Clayton - Clayton

The airplane had not been flown for about 5 months and the purpose of the accident flight was a maintenance test flight after both engines had been replaced with higher horsepower models. Witnesses observed the airplane depart and complete two uneventful touch-and-go landings. The airplane was then observed to be struggling to gain altitude and airspeed while maneuvering in the traffic pattern. One witness, who was an aircraft mechanic, reported that he observed the airplane yawing to the left and heard noises associated with propeller pitch changes, which he believed were consistent with the "Beta" range. The airplane stalled and impacted trees in a wooded marsh area, about 1 mile from the airport. It came to rest about 80-degrees vertically. Examination of the wreckage did not reveal any preimpact malfunctions; however, the lack of flight recorders and the condition of the wreckage precluded the gathering of additional relevant information. Damage observed to both engines and both propellers revealed they were likely operating at symmetrical power settings and blade angles at the time of the impact, with any differences in scoring signatures likely the result of impact damage. The reason for the yawing and the noise associated with propeller pitch changes that were reported prior to the stall could not be determined.

Flight / Schedule

Clayton - Clayton

Registration

N157KM

MSN

57

Year of Manufacture

1967

Date

March 8, 2011 at 11:40 AM

Type

CRASH

Flight Type

Test

Flight Phase

Landing (descent or approach)

Crash Site

Airport (less than 10 km from airport)

Crash Location

Clayton Georgia

Region

North America • United States of America

Coordinates

33.5205°, -84.3592°

Crash Cause

Human factor

Narrative Report

On March 8, 2011 at 11:40 AM, Clayton - Clayton experienced a crash involving De Havilland DHC-6 Twin Otter, operated by Desert Sand Aircraft Leasing, with the event recorded near Clayton Georgia.

The flight was categorized as test and the reported phase was landing (descent or approach) at a airport (less than 10 km from airport) crash site.

2 people were known to be on board, 2 fatalities were recorded, 0 survivors were identified or estimated. This corresponds to an estimated fatality rate of 100.0%.

Crew on board: 2, crew fatalities: 2, passengers on board: 0, passenger fatalities: 0, other fatalities: 0.

The listed crash cause is human factor. The airplane had not been flown for about 5 months and the purpose of the accident flight was a maintenance test flight after both engines had been replaced with higher horsepower models. Witnesses observed the airplane depart and complete two uneventful touch-and-go landings. The airplane was then observed to be struggling to gain altitude and airspeed while maneuvering in the traffic pattern. One witness, who was an aircraft mechanic, reported that he observed the airplane yawing to the left and heard noises associated with propeller pitch changes, which he believed were consistent with the "Beta" range. The airplane stalled and impacted trees in a wooded marsh area, about 1 mile from the airport. It came to rest about 80-degrees vertically. Examination of the wreckage did not reveal any preimpact malfunctions; however, the lack of flight recorders and the condition of the wreckage precluded the gathering of additional relevant information. Damage observed to both engines and both propellers revealed they were likely operating at symmetrical power settings and blade angles at the time of the impact, with any differences in scoring signatures likely the result of impact damage. The reason for the yawing and the noise associated with propeller pitch changes that were reported prior to the stall could not be determined.

Aircraft reference details include registration N157KM, MSN 57, year of manufacture 1967.

Geospatial coordinates for this crash are approximately 33.5205°, -84.3592°.

Fatalities

Total

2

Crew

2

Passengers

0

Other

0

Crash Summary

The airplane had not been flown for about 5 months and the purpose of the accident flight was a maintenance test flight after both engines had been replaced with higher horsepower models. Witnesses observed the airplane depart and complete two uneventful touch-and-go landings. The airplane was then observed to be struggling to gain altitude and airspeed while maneuvering in the traffic pattern. One witness, who was an aircraft mechanic, reported that he observed the airplane yawing to the left and heard noises associated with propeller pitch changes, which he believed were consistent with the "Beta" range. The airplane stalled and impacted trees in a wooded marsh area, about 1 mile from the airport. It came to rest about 80-degrees vertically. Examination of the wreckage did not reveal any preimpact malfunctions; however, the lack of flight recorders and the condition of the wreckage precluded the gathering of additional relevant information. Damage observed to both engines and both propellers revealed they were likely operating at symmetrical power settings and blade angles at the time of the impact, with any differences in scoring signatures likely the result of impact damage. The reason for the yawing and the noise associated with propeller pitch changes that were reported prior to the stall could not be determined.

Cause: Human factor

Occupants & Outcome

Crew On Board

2

Passengers On Board

0

Estimated Survivors

0

Fatality Rate

100.0%

Known people on board: 2

Operational Details

Schedule / Flight

Clayton - Clayton

Flight Type

Test

Flight Phase

Landing (descent or approach)

Crash Site

Airport (less than 10 km from airport)

Region / Country

North America • United States of America

Aircraft Details

Registration

N157KM

MSN

57

Year of Manufacture

1967