Chris Leat

I have a some comments on this proposed rule. In the sections about "Actions since AD 86-07-01 was issued" It suggests that the latest revision of 72-7775 allows ECI instead of FPI. It actually allows ECI as an alternative to FPI. I didn't want readers to get the idea that FPI wasn't acceptable, as the SB actually says if the ECI inspection detects a crack then FPI should be used to determine the length, which then leads to the subsequent course of action. It also says that Red Dye is no longer considered an acceptable method of inspection. Red Dye is not mentioned in the current version of the service bulletin. I'm guessing that the original issue of 72-7775 said Red Dye was acceptable but an intermediate revision changed this to FPI ? In the AD proper, section 2(c) Applicability calls up a RB21-534E4-37 and repeats this 4 times. It is of course the RB211-535E4-37 and I guess the other affected marks should have been listed here. RB211-535E4-37, RB211-535E4-B-37 (and RB211-535E4-B-75) that don't incorporate RB211-72-8045. I have reviewed how COCs have been modified over the years. The conclusion is that all standards of COCs introduced after 72-8045 have the features (introduced by 72-8045) such that the inspection is not necessary. Therefore the wording for the applicability section might be changed slightly to say something along the lines of "......that don't incorporate RR Service bulletin (SB) RB.211-72-8045 or subsequent COC service bulletins, which limits the requirements of this inspection to COC part numbers UL18736 and UL18740 only. These engines...." I can also confirm that a basic mandatory feature of a RB211-535E4-C engine is to have a so called "Phase 5 combustor" to meet the emissions requirements applicable at the time of certification. This is introduced by SB 72-C230 which, as part of the package, instructs a new COC which has the relevant features (or better) of 72-8045. Consequently the RB211-535E4-C does not need to be covered by the re-issue of (or AD to supersede) 86-07-01 addressing SB 72-7775. Thanks