Why would it need a D check? It's effectively a brand new airplane - less than 100 hours.
The calender limits for A checks I believe is 2 months, 18 months for C checks, and 72 months for D checks. Checks generally have 4 triggers, hours, cycles, calender time, and ADs. Corrosion/cracks are a function of cycles and calender time, fluids/grease often need replacing on calender time/cycles, tanks need cleaning based upon calender time etc.
Note that was written just as the PIP flight test was getting started - we didn't have any data.
GE had data. The PIP engine has parts that are fairly different to the original, and those changes were not done by guessing.
We 'beat' expectations and got a full 2% (as I noted, I didn't know if that was public knowledge until I saw it in the local newspaper).
The GEnx-2B missed the target TSFC by at least 2-3% at EIS. The fan on the GEnx-2B is simply too small, they are geometrically constrained to make it larger. The 747-8 engine is not as efficient as the 77W (fan size impact).
The PIP target was for an improvement of the TSFC of 1.6% (
Boeing conducts test flight of 747-8 with PIP), still not matching the original spec. Even if they managed to get 2% TSFC improvement, they are still not at the spec level.
Despite trying to make out this is super confidential information, the values are on the web if you know where to look, and how to read the data. One can easily go to
EASA - Individual Engine Datasheets and pull up individual engine test results. The test results show the GEnx-2B67 is around 5% behind the TSFC of the A380 powerplants, and around 10% behind the 787 powerplants.
As a bit of a comparison (30% thrust) of of TSFC (lb/lbt/hr)
524H-T 0.3432 (744)
Trent 700 0.3162 (333)
CF6-80C2B5F 0.2966 (744ERF)
Trent 877 0.2928 (772)
CFM56-5C 0.2904 (343)
Trent 892 0.2859 (733)
GEnx-2B67 0.2751 (748)
GE90-115B 0.2587 (77W)
Trent 972 0.2551 (A380)
GP7270 0.2517 (A380)
GEnx-1B64/P1 0.2440 (787)
Trent 1000-A2 0.2361 (787)
A 2% improvement to the TSFC (0.2967) still leaves the GEnx-2B67 a long way behind the A380 and 787, and also behind the 77W.
I'm certain Boeing has a better hack on the numbers now that the certification is almost complete.
Maybe the reason behind the announcement to reduce production rates further to 18 a year ???