# NTSB FTW91FA080: Beech V35B, N9435Q, Manor, TX, May 16, 1991

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: May 16, 1991, 10:20 local (15:20 UTC)
- Place: Manor, TX
- Coordinates: 30.3404, -97.55088 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=30.3404&lon=-97.5509&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 4 fatal
- Status: Completed, report December 4, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 23260
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW91FA080
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/23260/pdf
- Page: https://openairdocs.org/ntsb/FTW91FA080

## Probable cause

THE PILOT'S OPERATION OF THE AIRCRAFT AT A GROSS WEIGHT AND CENTER OF GRAVITY  WHICH EXCEEDED THE CERTIFICATED OPERATING LIMITATIONS, RESULTING IN LOSS OF CONTROL AND STRUCTURAL OVERLOAD.  TURBULENCE WAS A RELATED FACTOR.

## Analysis

THE PLT LOST CTL OF THE ACFT IN IFR CONDS AS THE PLANE WAS DSCNDG THRU ABT 6000' MSL, IN AN AREA OF CONVECTIVE ACTIVITY WITH MODERATE TO SEVERE TURBC & UP/DOWN DRAFTS.  BOTH WINGS SEPD FM THE ACFT & WRECKAGE WAS SCATTERED OVER AN AREA OF APRX 1.5 MI.  CALCULATIONS SHOWED THAT AT THE TIME OF THE ACDNT, THE ACFT'S GROSS WT WAS 29 LBS OVER ITS MAX LIMIT, AND THE CENTER-OF-GRAVITY (CG) WAS ABT 3.3 TO 5.3 INCHES BEHIND THE AFT LIMIT.  UNDER THESE CONDS, THE ACFT'S MANEUVERING STABILITY & STICK FORCE PER 'G' CHARACTERISTICS WOULD HAVE BEEN SERIOUSLY DEGRADED.  IN TURN, THIS WOULD HAVE ALLOWED THE PLT TO EXCEED THE STRUCTURAL DESIGN LIMITS OF THE ACFT WITH LITTLE OR NO EFFORT.  AN EXAM OF THE WRECKAGE DISCLOSED EVIDENCE OF APPARENT FLAP ASYMMETRY, A COND WHICH WAY HAVE OCCURRED DRG THE IN-FLT BREAKUP OF THE ACFT.

## Sequence of events

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

- Loss of control - in flight, descent - normal
  - aircraft weight and balance - exceeded, pilot in command (cause)
  - weather condition - turbulence in clouds (contributing factor)
- Airframe/component/system failure/malfunction, descent - uncontrolled
  - flight control,flap - asymmetrical
  - design stress limits of aircraft - exceeded, pilot in command (cause)
  - wing - overload
- In flight collision with terrain/water, descent - uncontrolled

## Aircraft

- Registration: [N9435Q](https://openairdocs.org/deregistered/N9435Q-1993-06-10), registration cancelled 1993-06-10, S/N D9317 (OpenAirDocs)
- Reported make and model: BEECH V35B
- Registry model: [Beech V35B](https://openairdocs.org/model/beech-v35b) (registry code 1151548) (OpenAirDocs)
- Category: Airplane
- Serial number: D-9317
- Airframe hours: 3883
- Engines: CONTINENTAL IO-520-BA 285 horsepower reciprocating
- Damage: Destroyed
- Flight: Business, Part 91
- Operator: Bonanza 9435 Quebec
- Registered owner: Bonanza 9435 Quebec
- Airworthiness certificate: Standard, Utility
- Last inspection: Annual, April 26, 1991, 7 hours before
- Departed: ADS, ADDISON, TX
- Destination: AUS, AUSTIN, TX
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 315 total, 38 in this make and model, 241 as pilot in command, 5 in the last 90 days, 2 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 210° at 9 knots
- Visibility: 5 statute miles
- Lowest ceiling: 1,700 ft broken
- Temperature: 81 °F, dew point 73 °F
- Altimeter: 29.00 inHg

## 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 19910516016219A](https://openairdocs.org/incident/19910516016219A), May 16, 1991: Beech V35B, Austin, TX, Destroyed, 4 fatal. Broke up in flight in severe turbulence. Assymetrical flap extension. Flap drive shaft improperly secured. Aft CG

## Other investigations on N9435Q (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 FTW83LA073](https://openairdocs.org/ntsb/FTW83LA073), Jan 2, 1983: Beech V-35B (N9435Q), Big Spring, TX, substantial damage

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.

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