It's the same wing, more or less. It's a straight bolt-on, bolt off - more or less. And what's more, it's the CHEAPEST SHORT TERM SOLUTION - that may well be the clincher.
And the >FL290-300 problem is mainly due to traffic levels in Euronazi airspace. And since WE are in Euronazi airspace, it's a problem our J's must have going ANYWHERE (since they have to start here!). Besides, I thought the J was RVSM compliant?
I'm told (by a J pilot) that your fuel consumption in mid-20s is pretty much the same as ours, give or take. True? This REALLY should have been anticipated, and external tanks fitted - but then, that would require somebody in the procurement chain to admit a flaw in the plan....
Sadly, the J has suffered badly from lack of forethought right through the procurement and into-service phases - it may be (slightly) faster (when allowed) and have more power, and more toys, but it is nowhere near what it really ought to be - which is a shame.
16B