Monday, October 2, 2017

Chrome Plating Failure Can Make Aircraft Accident

The Story of Aircraft Accident

Chrome plating is good metal surface protection, but it should be used in correct place and application. We can’t coat all metal using this method because its look like better performance. Nowadays people like to crome their motor bike engine and all of part of their bike in order look good performance. This is not wrong but can not be applied to all part like engine parts. This can be dangerous, you can see the story of aircraft accident because of their engine part apply of chrome plating.

taken from google book Willey
aircraft accident

The story are as follows; aircraft with four engine, propeller driven transport plane had just touched down when the left main wheel assembly separated. This plane slewed off runway and fire merge on the wing and engine of the left side. However the result of detail investigation, inter granular fracture was observed without evidence of fatigue striations. It was concluded that trunnion arm had failed because of corrosion and cracking.

Trunnion arm was made from a fine grained, through hardened and tempered 4340 steel. It had been subjected to excessive wear in repair, and during the overhaul it was known that already chrome plated to bring the dimensions can fulfill the specification. After use and worn trunnion arm back to the original level. Found that beneath the chrome plating and adjacent to the fracture, a regular pattern crack was found, but don’t continuous to the chrome plated, this indicate that this were not due to plating crack. The crack actually just 0.5 mm in depth, which caused by overheating occurred during grinding before hard crome applied. So chrome plating need perfect prepare before applied so some fist treatment like grinding is must be done before it being chrome.