# Accident 19971006038969A: Beech G35, Belvidere, IL, October 6, 1997

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: October 6, 1997, 13:30 local time
- Place: Belvidere, IL
- Airport: Belvidere Ltd Airport
- Damage: Substantial damage
- Phase of flight: Descent
- Operating rules: General operating rules (Part 91)
- Location: 42.3598° N, 88.8194° W: From the FAA, an estimate near the named town, within about 3 miles
- Nearby events: https://openairdocs.org/map.md?lat=42.3598&lon=-88.8194&mi=10
- Aircraft: N129B (not matched to a registry record)
- Reported make and model: BEECH G35
- People aboard: 2
- Fatal injuries: 0
- NTSB investigation: [NTSB CHI98FA017](https://openairdocs.org/ntsb/CHI98FA017) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/19971006038969A

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

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.

## The NTSB's investigation of this event (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB CHI98FA017](https://openairdocs.org/ntsb/CHI98FA017), Oct 6, 1997: Beech G35 (N129B), Poplar Grove, IL, substantial damage. Probable cause: flutter for an undetermined reason, which resulted in structural damage to the aft fuselage.

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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