Wake turbulence encounter during arrival in area.

Attributes
ACN	307445
Time
Date	199506
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : shb
State Reference	IN
Altitude	msl bound lower : 17000 msl bound upper : 17000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Challenger CL604
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other descent other
Route In Use	arrival star : star enroute airway : zid
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise other descent other
Route In Use	arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 270 flight time total : 12500 flight time type : 1900
ASRS Report	307445
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	inflight encounter other
Independent Detector	other flight crewa
Resolutory Action	flight crew : regained aircraft control flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

12 NM in trail with B727 same altitude same direction at 17000 ft 400 TAS encountered wake from preceding aircraft 10-15 degree rolls very quick. Associated light turbulence. Callback conversation with reporter revealed the following information: this callback is part of the structured callback questionnaire for wake turbulence. Reporter was mostly surprised that the wake turbulence was at same altitude that he was at. The aircraft ahead of him at the same altitude causing the wake, at 12 mi distance, should have given enough time for the wake to descend. The bank rolled up to 25 degrees with the autoplt engaged. Total duration was around 5 seconds. Although duration was short, it seemed like a long time to the flight crew since aircraft was responding to flight control inputs from the autoplt. Reporter doesn't believe he would do anything different in the future under the same circumstances as it is so difficult to predict where wake turbulence might be encountered.

Original NASA ASRS Text

Title: WAKE TURB ENCOUNTER DURING ARR IN AREA.

Narrative: 12 NM IN TRAIL WITH B727 SAME ALT SAME DIRECTION AT 17000 FT 400 TAS ENCOUNTERED WAKE FROM PRECEDING ACFT 10-15 DEG ROLLS VERY QUICK. ASSOCIATED LIGHT TURB. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THIS CALLBACK IS PART OF THE STRUCTURED CALLBACK QUESTIONNAIRE FOR WAKE TURB. RPTR WAS MOSTLY SURPRISED THAT THE WAKE TURB WAS AT SAME ALT THAT HE WAS AT. THE ACFT AHEAD OF HIM AT THE SAME ALT CAUSING THE WAKE, AT 12 MI DISTANCE, SHOULD HAVE GIVEN ENOUGH TIME FOR THE WAKE TO DSND. THE BANK ROLLED UP TO 25 DEGS WITH THE AUTOPLT ENGAGED. TOTAL DURATION WAS AROUND 5 SECONDS. ALTHOUGH DURATION WAS SHORT, IT SEEMED LIKE A LONG TIME TO THE FLC SINCE ACFT WAS RESPONDING TO FLT CTL INPUTS FROM THE AUTOPLT. RPTR DOESN'T BELIEVE HE WOULD DO ANYTHING DIFFERENT IN THE FUTURE UNDER THE SAME CIRCUMSTANCES AS IT IS SO DIFFICULT TO PREDICT WHERE WAKE TURB MIGHT BE ENCOUNTERED.

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.