# NTSB WPR09CA152: Kenneth K Knowles Sonex, N997KK, Cottonwood, AZ, March 18, 2009

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Data collection · Final report
- Date: March 18, 2009, 10:30 local (17:30 UTC)
- Place: Cottonwood, AZ
- Coordinates: 34.747776, -112.048889 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=34.7478&lon=-112.0489&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Defining event: [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report June 11, 2009
- Report: Approved by Office Director
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 73508
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR09CA152
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73508/pdf
- Page: https://openairdocs.org/ntsb/WPR09CA152

## Probable cause

The loss of engine power for undetermined reasons.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md)
- [Object/animal/substance: tree(s)](https://openairdocs.org/ntsb-findings/03022020): Environmental issues › Physical environment · Contributed to outcome; cases with it: [All aircraft, 933 cases](https://openairdocs.org/ntsb-findings/03022020/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)

## Analysis

The pilot experienced a total loss of engine power during the first takeoff of the newly completed homebuilt experimental airplane. The pilot attempted to restart the engine but was unsuccessful. He then executed a forced landing in an open field. During the landing sequence the airplane sustained substantial damage to the left wing when it struck scrub chaparral. Post examination of the airplane and engine by an FAA inspector did not reveal any pre-impact malfunctions that would explain the loss of power.

## Factual narrative

The pilot experienced a total loss of engine power during the first takeoff of the newly completed homebuilt experimental airplane. The pilot attempted to restart the engine but was unsuccessful. He then executed a forced landing in an open field. During the landing sequence the airplane sustained substantial damage to the left wing when it struck scrub chaparral. Post examination of the airplane and engine by an FAA inspector did not reveal any pre-impact malfunctions that would explain the loss of power.

## Aircraft

- Registration: N997KK (not matched to a registry record)
- Reported make and model: Kenneth K Knowles Sonex
- Category: Airplane, amateur-built
- Serial number: 0531
- Engines: Aeroconversions Aerovee 80 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Special, Experimental light sport (Special)
- Last inspection: Condition, December 5, 2008
- Departed: P52, Cottonwood, AZ
- Destination: P52, Cottonwood, AZ
- Airport: P52, Cottonwood Airport

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 89; injuries: none; private; airplane ratings: single-engine land; medical: sport pilot; last flight review January 17, 2009; seat: left; flight hours: 1,883 total, 1 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 340° at 5 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 64 °F, dew point 27 °F
- Altimeter: 30.00 inHg
- Observed at: PRC, 20 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 20090318004099A](https://openairdocs.org/incident/20090318004099A), Mar 18, 2009: Amtr SONEX, Cottonwood, AZ, Substantial damage. (-23) Aircraft on climb phase of flight lost engine power and quit. Aircraft landed in open field and sustained extensive damage to the left wing leading edge.…

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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