Cessna 170A N1742D

Summary

On 28 May 2011 at about 00:20 local time, a Cessna 170A registered N1742D, operated by Bradley R Subers, was involved in an accident near Wasilla, Alaska, United States. 2 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

28 May 2011 at 00:20

Classification

Accident

Location

Wasilla, Alaska, United States

Nearest airport

Wasilla (IYS)

Coordinates

61.5389, -149.5394

Aircraft

Cessna 170A

Registration

N1742D

Category

Airplane

Engines

1

Operator

Bradley R Subers

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Palmer → Wasilla

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ANC11LA039

Nobody was injured.

The pilot's loss of directional control during landing, which resulted in a runway excursion. Contributing to the accident were the effects of multiple modifications to the main and tailwheel landing gear through the supplemental type certificate and FAA field approval process, which adversely changed their geometry, and resulted in degraded controllability during landing.

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

Read the full NTSB narrative

The pilot said that, when the tailwheel-equipped airplane touched down during a three-point landing, it immediately veered sharply to the left and exited the runway. She was unable to regain control before the airplane collided with a ditch. The airplane had recently been purchased, and the pilot did not have any flight time in the make and model prior to the purchase. The airplane had been modified with larger/taller main landing gears, larger diameter tires, and a tailwheel assembly from another model of airplane. The pilot said that when the previous owner demonstrated the airplane, he used heavy braking and excessive thrust to get the tailwheel to straighten out. He told her he always did wheel landings as opposed to three-point full stall landings. A postaccident examination of the airplane revealed that the rotational plane of the tailwheel was not horizontal/parallel to the ground. There was a pronounced negative camber (aft downward tilt), which caused the tailwheel to rotate forward when weight was applied. The tailwheel spring had been extended aft from its normal position, which added additional negative camber. An engineer from the Federal Aviation Administration aircraft certification office said adjustments to the tailwheel should have been made to make the tailwheel's plane of rotation horizontal. An examination of the airplane's airframe logbook revealed that the airplane's landing gear had been modified under a supplemental type certificate and multiple field approvals. The airplane had been inspected for maintenance conformity, but not engineering. Due to the multiple landing gear modifications, it is likely that the airplane's landing characteristics were degraded, requiring greater pilot vigilance and skill, particularly during landing.

Quoted verbatim from the NTSB record.