Rolls-Royce had early warning of Trent 900 manufacturing problems

Trent 900 side view.JPGWe finally have part of an answer to a big outstanding question from last November’s uncontained Rolls-Royce Trent 900 engine failure on Qantas A380 flight QF32: what Rolls-Royce knew of the powerplant’s weakness and why the C mod was introduced.

Following QF32 it became clear problems on the Trent 900 were confined to two of three versions of the powerplant: the A mod and B mod. The latest version, C mod, was not affected. But don’t hang Rolls yet. The manufacturer said last year that although the problem did not exist on the C mod, Rolls was not aware of the problem and thus did not intentionally fix it. As the manufacturer’s head of corporate affairs told us:

“It is not true that we knew about a problem in the A and B versions of the engine and went on to correct it in the C version. There has been no design change relevant to this failure between A, B and C versions of the engine.”

So then why did Rolls-Royce introduce the C mod?

The problem, the ABC’s Four Corners reports (preview here), is that Qantas in April 2009 found a fractured oil vent pipe caused by a sub-surface void created in the welding process in Module 51, the same section that had a faulty stub pipe that produced a leak, caused a fire, and the uncontained failure on QF32.

In April 2009 Rolls-Royce also introduced the C mod, court documents show. The manufacturer began to upgrade early versions of the engine as aircraft came in for maintenance. But on 4 November VH-OQA, operating QF32, had not had its engines changed. The no. 2 engine, which experienced the failure, was an A mod. (Qantas has since replaced 23 engines and only operates B mod and C mod versions, chief executive Alan Joyce says.)

ABC reports sources familiar with the investigation say, quite reasonably, the April 2009 crack “should have made [Rolls-Royce] extra vigilant about the manufacturing standards of the pipes in that part of the engine, the bearing support assembly.”

Stub pipe QF32.jpgThose standards slipped, the ABC says. The stub pipe on A mod and B mod versions was drilled out during assembly in order to install an extra oil filter. The drilling, however, was not straight and caused one side of the pipe to be thinner than the other (right).

QF32 pilot Richard de Crespigny gives the ABC a frank assessment of Rolls: “Rolls-Royce know how to design engines. That may be a personal error that got through. I think there was human error in the construction.”

What does Rolls-Royce have to say? Unsurprisingly, nothing. An ABC spokeswoman explains:

Four Corners approached Rolls Royce for an interview when they began making the program and requested access to the Rolls Royce facilities in Derby and Singapore. Those requests were declined. Four Corners repeated the interview request on numerous occasions during the making of the program. In addition once there had been some criticism of Rolls Royce in interviews, Four Corners went back to Rolls Royce again offering them the chance to respond. They declined on each occasion.  Just before filming was completed Four Corners made a final request for an interview with Rolls Royce; it was also declined.

The Four Corners programme benefits from being a neutral party in the public’s eye, unlike anytime Qantas makes a statement and thus Qantas had every incentive to cooperate on a documentary to be shown nation-wide as the carrier looks to re-build its brand from QF32, but also looks to defend its brand from the encroaching Virgin Blue.

Qantas made its staff available to be interviewed as well as for ABC to film on the carrier’s premises, including an A380, but Qantas “had no access to the material before broadcast”, the ABC spokeswoman says.

The programme may be pro-Qantas and anti-Rolls, but that is how the currently known facts are.

With the new insight, return to my December question and see–I don’t know myself–if there is an answer yet to if Rolls-Royce neglected what its chief executive of Australasia, preached: “No aircraft will fly unless it is safe to do so.”

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