Narrative:

Aircraft encountered wake turbulence just inside of husky on the canuk 7 arrival. Aircraft had just descended below 10000 ft and the descent and approach check below the line was accomplished. The aircraft rolled rapidly 20 degrees left then 20 degrees right. The first officer (PF) disconnected the autopilot. First officer maintained altitude and offset course to the right to avoid further encounter. Coincidently ATC issued a heading of 360 degrees and descent to 8000 ft. The remainder of the flight was without incident. I called the flight attendant to assess the cabin situation. All passengers strapped in. Flight attendant was collecting trash at the back of the aircraft at the time of the encounter and hit her head against the overhead compartment but was uninjured. An uneventful landing was performed in atl. This is a prime example of accepted risk. I haven't encountered wake turbulence like this for years but if you fly into atl enough and this kind of thing happens. It is good that when we turned on the seat belt sign the passengers respected it; and were all strapped in. Though we can't avoid encounters like this we need better training of crews about the risks factors illustrated here. This was a textbook wake turbulence encounter. During the debrief the flight attendant stated that first she hit her head against one overhead compartment then she hit her head against the other compartment. This is no surprise because first the aircraft rolled rapidly one direction then it rolled rapidly in the other direction. What I said to her and what I would like flight attendant training to emphasis is that wake turbulence encounters often occur in that way and they should expect the aircraft to roll one way then probably back the other way. The other important thing is the fact that most encounters of this type occur below 18000 ft operating into large airports such as atl; cvg; clt; jfk etc (anywhere there are 'heavy' aircraft). What that means is that the 10000 ft bells into a hub are probably the riskiest part of a flight attendant's job. We also might change our procedures regarding the seatbelt sign. My personal rule is that I leave it on below 18000 ft when departing a hub. This is more prudent than turning it off at 10000 ft since there are so many heavies at hubs and that is where the wake risk is the greatest. If we all did this then the flight attendants would know when the risk was lower. Some of them might not get the cart out until then and that should be their choice. The fact is you normally get a wake turbulence encounter like this every several years and it is nearly always while operating into a hub.

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Original NASA ASRS Text

Title: A CRJ-200 ENCOUNTERS WAKE TURBULENCE DURING APPROACH TO ATL.

Narrative: AIRCRAFT ENCOUNTERED WAKE TURBULENCE JUST INSIDE OF HUSKY ON THE CANUK 7 ARRIVAL. AIRCRAFT HAD JUST DESCENDED BELOW 10000 FT AND THE DESCENT AND APPROACH CHECK BELOW THE LINE WAS ACCOMPLISHED. THE AIRCRAFT ROLLED RAPIDLY 20 DEGREES LEFT THEN 20 DEGREES RIGHT. THE FO (PF) DISCONNECTED THE AUTOPILOT. FO MAINTAINED ALTITUDE AND OFFSET COURSE TO THE RIGHT TO AVOID FURTHER ENCOUNTER. COINCIDENTLY ATC ISSUED A HEADING OF 360 DEGS AND DESCENT TO 8000 FT. THE REMAINDER OF THE FLIGHT WAS WITHOUT INCIDENT. I CALLED THE FLT ATTENDANT TO ASSESS THE CABIN SITUATION. ALL PASSENGERS STRAPPED IN. FLT ATTENDANT WAS COLLECTING TRASH AT THE BACK OF THE AIRCRAFT AT THE TIME OF THE ENCOUNTER AND HIT HER HEAD AGAINST THE OVERHEAD COMPARTMENT BUT WAS UNINJURED. AN UNEVENTFUL LANDING WAS PERFORMED IN ATL. THIS IS A PRIME EXAMPLE OF ACCEPTED RISK. I HAVEN'T ENCOUNTERED WAKE TURBULENCE LIKE THIS FOR YEARS BUT IF YOU FLY INTO ATL ENOUGH AND THIS KIND OF THING HAPPENS. IT IS GOOD THAT WHEN WE TURNED ON THE SEAT BELT SIGN THE PASSENGERS RESPECTED IT; AND WERE ALL STRAPPED IN. THOUGH WE CAN'T AVOID ENCOUNTERS LIKE THIS WE NEED BETTER TRAINING OF CREWS ABOUT THE RISKS FACTORS ILLUSTRATED HERE. THIS WAS A TEXTBOOK WAKE TURBULENCE ENCOUNTER. DURING THE DEBRIEF THE FLT ATTENDANT STATED THAT FIRST SHE HIT HER HEAD AGAINST ONE OVERHEAD COMPARTMENT THEN SHE HIT HER HEAD AGAINST THE OTHER COMPARTMENT. THIS IS NO SURPRISE BECAUSE FIRST THE AIRCRAFT ROLLED RAPIDLY ONE DIRECTION THEN IT ROLLED RAPIDLY IN THE OTHER DIRECTION. WHAT I SAID TO HER AND WHAT I WOULD LIKE FLT ATTENDANT TRAINING TO EMPHASIS IS THAT WAKE TURBULENCE ENCOUNTERS OFTEN OCCUR IN THAT WAY AND THEY SHOULD EXPECT THE AIRCRAFT TO ROLL ONE WAY THEN PROBABLY BACK THE OTHER WAY. THE OTHER IMPORTANT THING IS THE FACT THAT MOST ENCOUNTERS OF THIS TYPE OCCUR BELOW 18000 FT OPERATING INTO LARGE ARPTS SUCH AS ATL; CVG; CLT; JFK ETC (ANYWHERE THERE ARE 'HEAVY' AIRCRAFT). WHAT THAT MEANS IS THAT THE 10000 FT BELLS INTO A HUB ARE PROBABLY THE RISKIEST PART OF A FLT ATTENDANT'S JOB. WE ALSO MIGHT CHANGE OUR PROCEDURES REGARDING THE SEATBELT SIGN. MY PERSONAL RULE IS THAT I LEAVE IT ON BELOW 18000 FT WHEN DEPARTING A HUB. THIS IS MORE PRUDENT THAN TURNING IT OFF AT 10000 FT SINCE THERE ARE SO MANY HEAVIES AT HUBS AND THAT IS WHERE THE WAKE RISK IS THE GREATEST. IF WE ALL DID THIS THEN THE FLT ATTENDANTS WOULD KNOW WHEN THE RISK WAS LOWER. SOME OF THEM MIGHT NOT GET THE CART OUT UNTIL THEN AND THAT SHOULD BE THEIR CHOICE. THE FACT IS YOU NORMALLY GET A WAKE TURBULENCE ENCOUNTER LIKE THIS EVERY SEVERAL YEARS AND IT IS NEARLY ALWAYS WHILE OPERATING INTO A HUB.

Data retrieved from NASA's ASRS site as of May 2009 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.