If engine makers face the risk that plane types with new engines are withdrawn from service for occasional contained engine failures, there won't be any more new engine technology. One can't avoid real live testing as there may always be wrong assumptions in the testing procedure.
Slipper slope there, RR has "grounded" 787's the world over costing airlines and itself millions because of doing real life testing for sulfur in the atmosphere and its effects on its engines? I put grounded in quotes since the PC crowd may ask for a source that the a/c and or engine were actually grounded, honestly do not think I need to say parked and not flying while awaiting engine repairs as I assume on this aviation site everyone is aware of the issue.
I can't understand how engines are "developed". Engine maker and plane maker agree to design a new plane and a new engine in so and so many years.
If the engine maker already knows how to achieve the promised compression ratio, why does it take so many years? And if the engine makers don't know yet, how can they promise?
B747, Tristar, A340 were all victims of false promises, even though the B747 finally found a proper engine. The GE90 for B777-300ER turned out better than planned. So it seems these "plans" are really "hopes". How does one plan research results anyway?
On the other side it seems not feasible to first design the engine and then wait a few years for a plane for it. If the engine is mostly functional, one starts manufacturing and hopes to find a solution for the weak spots soon. Or the engine maker says "sorry", like with Lockheed Tristar or A340.
The German industry promised the German railway to build trains that can lean in curves, so that trains can drive faster on old tracks. They finally gave it up. Even though there were a lot of trains delivered. It seems they hoped to fix the weak spots "soon".
"Cracking problems in the intermediate pressure (IPT) section of the turbine have plagued the engine since early 2016, five years after its launch. ... According to Horwood, the problem was caused by sulphurisation; a chemical process affecting the nickel alloy which comprises the IPT blades. ...
The geometry around the root of the IPT blade concentrated air sucked in by the engine’s compressor system, which in some parts of the world (notably Asia) contained higher levels of sulphur-containing pollutants than the engine had been tested with. The temperatures within the IPT and some of the specialised coatings on the blade may have exacerbated the problem, Horwood said, producing air turbulence and local temperature increases that led to fatigue-like behaviour in the metal which resulted in cracking."https://www.theengineer.co.uk/rolls-roy ... rent-1000/
"The first run of the Trent 1000 was on 14 February 2006. First flight on Rolls-Royce's own flying testbed (a modified Boeing 747-200) was successfully performed on 18 June 2007 from TSTC Waco Airport. The engine received joint certification from the FAA and EASA on 7 August 2007 (7-8-7 in Europe).
The Trent 1000 is the launch engine on both initial 787 variants, the -8 with ANA and the -9 with Air New Zealand."https://en.wikipedia.org/wiki/Rolls-Royce_Trent_1000
That RR did "real life testing for sulfur in the atmosphere" is possibly what I meant. In their assumptions this problem didn't appear. And the problem appeared five years after entry into service and nine years after first flight on the B747 testbed. I can't find fault with RR for this problem. Which is not to say that they are not responsible for the financial damage and for maintenance.