Narrative:

On jun/fri/95, I was cruising in a bae 125-1000 (hawker 1000), en route from mdw to teb. At approximately XA20Z, in the vicinity of the wilkes-barre VOR (lvz), I was given a descent clearance by the ZNY sector controller. I initiated the descent from cruise altitude of FL330 with the autoplt engaged. Passing through approximately FL320, the aircraft made an abrupt and violent roll to the left to almost 90 degrees. I instinctively responded to the abrupt roll and grasped the yoke to regain control, attempting to roll back to level. In the process of grasping the yoke and rolling back to level attitude, I applied sufficient force (approximately 80 pounds) to disconnect the pilot's and copilot's aileron interconnect system. Parenthetically, this system on the hawker is designed so that one pilot or the other might regain respective control of the aircraft for independent aileron operation in the event there should ever be a mechanical jam or obstruction between the 2 control yokes -- not the situation here. I mention this aspect of the incident only to emphasize how sudden and unexpected the roll described above was. Further, because of the characteristics of the roll and the rate of roll, I immediately suspected a heavy aircraft in our close proximity. After regaining a little composure, I asked the ATC controller if we were behind a heavy aircraft, and he responded, 'yes, about 12 mi behind a B767.' we reviewed the abnormal procedures checklist for the aileron disconnect and followed its procedure to continue with the autoplt off. Except for the reduced aileron effectiveness caused by the aileron disconnect, we landed uneventfully about 30 mins later. I spoke with mr X, ZNY after I got on the ground. He said that 12 mi for an aircraft like a hawker behind a heavy is well within their regulatory separation criteria. However, referred the matter to mr Y, in the ZNY's quality assurance department. About 3 days later, mr Y called me back after he had reviewed the tape of the incident. He asked me a few more questions about the incident and expressed his genuine concern about the hazards of wake turbulence. He also stated that a mr Z would be following up on the incident, and at mr Y request, I sent a copy of my company report to mr Z. To this date I have heard nothing further. As we discussed, 12 mi at cruise altitude should be plenty of separation. However, at our relative cruise speeds, I would estimate that 12 mi was not much more than 90 seconds since my own ground speed was approximately 460 to 480 KTS. It is well known that wake turbulence can linger for quite some time, although one would probably not expect it at higher altitudes. Nevertheless, it did happen in this apparently rare instance. It therefore seems to me that it's time to take another look at the wake turbulence phenomena (in a cruise situation as well as in the terminal area) of the newer heavy's like the B757 and the B767, as well as others. My greatest concern is that if it happened to me, it can happen again to someone else who might not be as lucky in regaining control of his aircraft. Callback conversation with reporter revealed the following information: the reporter stated he was flying the newly designated BA10. He suspects this is significant if the controllers think a BA10 is a bigger airplane, and, for that reason, do not provide as much spacing behind heavier aircraft. The controller may have over flown this B767 and dumped the B767 along his route ahead of him on the wilkes- barre 124 radial. The B767 was perhaps on the arrival to kennedy. The reporter on the arrival to teterboro. Both going over wilkes-barre on the same radial for their respective arrival rtes. The reporter stated the event was over within 3 seconds, but, during that time the aircraft rolled 80-90 degrees. When he first grabbed the wheel the thought occurred the autoplt had given a hard over. He applied aileron to oppose it but the aileron was neutral and over riding the autoplt so abruptly caused the left aileron to disconnect from the right aileron. The reporter reemphasized the suddenness of the encounter. Then, hence forth, only the left aileron moved with aileron application. He disconnected the autoplt, extended spdbrakes and descended to a lower altitude. Whenhe realized he was with reduced aileron effectiveness he completed the abnormal checklist, flew a wider pattern, and landed without further incident.

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Original NASA ASRS Text

Title: A BOEING 767 WAKE THROWS RPTR, IN A HAWKER 1000 12 MI BEHIND, INTO AN 80-90 DEG BANK AT 32000 FT.

Narrative: ON JUN/FRI/95, I WAS CRUISING IN A BAE 125-1000 (HAWKER 1000), ENRTE FROM MDW TO TEB. AT APPROX XA20Z, IN THE VICINITY OF THE WILKES-BARRE VOR (LVZ), I WAS GIVEN A DSCNT CLRNC BY THE ZNY SECTOR CTLR. I INITIATED THE DSCNT FROM CRUISE ALT OF FL330 WITH THE AUTOPLT ENGAGED. PASSING THROUGH APPROX FL320, THE ACFT MADE AN ABRUPT AND VIOLENT ROLL TO THE L TO ALMOST 90 DEGS. I INSTINCTIVELY RESPONDED TO THE ABRUPT ROLL AND GRASPED THE YOKE TO REGAIN CTL, ATTEMPTING TO ROLL BACK TO LEVEL. IN THE PROCESS OF GRASPING THE YOKE AND ROLLING BACK TO LEVEL ATTITUDE, I APPLIED SUFFICIENT FORCE (APPROX 80 LBS) TO DISCONNECT THE PLT'S AND COPLT'S AILERON INTERCONNECT SYS. PARENTHETICALLY, THIS SYS ON THE HAWKER IS DESIGNED SO THAT ONE PLT OR THE OTHER MIGHT REGAIN RESPECTIVE CTL OF THE ACFT FOR INDEPENDENT AILERON OP IN THE EVENT THERE SHOULD EVER BE A MECHANICAL JAM OR OBSTRUCTION BTWN THE 2 CTL YOKES -- NOT THE SIT HERE. I MENTION THIS ASPECT OF THE INCIDENT ONLY TO EMPHASIZE HOW SUDDEN AND UNEXPECTED THE ROLL DESCRIBED ABOVE WAS. FURTHER, BECAUSE OF THE CHARACTERISTICS OF THE ROLL AND THE RATE OF ROLL, I IMMEDIATELY SUSPECTED A HVY ACFT IN OUR CLOSE PROX. AFTER REGAINING A LITTLE COMPOSURE, I ASKED THE ATC CTLR IF WE WERE BEHIND A HVY ACFT, AND HE RESPONDED, 'YES, ABOUT 12 MI BEHIND A B767.' WE REVIEWED THE ABNORMAL PROCS CHKLIST FOR THE AILERON DISCONNECT AND FOLLOWED ITS PROC TO CONTINUE WITH THE AUTOPLT OFF. EXCEPT FOR THE REDUCED AILERON EFFECTIVENESS CAUSED BY THE AILERON DISCONNECT, WE LANDED UNEVENTFULLY ABOUT 30 MINS LATER. I SPOKE WITH MR X, ZNY AFTER I GOT ON THE GND. HE SAID THAT 12 MI FOR AN ACFT LIKE A HAWKER BEHIND A HVY IS WELL WITHIN THEIR REGULATORY SEPARATION CRITERIA. HOWEVER, REFERRED THE MATTER TO MR Y, IN THE ZNY'S QUALITY ASSURANCE DEPT. ABOUT 3 DAYS LATER, MR Y CALLED ME BACK AFTER HE HAD REVIEWED THE TAPE OF THE INCIDENT. HE ASKED ME A FEW MORE QUESTIONS ABOUT THE INCIDENT AND EXPRESSED HIS GENUINE CONCERN ABOUT THE HAZARDS OF WAKE TURB. HE ALSO STATED THAT A MR Z WOULD BE FOLLOWING UP ON THE INCIDENT, AND AT MR Y REQUEST, I SENT A COPY OF MY COMPANY RPT TO MR Z. TO THIS DATE I HAVE HEARD NOTHING FURTHER. AS WE DISCUSSED, 12 MI AT CRUISE ALT SHOULD BE PLENTY OF SEPARATION. HOWEVER, AT OUR RELATIVE CRUISE SPDS, I WOULD ESTIMATE THAT 12 MI WAS NOT MUCH MORE THAN 90 SECONDS SINCE MY OWN GND SPD WAS APPROX 460 TO 480 KTS. IT IS WELL KNOWN THAT WAKE TURB CAN LINGER FOR QUITE SOME TIME, ALTHOUGH ONE WOULD PROBABLY NOT EXPECT IT AT HIGHER ALTS. NEVERTHELESS, IT DID HAPPEN IN THIS APPARENTLY RARE INSTANCE. IT THEREFORE SEEMS TO ME THAT IT'S TIME TO TAKE ANOTHER LOOK AT THE WAKE TURB PHENOMENA (IN A CRUISE SIT AS WELL AS IN THE TERMINAL AREA) OF THE NEWER HVY'S LIKE THE B757 AND THE B767, AS WELL AS OTHERS. MY GREATEST CONCERN IS THAT IF IT HAPPENED TO ME, IT CAN HAPPEN AGAIN TO SOMEONE ELSE WHO MIGHT NOT BE AS LUCKY IN REGAINING CTL OF HIS ACFT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED HE WAS FLYING THE NEWLY DESIGNATED BA10. HE SUSPECTS THIS IS SIGNIFICANT IF THE CTLRS THINK A BA10 IS A BIGGER AIRPLANE, AND, FOR THAT REASON, DO NOT PROVIDE AS MUCH SPACING BEHIND HEAVIER ACFT. THE CTLR MAY HAVE OVER FLOWN THIS B767 AND DUMPED THE B767 ALONG HIS RTE AHEAD OF HIM ON THE WILKES- BARRE 124 RADIAL. THE B767 WAS PERHAPS ON THE ARR TO KENNEDY. THE RPTR ON THE ARR TO TETERBORO. BOTH GOING OVER WILKES-BARRE ON THE SAME RADIAL FOR THEIR RESPECTIVE ARR RTES. THE RPTR STATED THE EVENT WAS OVER WITHIN 3 SECONDS, BUT, DURING THAT TIME THE ACFT ROLLED 80-90 DEGS. WHEN HE FIRST GRABBED THE WHEEL THE THOUGHT OCCURRED THE AUTOPLT HAD GIVEN A HARD OVER. HE APPLIED AILERON TO OPPOSE IT BUT THE AILERON WAS NEUTRAL AND OVER RIDING THE AUTOPLT SO ABRUPTLY CAUSED THE L AILERON TO DISCONNECT FROM THE R AILERON. THE RPTR REEMPHASIZED THE SUDDENNESS OF THE ENCOUNTER. THEN, HENCE FORTH, ONLY THE L AILERON MOVED WITH AILERON APPLICATION. HE DISCONNECTED THE AUTOPLT, EXTENDED SPDBRAKES AND DSNDED TO A LOWER ALT. WHENHE REALIZED HE WAS WITH REDUCED AILERON EFFECTIVENESS HE COMPLETED THE ABNORMAL CHKLIST, FLEW A WIDER PATTERN, AND LANDED WITHOUT FURTHER INCIDENT.

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.