# NTSB MKC90FA107: Beech A35, N511B, Washington, MO, May 14, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Field investigation · Final report
- Date: May 14, 1990, 14:00 local (19:00 UTC)
- Place: Washington, MO
- Coordinates: 38.549678, -91.010551 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.5497&lon=-91.0106&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report March 9, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 34884
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC90FA107
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/34884/pdf
- Page: https://openairdocs.org/ntsb/MKC90FA107

## Probable cause

IMPROPER STATIC BALANCE OF THE RUDDERVATORS FOLLOWING REBUILDING/REPAINTING, WHICH RESULTED IN EMPENNAGE FLUTTER.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, descent
  - maintenance,balancing - improper, copilot/second pilot (cause)
  - flight control,ruddervator - improper (cause)
  - flight control,ruddervator - flutter
  - fuselage,bulkhead - cracked
  - fuselage,skin - buckled

## Analysis

FLUTTER OF THE EMPENNAGE OCCURRED DURING FLIGHT IN SMOOTH AIR, RESULTING IN SUBSTANTIAL DAMAGE TO THE AFT FUSELAGE & BULKHEADS NEAR THE RUDDERVATOR ATTACHMENT POINTS.  POST-ACCIDENT TESTS DISCLOSED THE STATIC BALANCE OF BOTH RUDDERVATORS TO BE EXCESSIVELY TAIL-HEAVY.  THERE WAS EVIDENCE THAT THE RUDDERVATOR SURFACES HAD LAST BEEN PAINTED, WHILE STILL ATTACHED TO THE AIRPLANE.  THICKNESS OF THE PRIMER & PAINT EXCEEDED THE MANUFACTURER'S FACTORY ACCEPTANCE CRITERIA.

## Aircraft

- Registration: [N511B](https://openairdocs.org/deregistered/N511B-1995-01-17), registration cancelled 1995-01-17, S/N D1534 (OpenAirDocs)
- Reported make and model: BEECH A35
- Registry model: [Beech A35](https://openairdocs.org/model/beech-a35) (registry code 1151504) (OpenAirDocs)
- Category: Airplane
- Serial number: D-1532
- Airframe hours: 3840
- Engines: CONTINENTAL E-185-8 185 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Edw. Winchester & John Bassett
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, April 6, 1990, 13 hours before
- Departed: AUGUSTA, KS
- Destination: MO49, WASHINGTON, MO

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 1,030 total, 150 in this make and model, 845 as pilot in command, 13 in the last 90 days, 11 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 25 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 10 °F

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19900514016559A](https://openairdocs.org/incident/19900514016559A), May 14, 1990: Beech A35, Washington, MO, Substantial damage. Tail flutter inflight. Landed safe. Aft fuselage and stabilizers damaged. Worn rivets and heavy paint on ruddervator

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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.