As has been posted here by others, it is indeed the front spar Mod 2429 that is outstanding, however this is scheduled to take place during one of the forthcoming winter sevices.
As goes FI, she will be far lighter on the fatigue than some may think, even during her display years, she only consumed FI at a rate of 3 – 4 units per year. After recieving Mod 2429, she will have in the region of 70 FI units remaining, so as you can see, fatigue is not really a major issue with the aircraft.
Engines, however, are a different story, with their revised lifing schedule of 1200 cycles. A cycle is considered to be one excursion from Idle – Max – Idle. There are calculations for partial cycles, however, these are not something I know off the top of my head!! However, this illustrates the fact that it will be the engine life that dictates XH558’s future on the circuit, as once these cycles are gone, there is no option to re-life or rebuild the engines, so 558 will be grounded. To this end, the engines will be cycled through the airframe at 50 hr intervals, to ensure that usage and wear is spread evenly throughout the 8 spare engines that TVOC have.
Hope that answers a few questions.
Flipflopman
thanks FFM, i worked out that at the TVOC quoted 0.6-0.7 cycles per flight hour that even if each engine acheived 600 in-flight cycles 558 would still have 857.14 hours per engine until no cycles remain, @ 800 IFC’s it goes out to 1142.85 hours per engine, say that each engine will use 200 cycles for ground running/testing during 558’s display life then maximum possible flight hour life per engine is 1428.57 hours per engine, so should 1000 IFC’s be achevied on each engine 558 has a potential for 2,857.14 flight hours, which would far exceed her remaining FI.
indeed even if each engine only survives to 600 IFC’s they should still give 1,714.28 flight hours across the 8, still enough to exceed her remaining FI.
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