Too much metal causes hard alpha cracks

It’s so nice to work with smart, savvy colleagues. Take the US Editor of Air Transport Intelligence, Lori Ranson , who joined us from the competition not so long ago, thank God, and who yesterday pointed out that the CF34-3B1 engine fan blade defect story comes on the heels of the DOT IG’s finding that lapses in monitoring suppliers by manufacturers and the FAA have caused faulty components to be installed on aircraft.

Let me be the first to say – and for the RECORD – it is not confirmed in any way, shape or form that there is any sort of correlation between the two. But it is a very interesting point.

On February 26, the DOT IG revealed its assessment of the FAA oversight of aircraft manufacturers’ quality assurance systems for domestic and foreign aircraft part suppliers.

“We found that FAA’s risk-based oversight system for suppliers needs improvement as it does not consider the degree to which manufacturers now use suppliers to make aviation products,” says the DOT IG.

“Specifically, (1) FAA has not ensured that manufacturers are providing oversight of their suppliers, (2) FAA does not require inspectors to perform enough audits of suppliers to determine how well manufacturers’ quality assurance systems are working, and (3) the systemic deficiencies we identified at 21 supplier facilities indicate that both manufacturers and FAA need to strengthen their oversight of these facilities.”

The timing is mad. GE today told me that a population of 13,000 fan blades from General Electric CF34-3B1 engines that power Bombardier CRJ200 aircraft have been identified by the engine manufacturer as being defective.

The admission comes after the US National Transportation Safety Board (NTSB) yesterday issued recommendations to the FAA citing a safety concern raised by two engine failures on CF34-powered CRJ200s.


In both instances – a 27 July 2006 engine failure on an Air Nostrum CRJ shortly after takeoff from Barcelona, Spain, and a 24 May 2007 engine failure on an Atlantic Southeast (ASA) airlines CRJ while in cruise flight from Syracuse to Atlanta – a fan blade on a CF34-3B1 turbofan engine fractured, causing a loud bang, severe vibration and in one case an engine fire.

These blades were produced between late 2002 and late 2006 by Teleflex Aerospace Manufacturing Group, and rough estimates show they are present on about 1,500 CF34-3B1 engines, says a GE spokesman.

Okay, it was a metallurgical issue. I could pretend that I completely understood that at 7am this morning, but I’d be lying through my bloomen teeth. By 8am, however, I was informed by GE that it meant that fan-blade supplier Teleflex Aerospace Manufacturing Group, a US-based company that sends machining to Mexico, received from “a certain shipper” a large billet of titanium alloy that contained a higher percent of aluminum than appropriate.

The result, says GE, is that hard particles “line up together” to form an aligned hard alpha and, over time, a crack can form.

Diversified industrial firm Teleflex in 2007 sold its Teleflex Aerospace Manufacturing Group unit to UK aerospace firm GKN.

Teleflex Aerospace president John Suddarth says it would be inappropriate to comment on a firm that is no longer part of the Teleflex company.

GKN has declined comment.

And Bombardier is keeping its comment brief. “Bombardier and GE will continue to work together to address the safety recommendations raised by the NTSB. We will not compromise the safety of our products,” says a spokesman.

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