Mitsubishi MU-2B-35 N770MA

Summary

On 24 August 2000 at about 07:15 local time, a Mitsubishi MU-2B-35 registered N770MA was involved in an accident near Corsicana, Texas, 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

24 August 2000 at 07:15

Classification

Accident

Location

Corsicana, Texas, United States

Nearest airport

C. David Campbell Field (CRS)

Coordinates

32.0792, -96.4605

Aircraft

Mitsubishi MU-2B-35

Registration

N770MA

Category

Airplane

Engines

2

Operator

Not recorded

Operating rule

Part 135: Air Taxi & Commuter

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Dallas → Houston

Aircraft damage

Substantial

Weather

VMC

Light

Night/Dark

NTSB number

FTW00LA242

Nobody was injured.

the in-flight separation of the propeller blade, which resulted from intergranular corrosion and fatigue cracking.

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

Read the full NTSB narrative

The twin-engine airplane was in cruise flight at 11,000 feet msl, when the pilot heard a loud bang and felt the airplane vibrate. The pilot shut down the right engine, feathered the propeller, and landed the airplane at an alternate airport. Examination of the right propeller revealed that one of its propeller blades separated approximately 8.5 inches from the hub. This blade was manufactured from 7076 aluminum alloy, which is referred to as a 'hard alloy.' Examination of the propeller blade's fracture surface revealed that it failed as a result of fatigue cracking, which originated from an area of intergranular corrosion. The propeller was overhauled 222 hours prior to the accident. According to the overhaul facility, they used a process of Alodining the blades for corrosion control, which is an approved method. According to the propeller manufacturer, the preferred method of corrosion control is anodizing due to its corrosion detection properties; however, it is a more expensive and time consuming corrosion control process. As a result of this accident, the propeller manufacturer issued a service bulletin indicating that 'hard alloy' blades should be removed from service due to their susceptibility to intergranular corrosion.

Quoted verbatim from the NTSB record.