# NTSB NYC91LA249: Davis D1K, N158Y, Chester, CT, September 29, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 29, 1991, 09:30 local (13:30 UTC)
- Place: Chester, CT
- Location: 41.4032° N, 72.4509° W: Placed by OpenAirDocs: center of Chester, CT, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=41.4032&lon=-72.4509&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report May 5, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 37022
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC91LA249
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/37022/pdf
- Page: https://openairdocs.org/ntsb/NYC91LA249

## Probable cause

IMPROPER MAINTENANCE ON THE ENGINE WHICH RESULTED IN A POWER LOSS DUE TO A STUCK EXHAUST VALVE AND SUBSEQUENT FORCED LANDING IN UNSUITABLE TERRAIN.

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, takeoff - initial climb
  - engine assembly,valve,exhaust - open (cause)
  - procedures/directives - not followed, other maintenance personnel (cause)
  - procedures/directives - not followed, pilot in command
  - remedial action - not possible, pilot in command
- Forced landing, descent - emergency
- In flight collision with object, landing - flare/touchdown
  - object - tree(s) (contributing factor)

## Analysis

THE PILOT DEPARTED WITH A GLIDER IN TOW AND LOST POWER. HE CUT AWAY THE GLIDER WHICH LANDED WITH MINOR DAMAGE AND LANDED THE AIRPLANE IN A WOODED AREA.  EXAMINATION OF THE ENGINE REVEALED IT WAS BEING OPERATED WITH AUTO GAS WITHOUT AN STC.  A COMPRESSION CHECK THAT MEETS FAA SPECIFICATIONS HAD NOT BEEN CONDUCTED ON THE ENGINE SINCE 1963, AND CARBON LIKE COMBUSTION DEPOSITS HAD BUILT UP ON THE EXHAUST VALVE IN THE NUMBER 3 CYLINDER, KEEPING THE EXHAUST VALVE FROM CLOSING.  THE AIRPLANE AND ENGINE WERE 6 HOURS OUT OF AN ANNUAL INSPECTION.

## Aircraft

- Registration: [N158Y](https://openairdocs.org/aircraft/N158Y), registered now, S/N 508, built 1930 (OpenAirDocs)
- Reported make and model: Davis D1K
- Registry model: [Davis D-1-K](https://openairdocs.org/model/davis-d-1-k) (registry code 2740504) (OpenAirDocs)
- Registry engine: [Continental C125 series](https://openairdocs.org/engine/continental-c125-series) (registry code 17011, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 508
- Airframe hours: 2300
- Engines: CONTINENTAL C-125 125 horsepower reciprocating
- Damage: Substantial damage
- Flight: Part 91
- Operator: Richard S. Patenaude
- Registered owner: Richard S. Patenaude
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, August 26, 1991, 15 hours before
- Destination: 4B9, SIMSBURY, CT
- Airport: 3B9, Chester, runway 17, 2,566 × 50 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 61; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: rear; flight hours: 973 total, 219 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: variable at 3 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 55 °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 19910929048189A](https://openairdocs.org/incident/19910929048189A), Sep 29, 1991: Davis D1K, Chester, CT, Substantial damage. Engine quit on glider tow. Released glider. Stalled into trees. Stuck exhaust valve. Residue from auto gas in engine

## Other investigations on N158Y (2)

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 NYC94LA080](https://openairdocs.org/ntsb/NYC94LA080), May 15, 1994: Davis DK-1 (N158Y), East Haddam, CT, substantial damage. Probable cause: THE PILOT'S FAILURE TO MAINTAIN THE PROPER GLIDEPATH DURING LANDING APPROACH.
- [NTSB NYC73DNE28](https://openairdocs.org/ntsb/NYC73DNE28), Apr 14, 1973: Davis D-1K (N158Y), Chester, CT, 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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