Narrative:

ILS approach and landing on runway 4 in bos. Approach control let us down late and gave us a late speed reduction. We had trouble getting down and slowing down -- more than usual. Wind at airport was reported as 040 degrees at 8 KTS. We were following a B767 by about 6 mi. I told the captain that I would fly 1/2 to 1 DOT above GS for wake turbulence protection and did. We were given all the proper wake turbulence and separation warnings by both the approach and tower controllers. Once established on the approach as planned, I found I was carrying much less power than usual -- even staying 1 DOT high. At about 200 ft we began to be buffeted. The airplane yawed and banked to the left. I tried to correct with aileron and rudder. When I reached full right aileron and 3/4 right rudder, I said, 'I'm going around' and pulled back on the yoke, applied thrust, and began the go around procedure. As soon as I pulled up, I regained complete control. The captain followed through with all the correct procedures and backed me up 100 percent. After he told the tower we were going around they gave us a heading, an altitude, and switched us to departure. Departure control asked us the reason for the go around and we told them wake turbulence. The word got back to the approach controller who apparently got word from an aircraft that the wind at the OM for runway 4 was 210 degrees at 40 KTS. Now it made sense! The aloft tailwind caused our approach difficulties and it blew the B767's wakes forward into our glide path. Bos switched the approach runway. I had never before thought about the effect of a tailwind on wakes. I do now! One side note: our MD80's do not have the gear to give us accurate wind information (except at cruise). I cannot wait to get on a higher tech airplane. Of course, I should have recognized the signs. Callback conversation with reporter revealed the following information: this flight crew was flying an MD81 when they encountered an usual windshear situation that had a strong tailwind at OM altitude (about 3000 ft) and a headwind on the surface. The strong tailwind pushed the B767's wake forward as it settled toward the surface. This forward movement caused the MD81 crew to intercept the wake even though they were flying above the GS. The reporter said that this was the strongest wake effect that he had encountered yet. As he started to reach full deployment of his roll and yaw controls, he noted that he was no longer aligned with the runway. The wake had pushed the aircraft to the left edge and at that point he announced that he was going around. The next approach was normal. Shortly after landing the tower changed runways.

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Original NASA ASRS Text

Title: ACR MD81 CREW ENCOUNTERS THE WAKE OF A B767 ON FINAL APCH TO BOS RWY 4. A VERY STRONG TAILWIND AT OM ALT PUSHED THE WAKE TOWARD THE RWY AND DEFEATED THE FLC'S AVOIDANCE TECHNIQUES. THE MD81 CREW PERFORMED A GAR.

Narrative: ILS APCH AND LNDG ON RWY 4 IN BOS. APCH CTL LET US DOWN LATE AND GAVE US A LATE SPD REDUCTION. WE HAD TROUBLE GETTING DOWN AND SLOWING DOWN -- MORE THAN USUAL. WIND AT ARPT WAS RPTED AS 040 DEGS AT 8 KTS. WE WERE FOLLOWING A B767 BY ABOUT 6 MI. I TOLD THE CAPT THAT I WOULD FLY 1/2 TO 1 DOT ABOVE GS FOR WAKE TURB PROTECTION AND DID. WE WERE GIVEN ALL THE PROPER WAKE TURB AND SEPARATION WARNINGS BY BOTH THE APCH AND TWR CTLRS. ONCE ESTABLISHED ON THE APCH AS PLANNED, I FOUND I WAS CARRYING MUCH LESS PWR THAN USUAL -- EVEN STAYING 1 DOT HIGH. AT ABOUT 200 FT WE BEGAN TO BE BUFFETED. THE AIRPLANE YAWED AND BANKED TO THE L. I TRIED TO CORRECT WITH AILERON AND RUDDER. WHEN I REACHED FULL R AILERON AND 3/4 R RUDDER, I SAID, 'I'M GOING AROUND' AND PULLED BACK ON THE YOKE, APPLIED THRUST, AND BEGAN THE GAR PROC. AS SOON AS I PULLED UP, I REGAINED COMPLETE CTL. THE CAPT FOLLOWED THROUGH WITH ALL THE CORRECT PROCS AND BACKED ME UP 100 PERCENT. AFTER HE TOLD THE TWR WE WERE GOING AROUND THEY GAVE US A HDG, AN ALT, AND SWITCHED US TO DEP. DEP CTL ASKED US THE REASON FOR THE GAR AND WE TOLD THEM WAKE TURB. THE WORD GOT BACK TO THE APCH CTLR WHO APPARENTLY GOT WORD FROM AN ACFT THAT THE WIND AT THE OM FOR RWY 4 WAS 210 DEGS AT 40 KTS. NOW IT MADE SENSE! THE ALOFT TAILWIND CAUSED OUR APCH DIFFICULTIES AND IT BLEW THE B767'S WAKES FORWARD INTO OUR GLIDE PATH. BOS SWITCHED THE APCH RWY. I HAD NEVER BEFORE THOUGHT ABOUT THE EFFECT OF A TAILWIND ON WAKES. I DO NOW! ONE SIDE NOTE: OUR MD80'S DO NOT HAVE THE GEAR TO GIVE US ACCURATE WIND INFO (EXCEPT AT CRUISE). I CANNOT WAIT TO GET ON A HIGHER TECH AIRPLANE. OF COURSE, I SHOULD HAVE RECOGNIZED THE SIGNS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THIS FLC WAS FLYING AN MD81 WHEN THEY ENCOUNTERED AN USUAL WINDSHEAR SIT THAT HAD A STRONG TAILWIND AT OM ALT (ABOUT 3000 FT) AND A HEADWIND ON THE SURFACE. THE STRONG TAILWIND PUSHED THE B767'S WAKE FORWARD AS IT SETTLED TOWARD THE SURFACE. THIS FORWARD MOVEMENT CAUSED THE MD81 CREW TO INTERCEPT THE WAKE EVEN THOUGH THEY WERE FLYING ABOVE THE GS. THE RPTR SAID THAT THIS WAS THE STRONGEST WAKE EFFECT THAT HE HAD ENCOUNTERED YET. AS HE STARTED TO REACH FULL DEPLOYMENT OF HIS ROLL AND YAW CTLS, HE NOTED THAT HE WAS NO LONGER ALIGNED WITH THE RWY. THE WAKE HAD PUSHED THE ACFT TO THE L EDGE AND AT THAT POINT HE ANNOUNCED THAT HE WAS GOING AROUND. THE NEXT APCH WAS NORMAL. SHORTLY AFTER LNDG THE TWR CHANGED RWYS.

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.