Beechcraft A36 N3670S

Summary

On 10 May 2004 at about 16:30 local time, a Beechcraft A36 registered N3670S was involved in an incident near Daytona Beach, Florida, United States. 2 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

10 May 2004 at 16:30

Classification

Incident

Location

Daytona Beach, Florida, United States

Coordinates

29.0781, -81.0444

Aircraft

Beechcraft A36

Registration

N3670S

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Flight Test

Phase of flight

Not recorded

Route

Daytona Beach → Unknown

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

MIA04IA088

Nobody was injured.

Improper maintenance/installation by the propeller overhaul/repair facility, which resulted in stress related fatigue and the eventual separation of the propeller pitch change pin.

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

Read the full NTSB narrative

The mechanic stated that he and the pilot were conducting a maintenance test flight, when the incident occurred. He further stated that after takeoff, and during climb to cruise, at an altitude of 1,000 feet AGL, as the pilot reduced power from 2,700 rpm to 2,500 rpm, all of a sudden there was a loud bang, and the airplane started to shudder and shake violently. He stated that the pilot reduced power, and returned for an otherwise uneventful landing. Examination of the airplane revealed that one blade of the three-bladed McCauley propeller appeared to be in negative pitch, and when moved, it revolved freely in the hub. Further examination revealed that the pitch change actuating pin for the No. 3 propeller blade had separated, with a threaded portion of the pin still remaining in the hub. On May 10, 2004, the incident McCauley propeller blade, and associated propeller parts, were examined at the NTSB Metallurgical Laboratory, Washington DC. The examination revealed that for the affected blade, the ferrule hole into which the fractured pitch change actuator pin had been inserted, had threads that did not extend into the hole as specified by the propeller manufacturer. The threads extended about one half the distance from the bottom of the hole, and fatigue cracking was found to be in the threads of the pin, and the fatigue crack had progressed about 95 percent of the way through the pin before it separated due to overstress. Records indicated that the propeller had last been overhauled on January 30, 1997,by a maintenance facility in Johnson City, New York, about 678 flight hours prior to the incident..

Quoted verbatim from the NTSB record.