If I may pile onto VFD's skepticism ...
Qantas pays for power by the hour, as far as cycles are concerned then the loss of revenue would be for the time for a 4 engine change, the turbine cost would have been on RR.
75 cycles, that is looking at turning the clock back to recip reliabilaty days.
I find it hard to believe that Qantas or anyone else would have bought into that.
Something in the last two pages doesn't make sense to me. I suspect that the info is incomplete.
75 cycles (launch to land) to mandatory replacement (take off wing) four engines from an A 380. If I may spell out why it puzzle me. Please explain where in my understanding there are gaps, holes, or poor assumptions.
A 380 is a long haul aircraft. I have a very modest understanding of long haul optimization decisions, which inform a company which airframe to buy and fly for the expected/forecast route structure.
I'll estimate the bounds of profitable legs/sectors to be between 5-12 hours long. (If this is way off, please advise). That would put a given A380 in need of new engines (four) in somewhere between 375 hours and 900 hours. At something like $12 million per copy, for ease of illustration, it looks like they cost more than that, that's $48,000,000 expense on engines alone in 75 sectors ...
Makes no fiscal sense to me.
For X amount of servicing, versus replacement, it would make more sense. That said, you still eat X' amount of time (which is money and days of no revenue) getting four new engines on and checked out before you release the airframe to the line for operations - the next 75 anyway. Is this a cycle that most airline companies would accept, in terms of standard/mean time on wing for an engine? I suspect not, but would be pleased to be educated if I am wrong in my guess.
RR has been building reilable and durable engines for airliners for some decades.
Qantas wishes to operate at a profit.
A few back of the napkin cost curves leave me skeptical of the 75 cycles at face value.
Some information is missing, surely, or some context. (Is it 75 cycles for a major inspection cycle? )
Reference point:
Twenty five years ago, I operated GE T58-8F turboshaft engines that had a "high time" replacement interval of 600 hours (+/- 10%) on sorties that averaged from 2.5-6.0 hours. You'd get from 100 - 240 sorties if two matched engines worked as advertised out of the can. Many did. Most came "off wing" within the first 60-100 hours if they weren't going to make the interval.
The state of the art of engine design and manufacture has advanced a couple of generations since those T-58's were put together. The engines I used later were "modular" in design, so that overhauls were both simpler and some sections not needing them in as many hours as others ... I don't understand the Trent well enough to grasp if it has that same sort of modularity designed into it, but think it does.
I have difficulty believing that
a purpose built turbofan engine intended for a particular operating environment would have such a short replacement ( or overhaul) interval. Remove and replace, on a power by hour basis, leaves an awful lot of engines in rework/refit for the engine provider (RR) when you start looking at multiple airlines and dozens or hundreds of aircraft, each with four engines on wing ... my brain comes up with the term "churn" when I consider this prospect.
What information is missing from that 75 cycles data point?