# NTSB DEN90FA033: Beech B35-A33, N477T, Castle Rock, CO, December 16, 1989

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: December 16, 1989, 13:44 local (20:44 UTC)
- Place: Castle Rock, CO
- Coordinates: 39.370048, -104.850318 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.3700&lon=-104.8503&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report June 25, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 17813
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN90FA033
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17813/pdf
- Page: https://openairdocs.org/ntsb/DEN90FA033

## Probable cause

THE PILOT'S LOSS OF CONTROL AS A RESULT OF SPATIAL DISORIENTATION. FACTORS RELATED TO THE ACCIDENT WERE: THE ADVERSE WEATHER CONDITIONS.

## Sequence of events

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

- Loss of control - in flight, approach - iaf to faf/outer marker (ifr)
  - weather condition - obscuration (contributing factor)
  - preflight briefing service - not attained, pilot in command
  - spatial disorientation, pilot in command (cause)
  - weather condition - snow (contributing factor)
  - ifr procedure - improper, pilot in command (cause)
  - lack of recent instrument time, pilot in command (contributing factor)
  - weather condition - fog (contributing factor)
  - weather condition - low ceiling (contributing factor)
  - proper altitude - not maintained, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

A VFR FLIGHT PLAN HAD BEEN FILED BUT, WHILE ENROUTE TO DENVER IT WAS CHANGED TO AN IFR FLIGHT PLAN WHEN THE PILOT REALIZED THE WEATHER HAD DETERIORATED TO INSTRUMENT METEOROLOGICAL CONDITIONS. THE PILOT ACKNOWLEDGED A CLEARANCE FOR AN ILS APPROACH INTO CENTENNIAL AIRPORT, ENGLEWOOD, COLORADO, BUT DURING THE APPROACH HE SAID THAT HE WAS '...ALL TURNED AROUND AND WAS HAVING TROUBLE CONTROLLING THE AIRCRAFT.' THERE WAS NO FURTHER CONTACT WITH THE PILOT AND THE AIRCRAFT FAILED TO ARRIVE AT THE AIRPORT. A SEARCH WAS CONDUCTED AND THE AIRCRAFT WRECKAGE WAS FOUND SHORTLY AFTER DAYBREAK THE FOLLOWING MORNING. RADAR INFORMATION CONFIRMED THAT THE PILOT WAS FLYING IN CIRCLES AND HAD NOT ESTABLISHED HIMSELF ON THE APPROACH.

## Aircraft

- Registration: [N477T](https://openairdocs.org/deregistered/N477T-1998-07-07), registration cancelled 1998-07-07, S/N CD305 (OpenAirDocs)
- Reported make and model: BEECH B35-A33
- Registry model: [Beech 35-A33](https://openairdocs.org/model/beech-35-a33) (registry code 1151404) (OpenAirDocs)
- Category: Airplane
- Serial number: CD-305
- Airframe hours: 1921
- Engines: CONTINENTAL IO-470-K3 225 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Registered owner: Leroy Evans Bates, Jr.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, November 3, 1989, 8 hours before
- Departed: DHT, DALHART, TX
- Destination: APA, ENGLEWOOD, CO
- Flight plan: VFR/IFR
- Airport: APA, Centennial, runway 35R, 10,001 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 58; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 1,554 total, 63 in this make and model, 1,353 as pilot in command, 12 in the last 90 days, 1 in the last 30 days

## Weather

- Conditions: Instrument (IMC), Day
- Wind: 360° at 8 knots
- Visibility: 1 statute miles
- Lowest ceiling: 300 ft
- Temperature: 18 °F, dew point 16 °F
- Altimeter: 29.00 inHg
- Observed at: APA, 8 nm away

## 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 19891216051339A](https://openairdocs.org/incident/19891216051339A), Dec 16, 1989: Beech 35A33, Denver, CO, Destroyed, 2 fatal. Lost orientation on ILS approach and descended into a valley upslope. Lacked recent IFR experience. No biennial.

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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