Delays to the Rolls-Royce Trent 7000 programme lie behind the initial restriction of extended twin-engine operations (ETOPS) for the Airbus A330-900.
While approval for 330min ETOPS is being sought for the Trent 7000-powered twinjet, the European Aviation Safety Agency states that the manufacturer has yet to complete particular inspections.
The A330-900 has been cleared for 180min ETOPS but with an engine-use limitation of 500 cycles.
EASA outlines several criteria for “early ETOPS” certification, which permits ETOPS clearance at entry into service of a new aircraft and engine combination.
It requires an approval plan to be submitted to EASA, including a validation test simulating ETOPS service comprising 3,000 full start-stop cycles, from take-off through to landing and reverse thrust, plus three simulated diversions for the ETOPS level sought.
At the end of this test the engine must be visually inspected and then completely disassembled, with the propulsion system hardware examined for airworthiness and any potential sources of in-flight shutdown or loss of thrust control.
Rolls-Royce has “not yet completed” the full engine strip-down and inspection following the 3,000-cycle test, says EASA.
It states that the programme delays have not allowed sufficient time to perform the complete disassembly prior to entry into service.
“The failure to show full compliance from a detailed strip examination at 3,000 cycles life is seen as a reduction in the confidence, which is normally required for full ETOPS approval,” says EASA.
It is granting 180min ETOPS along with the engine-cycle restriction as a mitigation measure.
“This is a conservative approach, restricting usage well within the demonstrated levels, and thereby giving confidence in engine reliability,” says EASA.
But it adds that Rolls-Royce needs to demonstrate full compliance before the end of December, else ETOPS approval will be “withdrawn”.
TAP Portugal took delivery of the first A330-900, the larger of the two A330neo-family variants, during a ceremony in Toulouse on 26 November. The aircraft, MSN1836, is a sister ship to another TAP A330neo, MSN1819, used to conduct route-proving trials earlier this year.
Rolls-Royce says it is aiming to meet the EASA requirements on ETOPS before the year-end deadline.