GE Aviation reviewed the NPRM to 14 CFR Part 39 in Docket No. FAA

- 2011

- 0982;

Directorate Identifier 2011

- NE

- 09

- AD and has the following input and recommendations for changes to the proposal:

The NPRM is applicable to all CF6

- 80C2 engines. No new productio n engines are affected by the No. 3 B earing P acking nonconformance or misassembled. Also e ngines already complied with SB 72

- 1405 shop inspection

, have accomplished the requirements of proposed AD. GE recommends the applicability be changed to only those e ngines that have had a shop visit where the fan was removed from the core and CF6

- 80C2 SB 72

- 1405 was not complied at that time.

The NPRM requires the one time inspection to be done not later than 5500 CIS since last engine shop visit where the fan was r emoved from the core. The GE service bulletin 72

- 1405 contain s 5500 cycles as an economic threshold and not a hard life removal threshold. If parts continue in service beyond the 5500 cycles (with an incorrect packing) then the noted LLP parts need to be scrapped “at next shop visit”. GE has not determined that removal from service “prior” to 5500 cycles is required. GE recommends that the proposed AD be changed to allow continued operation beyond 5500 cycles. GE recommends one time inspection be perform ed at the next shop visit where the fan is separated from the high pressure compressor (HPC)

.
If the proposed AD requires the inspection to be completed not later than 5500 CIS since last engine shop visit where the fan was removed from the core, GE recom mends that instructions be provided in the proposed AD for the actions necessary for those engines in operation that have already exceeded 5500 CIS. GE has been made aware of currently 80 engines that have already exceeded 5500 CIS.

GE has developed bores cope procedure that can determine the configuration of the No. 3 Bearing P acking via borescope , with either with the engine installed on

- wing or with the engine removed and in the shop). The borescope procedure is effective in most engine configurations a nd can accurately determine packing configuration, without requirement to split the fan and core. The BSI procedure will be released via service bulletin 72

- 1427

. GE recommends the proposed AD allow use of this BSI procedure to determine configuration of the No. 3 Bearing Packing.

The following are specific changes that GE recommends to reflect the items above:

1. On page 64292, Discussion section, first sentence, change listed P/N From: “1292M70P04”, To: “1471M25P04”

2

. On page 64293, 2.(f)(1) recom mend changing from: “Perform a one

- time inspection ...” to: “For engines that have had a shop visit where the fan was separated from the high pressure compressor (HPC) and CF6

- 80C2 SB 72

- 1405 was not complied at that time, perform a one

- time inspection...” because no new production engines are affected by the
No. 3 B earing P acking nonconformance and engines already complied to the SB 72

- 1405 shop inspection have accomplished the requirements of the proposed rule.3 . On page 64293, section (f) (2) (ii), cha nge From: “......5,500 CIS or more with a packing

determined to be other than a “CORRECT FLOW” packing.......”, To: “......5,500 CIS or more with a packing determined to be “LOW FLOW” packing.......”,

4

. On page 64293, 2.(f) Suggest adding 2.(g)(4) “Introduction of an e ngine into a shop solely for core vibration trim balance procedure that requires separation of a major engine flange.” because this is similar to the maintenance actions listed in paragraph 2. (g ) (1), (2), and (3) of the NPRM

.