The A340 GTF test results await Airbus' release. Might today's article,
P&W rules out any early move to offer GTF architecture for widebody powerplant
suggest these results show no short term advantage for the A340? The GTF have a number of hurdles before use on large airframes (A340/350 etc) certification. It is an added mechanical section that requires substantial testing and flight time prior to use in, for example, ETOPS. P&W decision on lower thrust focus allow a more conservative learning curve.
The real problem is the weight of the gearbox, which makes the GTF non-competitive with Rolls-Royce Trents at high thrust ratings.
RR have always described the GTF as a "two-and-a-half shaft" engine, by implication inferior to their 3-shaft designs. But RR accepts that scale down a 3-shaft below 35,000 lbs thrust has not yet become viable.
The reason for testing a GTF on an A340 is not that it has the potential to power that aircraft commercially but because it can perform happily on only three engines, making it a very safe environment for testing.
The GTF is ideally suited to the C-Series and the MRJ, a part of the market where neither GE nor RR has a modern contender.