A CLBING FK100 FLC ENCOUNTERS WAKE TURB 300 FT BELOW A B767-200 AND 17 MI IN TRAIL WITH CALM WINDS ALOFT 85 MI W OF LIT.

Date: 2000-08 · Aircraft: Fokker 100 · Phase: climb

Anomalies: inflight-event-encounter-wake-vortex-encounter|inflight-event-encounter-loss-of-aircraft-control

Synopsis

A CLBING FK100 FLC ENCOUNTERS WAKE TURB 300 FT BELOW A B767-200 AND 17 MI IN TRAIL WITH CALM WINDS ALOFT 85 MI W OF LIT.

Narrative

LOCATION: APPROX 85 MI W OF LIT ON DALL5 DEP PROC. JUST PRIOR TO LEVELING OFF AT FL330; AT ABOUT FL327; WE ENCOUNTERED MODERATE TO SEVERE RAPID AND INSTANTANEOUS ROLL REVERSALS AND TURB. WE WERE IN PERFECTLY SMOOTH AIR WITH NO (ZERO) WIND AND NOT ANYWHERE NEAR THE JETSTREAM AS FORECASTED. WE WERE ABOUT 17 NM IN TRAIL WITH A HVY B767 THAT HAD PREVIOUSLY OVERFLOWN US IN HIS AFTER CLBOUT AND SPD CAPABILITY. WE IMMEDIATELY REQUESTED AND RECEIVED CLRNC TO FL290. ALL SYS AND CTLS WERE NORMAL. WE STRONGLY AND OBVIOUSLY SUSPECT THAT IN THE CALM AIR; THIS HVY ACFT'S VORTICES DO NOT DSND VERY FAST -- IF AT ALL -- AND AT 17 MI IN TRAIL ARE ONLY ABOUT 1 1/2 MINS BEHIND. I RECOMMEND THAT ALL OPERATOR'S MANUALS BE UPDATED TO REFLECT THIS WAKE/VORTEX BEHAVIOR AT ALT IN SMOOTH AIR; WHICH IS VERY SIMILAR TO THEIR BEHAVIOR IN SMOOTH AIR AT LOW ALT WITH ANTICIPATED SEPARATION. WROTE UP THE ENCOUNTER IN THE LOGBOOK; AND THE ACFT WAS INSPECTED AND FOUND AIRWORTHY. NO INJURIES RESULTED TO PAX OR CREW AS THE FASTEN SEATBELT SIGN HAD JUST BEEN TURNED OFF AND THE FLT ATTENDANTS RESPONDED QUICKLY. OF COURSE; DURING THE ENCOUNTER; THE SEATBELT SIGN WAS IMMEDIATELY TURNED BACK ON. SUPPLEMENTAL INFO FROM ACN 482222: I BEGAN A SMOOTH DSCNT AND THE RIDE GREATLY IMPROVED PASSING APPROX FL315. WE WERE IN CLR AIR AT THE TIME AND THE FMS WINDS WERE CALM. CAPT NOTIFIED DISPATCHER. THE AIR MAY HAVE SMOOTHED OUT IF WE HAD WAITED A BIT; BUT THEN AGAIN IT MAY HAVE GOTTEN A LOT WORSE. IT WAS TIME TO GET OUT OF THERE NOW.

Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.