AN ARR B727-200 GETS TOO CLOSE TO A TSTM NEAR FINAL APCH AND EXPERIENCES WINDSHEAR AND SEVERE TURB ON FINAL. PART OF THE TURB WAS DURING THE MISSED APCH. DURING THIS EVENT THE CAPT UNKNOWINGLY OVERBOOSTED THE ENGS. THE FLT WENT TO BHM; AL; AND THEN LATER RETURNED TO ATL; WITH THE OVER BOOST NOT KNOWN UNTIL LATER.

Narrative

WE WERE ON VECTORS FOR RWY 9R AT ATL. THERE WERE TSTMS IN AND AROUND THE ATLANTA AREA. WE INTERCEPTED THE LOC AT 3500 FT MSL WITH NO RAIN OR TURB PRESENT. THERE WERE 2 ACFT AHEAD OF US AND THE FIRST ONE TO LAND RPTED AIRSPD FLUCTUATIONS OF 10 OR 15 KTS. THE ACFT AHEAD OF US EXECUTED A GAR SHORTLY THEREAFTER. AS WE CONTINUED DOWN THE GS; WE ENCOUNTERED MODERATE TURB AT 2800 FT MSL WITH A JUMP IN AIRSPD FROM 160 KIAS TO 200 KIAS. THE CAPT INITIATED A GAR BY PUSHING UP THE THROTTLES TO JUST ABOVE GAR PWR. I PULLED THE THROTTLES BACK TO GAR PWR SETTINGS. AT ABOUT THAT TIME WE GOT THE WINDSHEAR ADVISORY AND GUIDANCE. THE CAPT ADVANCED THE PWR LEVERS AGAIN. I WAS UNABLE TO SEE THE EPR READING DUE TO THE MODERATE TO SEVERE TURB WE ENCOUNTERED DURING THE GAR. I KEPT MY EYE ON THE EXHAUST GAS TEMP GAUGE AND NEVER SAW IT EXCEED ANY LIMITATIONS. IT TOOK SOME TIME TO CONTACT APCH CTL; AS THEY WERE GIVING INSTRUCTIONS TO THE ACFT AHEAD OF US. THE CAPT MADE A CLBOUT STRAIGHT AHEAD TO AVOID CONFLICTING WITH THE TFC AHEAD OF US. ONCE WE MADE CONTACT; HE GAVE US A TURN TO 180 DEGS AND 3500 FT MSL. DUE TO THE POSITIVE PERFORMANCE; WINDSHEAR; AND OUR HIGH PWR SETTING; WE ADVISED THEM WE WERE ALREADY THROUGH THAT ALT. THEY TOLD US TO DSND WHEN ABLE. ABOUT THAT SAME TIME; THE CAPT PULLED THE PWR BACK. IT HAD BEEN UP ABOVE GAR EPR FOR 5-8 SECONDS. I CHKED ALL ENG INSTS AS WE LEVELED OFF AND EXITED THE WINDSHEAR -- ALL APPEARED TO BE NORMAL. WE DIVERTED TO BHM WITHOUT FURTHER INCIDENT. WE WERE ON THE GND IN BHM FOR 1+45 BEFORE RETURNING TO ATL FOR AN UNEVENTFUL LNDG. LATER; MAINT PULLED THE TAPES ON THE ENGS AND DISCOVERED THAT THE ENGS HAD INDEED EXCEEDED THEIR LIMITS FOR A FEW SECONDS REACHING 700 DEGS C WITH A MAX ACCELERATION LIMIT OF 630 DEGS C. AT NO TIME PRIOR TO OUR RETURN TO ATL DID WE EXPECT THAT THE ENGS HAD BEEN OVERBOOSTED. SUPPLEMENTAL INFO FROM ACN 398829: WHEN THE TURB GOT WORSE; I PUSHED THE PWR AHEAD AGAIN. THE SO SAID THAT PWR DID NOT EXCEED LIMITS. BECAUSE OF THE HOLDING WE DID PRIOR TO APCH; OUR FUEL WAS GETTING LOW; SO WE DIVERTED TO BIRMINGHAM. THE MAIN CONTRIBUTING FACTOR FOR THIS SIT I BELIEVE WAS THAT OUR BASIC RADAR ONLY ALLOWED US TO ESTIMATE THE POS OF THE WX IN RELATION TO THE FIELD. HAD WE HAD RADAR OVERLAY OF OUR APCH COURSE DEPICTED ON OUR HSI WE WOULD HAVE KNOWN EXACTLY WHERE THE WX WAS. THIS EXPERIENCE WILL MAKE ME GIVE MORE BERTH TO ANY FUTURE WX I ENCOUNTER. SUPPLEMENTAL INFO FROM ACN 398649: I GOT THROUGH TO TWR WHO TOLD US TO CLB TO 3500 FT. AT THIS TIME WE WERE AT APPROX 4100 FT AND EXITING THE STORM CLOUD. I THINK THAT ANY WARNING LIGHT THAT WOULD COME ON WHEN ENGS EXCEED NORMAL PARAMETERS AND ALERT THE CREW WOULD BE VERY HELPFUL -- ESPECIALLY AT NIGHT AND IN TURB.