Piaggio P180 N401WS

Summary

On 31 October 2012 at about 13:30 local time, a Piaggio P180 registered N401WS, operated by Flagship Private Air, LLC, was involved in an accident near Boyne City, Michigan, 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

31 October 2012 at 13:30

Classification

Accident

Location

Boyne City, Michigan, United States

Nearest airport

Boyne City Municipal Airport (N98)

Coordinates

45.2089, -84.9900

Aircraft

Piaggio P180

Registration

N401WS

Category

Airplane

Engines

2

Operator

Flagship Private Air, LLC

Operating rule

Part 91: General Aviation

Purpose of flight

Positioning

Phase of flight

Not recorded

Route

Detroit → Boyne City

Aircraft damage

Substantial

Weather

IMC

Light

Day

NTSB number

CEN13FA038

Nobody was injured.

The select/bypass valve's failure to seal correctly because of improper shimming, which resulted in an uncommanded and uncontrollable left turn during landing. Contributing to the accident was the overhaul facility's improper overhaul of the steering manifold.

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

Read the full NTSB narrative

The pilot stated that, during landing, the nosewheel steering was not engaged and that, after the airplane touched down, it made an uncommanded left turn. The pilot used landing gear braking and reverse thrust to control the airplane, but it still continued to veer left and then off the runway. The airplane struck the airport perimeter fence and a tree and came to rest. Postaccident examinations and tests of the nosewheel steering system and its associated components revealed that the steering actuator did move uncommanded at varying rates and directions when electrical power was off and hydraulics were engaged to the nosewheel steering system. Further, this occurred as a result of the select/bypass valve's failure to seal properly when in an unpowered state due to incorrect shimming within the select/bypass valve, which allowed hydraulic fluid to enter the servo valve when the system was off. The available hydraulic pressure was then ported to move the steering actuator relative to the position of the servo valve spool. Examinations also confirmed that, when the servo valve was electrically powered off, the spool could slightly free-float, and the unpowered spool position could be biased in the direction of the last commanded travel from when the system was last engaged. Examination of the rest of the airplane revealed no other mechanical malfunctions or failures that would have precluded normal operation. The nose landing gear assembly was overhauled 7 days before the accident. However, the postaccident examinations revealed that the overhaul was not conducted in accordance with the manufacturer's component maintenance manual and did not meet the requirements of Service Bulletin 80-0249, which was required by Airworthiness Directive (AD ) 2009-21-08 rev 1, even though the maintenance records indicated that the AD was completed and signed off by the operator for the accident airplane.

Quoted verbatim from the NTSB record.