Stinson 108 N343C

Summary

On 18 July 2016 at about 20:30 local time, a Stinson 108 registered N343C was involved in an accident near Haines, Alaska, United States. 4 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

18 July 2016 at 20:30

Classification

Accident

Location

Haines, Alaska, United States

Nearest airport

Haines (HNS)

Coordinates

59.2439, -135.5236

Aircraft

Stinson 108

Registration

N343C

Category

Airplane

Year built

1947

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Skagway → Haines

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ANC16LA048

Nobody was injured.

The pilot’s failure to maintain directional control of the airplane during the landing roll with a quartering tailwind, which resulted in a ground loop and overstress failure of the left main landing gear wheel axle. 

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The private pilot stated that, during the landing roll in the tailwheel-equipped airplane, he started a right turn to exit the runway using a high-speed taxiway when the airplane had slowed to about 20 mph. During the exit, the airplane made an abrupt right turn that the pilot could not control with left rudder and brake. The left wheel axle fractured, followed by a collapse of the left landing gear leg, which resulted in substantial damage to the airplane. The reported wind was a left quartering tailwind of 4 knots. The pilot and passenger observed variable gusting wind immediately after the accident. Postaccident examination after recovery of the wreckage found that the tailwheel attachment bracket was fractured. An examination of the left main landing gear axle weld fracture with a scanning electron microscope (SEM) revealed features consistent with tensile overstress that would have occurred during the accident sequence. An examination of the airframe tailwheel mount fracture surface with a SEM revealed signatures consistent with overstress failure, and other fracture areas of widespread corrosion. Photographs taken before the airplane was removed from the runway showed the tailwheel assembly in its normal position, with no abnormalities visible. Also, during the recovery of the airplane, no tailwheel separation or abnormal function was observed. Based on the examinations of the fractured components, there is no evidence that the fracture of the tailwheel mount led to a displacement of the tailwheel assembly or a loss of control during the landing. Based upon the pilot and passenger's statements regarding wind at the accident site, it is possible that an unexpected gust of quartering tailwind initiated a loss of control, and the high groundspeed and heavy landing weight contributed to increased lateral loads on the left landing gear during the ground loop, which resulted in overload failures of the axle and tail bracket welds.

Quoted verbatim from the NTSB record.