Riskien Maailma

update: A380:n moottorivian syy selvillä

(MTV3-STT, 12.11.2010) Airbus-lentokoneita valmistava Rolls Royce ilmoittaa löytäneensä syyn Qantas-lehtoyhtiön superjumbon viimeviikkoiselle pakkolaskulle.

Yhtiö ei kertonut tarkasti, minkälainen löydetty vika oli. Se tyytyi toteamaan, että "tietty osa" moottorin turbiinitilassa petti, ja osan pettäminen aiheutti öljypalon. Yhtiö lupasi korvata viallisen osan toimivalla.

Rolls Roycen mukaan vika koskee ainoastaan Trent 900 -mallisia moottoreita.

UPDATE (AP 2010-12-2):

The ATSB, which is leading the international investigation into the Qantas breakup, added some specifics on Thursday, saying a section of an oil tube that connects the high-pressure and intermediate-pressure bearing structures of the engine was the danger area.

"The problem relates to the potential for misaligned oil pipe counter-boring, which could lead to fatigue cracking, oil leakage and potential engine failure from an oil fire," the ATSB said in a brief statement.

It called the problem "a potential manufacturing defect."

Counterboring involves placing a larger hole over a smaller hole to make room for a seal. The ATSB said a misalignment of those holes had produced a thinning of the oil pipe wall and fatigue cracks. That could have led to oil leaking into a section of the engine containing extremely hot gas — a mixture of burned fuel and air. If oil comes into contact with the hot gas, it will burn.

"It is a design error and obviously a major one," said Peter Marosszeky, a jetliner maintenance expert at the University of New South Wales.