Reporter in 727 on approach encounters wake turbulence and vortex from 747 6 mi ahead.

Attributes
ACN	298744
Time
Date	199502
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : fra
State Reference	FO
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : fra
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	B747-100
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 150 flight time total : 15000 flight time type : 10000
ASRS Report	298744
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	inflight encounter other
Independent Detector	other flight crewa
Resolutory Action	flight crew : regained aircraft control flight crew : took evasive action flight crew : exited adverse environment
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

Experience: airlines captain instructor 3 yrs. Line check airman 10 yrs. 19 yrs 727 experience. Attorney, some aviation law. On approach runway 25L fra noticed on TCASII traffic ahead 6 mi. Advised by approach it was an air carrier 747. Wind at 4000 ft (omega) 280 degrees at 20 KTS. Advised 747 was on approach to runway 25R, surface wind 250 degrees at 10 KTS. Without any warning, in IMC, the 727 encountered wake turbulence of such magnitude that we rolled about 35-40 degrees with full aileron deflection. I added maximum power to climb and for what was an unusual amount of time the aircraft did not respond. Only once in the past 30 yrs of flying have I been this uncomfortable in a wake encounter and that was 5 mi from an L1011 at 4000 ft in new york. It appears that with the 20 KT wind this turbulence should have dissipated somewhat and not been a severe encounter, especially since we had 5-6 mi separation! I strongly suggest, for safety, we look carefully at our 747 separation standards.

Original NASA ASRS Text

Title: RPTR IN 727 ON APCH ENCOUNTERS WAKE TURB AND VORTEX FROM 747 6 MI AHEAD.

Narrative: EXPERIENCE: AIRLINES CAPT INSTRUCTOR 3 YRS. LINE CHK AIRMAN 10 YRS. 19 YRS 727 EXPERIENCE. ATTORNEY, SOME AVIATION LAW. ON APCH RWY 25L FRA NOTICED ON TCASII TFC AHEAD 6 MI. ADVISED BY APCH IT WAS AN ACR 747. WIND AT 4000 FT (OMEGA) 280 DEGS AT 20 KTS. ADVISED 747 WAS ON APCH TO RWY 25R, SURFACE WIND 250 DEGS AT 10 KTS. WITHOUT ANY WARNING, IN IMC, THE 727 ENCOUNTERED WAKE TURB OF SUCH MAGNITUDE THAT WE ROLLED ABOUT 35-40 DEGS WITH FULL AILERON DEFLECTION. I ADDED MAX PWR TO CLB AND FOR WHAT WAS AN UNUSUAL AMOUNT OF TIME THE ACFT DID NOT RESPOND. ONLY ONCE IN THE PAST 30 YRS OF FLYING HAVE I BEEN THIS UNCOMFORTABLE IN A WAKE ENCOUNTER AND THAT WAS 5 MI FROM AN L1011 AT 4000 FT IN NEW YORK. IT APPEARS THAT WITH THE 20 KT WIND THIS TURB SHOULD HAVE DISSIPATED SOMEWHAT AND NOT BEEN A SEVERE ENCOUNTER, ESPECIALLY SINCE WE HAD 5-6 MI SEPARATION! I STRONGLY SUGGEST, FOR SAFETY, WE LOOK CAREFULLY AT OUR 747 SEPARATION STANDARDS.

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.