Narrative:

Encountered moderate turbulence and a slight rolling motion for approximately 5-10 seconds each time during descent between hec and kople intersection at FL240 and 16;000 feet. At the first encounter I slowed approximately 20 KIAS and reduced our rate of descent in an attempt to remain above what I perceived as an aircraft wake. We were aware of an aircraft also on the arrival and observed a target on TCAS approximately 1;400 feet below descending and 12-14 miles ahead. We advised ATC of the turbulence and queried them as to the type of traffic we were following. They confirmed an A320 and stated separation was 17 miles. They advised we would be following that aircraft to the airport and cleared us to slow our descent as desired and also off-set up to 2 miles either side of course. Winds aloft were a left quartering tailwind at 5-7 KTS so I off-set 2 miles left or course. The air was smooth at all other times outside of these encounters and ATC stated there had been no other reports of turbulence in the area. We were in clean configuration; indicating 300 KIAS; and descending 1500 FPM. I expect the A320 was at a similar speed and configuration due to the phase of flight and distance remaining from the airport. I have experienced this type of encounter before; but only while in the close in terminal area; ie downwind vectors; less than 10;000 ft MSL and at distance of 5-8 miles and at or near the same altitude as the aircraft I was following. My solution was to climb approximately 100 ft. As a result of this experience; I usually make a practice of leveling 100 ft high when in this situation; especially if the winds aloft are less than 10-15 KTS. Based on conditions during these encounters; I am extra vigilant to the likelihood of an wake encounter whenever the winds are a quartering tail as I perceive the wake may be being 'held up' by the atmospheric conditions. I recall reading of research that suspects this as well as confirming wake encounters have been recording at 20+ NM. Based on what I see and hear from most airmen. I don't believe enough emphasis is being put on ensuring this information is provided to pilots and controllers during training. Most seem to believe they are safe as long as the 'required' separation is maintained and do not understand that this operation is a 'minimum' distance while not a factor in this instance. I also see a lack of understanding by pilot that they are taking sole responsibility for wake turbulence avoidance and separation when they accept a visual approach as plans to reduce separation in the future grow closer to implementation; it is critical that this information as well as good situational awareness be a part of all flight operations.

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Original NASA ASRS Text

Title: A business jet encountered an A320's wake vortex 17 NM behind and 1400 FT above the traffic descending on an arrival.

Narrative: Encountered moderate turbulence and a slight rolling motion for approximately 5-10 seconds each time during descent between HEC and KOPLE Intersection at FL240 and 16;000 feet. At the first encounter I slowed approximately 20 KIAS and reduced our rate of descent in an attempt to remain above what I perceived as an aircraft wake. We were aware of an aircraft also on the arrival and observed a target on TCAS approximately 1;400 feet below descending and 12-14 miles ahead. We advised ATC of the turbulence and queried them as to the type of traffic we were following. They confirmed an A320 and stated separation was 17 miles. They advised we would be following that aircraft to the airport and cleared us to slow our descent as desired and also off-set up to 2 miles either side of course. Winds aloft were a left quartering tailwind at 5-7 KTS so I off-set 2 miles left or course. The air was smooth at all other times outside of these encounters and ATC stated there had been no other reports of turbulence in the area. We were in clean configuration; indicating 300 KIAS; and descending 1500 FPM. I expect the A320 was at a similar speed and configuration due to the phase of flight and distance remaining from the airport. I have experienced this type of encounter before; but only while in the close in terminal area; IE downwind vectors; less than 10;000 FT MSL and at distance of 5-8 miles and at or near the same altitude as the aircraft I was following. My solution was to climb approximately 100 FT. As a result of this experience; I usually make a practice of leveling 100 FT high when in this situation; especially if the winds aloft are less than 10-15 KTS. Based on conditions during these encounters; I am extra vigilant to the likelihood of an wake encounter whenever the winds are a quartering tail as I perceive the wake may be being 'held up' by the atmospheric conditions. I recall reading of research that suspects this as well as confirming wake encounters have been recording at 20+ NM. Based on what I see and hear from most airmen. I don't believe enough emphasis is being put on ensuring this information is provided to pilots and controllers during training. Most seem to believe they are safe as long as the 'required' separation is maintained and do not understand that this operation is a 'minimum' distance while not a factor in this instance. I also see a lack of understanding by pilot that they are taking sole responsibility for wake turbulence avoidance and separation when they accept a visual approach as plans to reduce separation in the future grow closer to implementation; it is critical that this information as well as good situational awareness be a part of all flight operations.

Data retrieved from NASA's ASRS site as of April 2012 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.