What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Tail flutter wear C77 destination. Reduced power. Flutter ceased. Landed safly. (.19) on October 6, 1997, at 1330 central daylight time (CDT), a Beech G35, N129B, sustained substantial damage during descent when it experienced tail flutter near poplar grove, Illinois. When the pilot reduced power the airplane stopped oscillating. The 14 CFR part 91 flight had departed janesville, Wisconsin, at 1300 CDT and landed at poplar grove airport, poplar grove, Illinois, the intended destination. The pilot and one passenger were not injured. Visual meteorological conditions prevailed and no flight plan had been filed. (.4) the pilot reported that he was cruising at 4,000 feet MSL in clear sky conditions with smooth air, then he initiated a descent. He said that while descending through about 3,200 feet MSL at 185 mph with a 5 degree nose down attitude and 15 degree left turn, the control yoke started oscillating fore and aft about 1/2 inch. The oscillations increased to about 1 inch fore and aft, and the airplane experienced 3 or 4 'solid jolts.' After about 5 seconds, the pilot reduced power, and the vibrations stopped. He continued to his destination and landed uneventfully. According to the pilot operating, the airplane's never exceed airspeed (vne) was 202 mph. The maximum cruise airspeed (vno), was 175 mph. Inspection of the airplane revealed that the aft fuselage received extensive damage between fuselage station (fs) 256.9 and the 233.5 bulkhead. The longerons were bent downward with a permanent 2.5 to 3 inch bend. The left and right side fuselage panels below the stabilizers exhibited 45 degree buckling from the bottom of the fs 256.9 bulkhead to forward of the stabilizer cuffs. The bottom fuselage panel forward of the 256.9 bulkhead had popped rivets and torn skin. There were three creases in the right stabilizer. No pre-existing cracks were found on the longerons. The ruddervators were properly balanced. (-23) on 10/06/97, at 1330 central daylight time aircraft N129B sustained substantial damage during descent when it experienced tail flutter near poplar grove, IL. Engine power was reduced and flutter of tail stopped. Aircraft landed at poplar grove airport. AD notes 87-20-02 rl and 941-20-04 " to prement structural failure of the u tail" were complied with. Rudder were removed and balance found within Beech limits. Cause of tail flutter cou ld not be determined.
As the FAA filed it
TAIL FLUTTER WEAR C77 DESTINATION. REDUCED POWER. FLUTTER CEASED. LANDED SAFLY. (.19) ON OCTOBER 6, 1997, AT 1330 CENTRAL DAYLIGHT TIME (CDT), A BEECH G35, N129B, SUSTAINED SUBSTANTIAL DAMAGE DURING DESCENT WHEN IT EXPERIENCED TAIL FLUTTER NEAR POPLAR GROVE, ILLINOIS. WHEN THE PILOT REDUCED POWER THE AIRPLANE STOPPED OSCILLATING. THE 14 CFR PART 91 FLIGHT HAD DEPARTED JANESVILLE, WISCONSIN, AT 1300 CDT AND LANDED AT POPLAR GROVE AIRPORT, POPLAR GROVE, ILLINOIS, THE INTENDED DESTINATION. THE PILOT AND ONE PASSENGER WERE NOT INJURED. VISUAL METEOROLOGICAL CONDITIONS PREVAILED AND NO FLIGHT PLAN HAD BEEN FILED. (.4) THE PILOT REPORTED THAT HE WAS CRUISING AT 4,000 FEET MSL IN CLEAR SKY CONDITIONS WITH SMOOTH AIR, THEN HE INITIATED A DESCENT. HE SAID THAT WHILE DESCENDING THROUGH ABOUT 3,200 FEET MSL AT 185 MPH WITH A 5 DEGREE NOSE DOWN ATTITUDE AND 15 DEGREE LEFT TURN, THE CONTROL YOKE STARTED OSCILLATING FORE AND AFT ABOUT 1/2 INCH. THE OSCILLATIONS INCREASED TO ABOUT 1 INCH FORE AND AFT, AND THE AIRPLANE EXPERIENCED 3 OR 4 'SOLID JOLTS.' AFTER ABOUT 5 SECONDS, THE PILOT REDUCED POWER, AND THE VIBRATIONS STOPPED. HE CONTINUED TO HIS DESTINATION AND LANDED UNEVENTFULLY. ACCORDING TO THE PILOT OPERATING, THE AIRPLANE'S NEVER EXCEED AIRSPEED (VNE) WAS 202 MPH. THE MAXIMUM CRUISE AIRSPEED (VNO), WAS 175 MPH. INSPECTION OF THE AIRPLANE REVEALED THAT THE AFT FUSELAGE RECEIVED EXTENSIVE DAMAGE BETWEEN FUSELAGE STATION (FS) 256.9 AND THE 233.5 BULKHEAD. THE LONGERONS WERE BENT DOWNWARD WITH A PERMANENT 2.5 TO 3 INCH BEND. THE LEFT AND RIGHT SIDE FUSELAGE PANELS BELOW THE STABILIZERS EXHIBITED 45 DEGREE BUCKLING FROM THE BOTTOM OF THE FS 256.9 BULKHEAD TO FORWARD OF THE STABILIZER CUFFS. THE BOTTOM FUSELAGE PANEL FORWARD OF THE 256.9 BULKHEAD HAD POPPED RIVETS AND TORN SKIN. THERE WERE THREE CREASES IN THE RIGHT STABILIZER. NO PRE-EXISTING CRACKS WERE FOUND ON THE LONGERONS. THE RUDDERVATORS WERE PROPERLY BALANCED. (-23) ON 10/06/97, AT 1330 CENTRAL DAYLIGHT TIME AIRCRAFT N129B SUSTAINED SUBSTANTIAL DAMAGE DURING DESCENT WHEN IT EXPERIENCED TAIL FLUTTER NEAR POPLAR GROVE, IL. ENGINE POWER WAS REDUCED AND FLUTTER OF TAIL STOPPED. AIRCRAFT LANDED AT POPLAR GROVE AIRPORT. AD NOTES 87-20-02 RL AND 941-20-04 " TO PREMENT STRUCTURAL FAILURE OF THE U TAIL" WERE COMPLIED WITH. RUDDER WERE REMOVED AND BALANCE FOUND WITHIN BEECH LIMITS. CAUSE OF TAIL FLUTTER COU LD NOT BE DETERMINED.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.