Medium large transport following a newer medium large transport type encountered wake turbulence.

Attributes
ACN	119921
Time
Date	198908
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : cvg
State Reference	OH
Altitude	agl bound lower : 250 agl bound upper : 250
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : cvg
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach landing other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 120 flight time total : 2000 flight time type : 150
ASRS Report	119921
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude other anomaly other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : regained aircraft control
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

At 250' AGL on the CAT ii ILS runway 36 approach to cvg, we encountered mod wake turbulence from a widebody transport that had landed in front of us. Although we had legal IFR separation, a large power increase and significant control wheel input was required to maintain a stabilized flight path. If the runway environment had not been in sight, a go around would have been required. The tower controller had warned us of possible wake turbulence at 1 NM on the approach. This warning also contributed to a safe landing rather than a missed approach. Recommend increasing required IFR separation behind widebody transport aircraft to 5 NM vice the present 3 NM to preclude recurrence of this wake turbulence hazard.

Original NASA ASRS Text

Title: MLG FOLLOWING A NEWER MLG TYPE ENCOUNTERED WAKE TURBULENCE.

Narrative: AT 250' AGL ON THE CAT II ILS RWY 36 APCH TO CVG, WE ENCOUNTERED MOD WAKE TURBULENCE FROM A WDB THAT HAD LANDED IN FRONT OF US. ALTHOUGH WE HAD LEGAL IFR SEPARATION, A LARGE POWER INCREASE AND SIGNIFICANT CONTROL WHEEL INPUT WAS REQUIRED TO MAINTAIN A STABILIZED FLT PATH. IF THE RWY ENVIRONMENT HAD NOT BEEN IN SIGHT, A GO AROUND WOULD HAVE BEEN REQUIRED. THE TWR CTLR HAD WARNED US OF POSSIBLE WAKE TURBULENCE AT 1 NM ON THE APCH. THIS WARNING ALSO CONTRIBUTED TO A SAFE LNDG RATHER THAN A MISSED APCH. RECOMMEND INCREASING REQUIRED IFR SEPARATION BEHIND WDB ACFT TO 5 NM VICE THE PRESENT 3 NM TO PRECLUDE RECURRENCE OF THIS WAKE TURBULENCE HAZARD.

Data retrieved from NASA's ASRS site as of August 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.