reference	CA
Altitude	msl bound lower : 1500 msl bound upper : 2000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : sct.tracon tower : lax.tower
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 25l
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : sct.tracon tower : lax.tower
Operator	common carrier : air carrier
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 25l
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : atp
Experience	flight time last 90 days : 150 flight time total : 12500 flight time type : 1700
ASRS Report	449821
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : commercial pilot : instrument
Events
Anomaly	inflight encounter : wake turbulence
Independent Detector	other flight crewa
Resolutory Action	flight crew : regained aircraft control other
Supplementary
Problem Areas	Environmental Factor Airspace Structure
Primary Problem	Environmental Factor

Narrative:

During ILS approach runway 25L to lax in IMC about 4 mi in trail of a B727, we encountered 3 successive wake turbulence encounters within a time span of 30 seconds. The first encounter put us in a 20 degree bank with opposite control input being applied. We realized we were in someone's wake and flew high on GS. Even then we received 2 additional rolls which were quickly corrected. We then advised both local and final monitor controller that we were slowing further to increase spacing. These encounters occurred at altitudes from 2000 ft to 1500 ft MSL. Subsequent landing uneventful.

Original NASA ASRS Text

Title: B737 ENCOUNTERS WAKE TURB FROM B727 ON ILS APCH. SLOWS TO INCREASE SPACING.

Narrative: DURING ILS APCH RWY 25L TO LAX IN IMC ABOUT 4 MI IN TRAIL OF A B727, WE ENCOUNTERED 3 SUCCESSIVE WAKE TURB ENCOUNTERS WITHIN A TIME SPAN OF 30 SECONDS. THE FIRST ENCOUNTER PUT US IN A 20 DEG BANK WITH OPPOSITE CTL INPUT BEING APPLIED. WE REALIZED WE WERE IN SOMEONE'S WAKE AND FLEW HIGH ON GS. EVEN THEN WE RECEIVED 2 ADDITIONAL ROLLS WHICH WERE QUICKLY CORRECTED. WE THEN ADVISED BOTH LCL AND FINAL MONITOR CTLR THAT WE WERE SLOWING FURTHER TO INCREASE SPACING. THESE ENCOUNTERS OCCURRED AT ALTS FROM 2000 FT TO 1500 FT MSL. SUBSEQUENT LNDG UNEVENTFUL.

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.