AD/CF34/5 Amdt 2

Fan Disks

6/2007

Applicability:

General Electric CF 34-1A, -3A, -3A1, -3A2, -3B and -3B1 series engines fitted with a fan disk, part number (P/N) 5921T18G01, 5921T18G09, 5921T18G10, 5921T54G01, 5922T01G02, 5922T01G04, 5922T01G05, 6020T62G04, 6020T62G05, 6078T00G01, 6078T57G01, 6078T57G02, 6078T57G03, 6078T57G04, 6078T57G05 or 6078T57G06.

Note 1:  These engines are installed on but not limited to Bombardier Canadair aeroplane models CL-600-2A12, -2B16, and -2B19.

Requirement:

1. Remove from service fan disks listed by part number and serial number (S/N) in Table 1 of this AD.

Table 1 - Fan Disks that Require Removal

2. For CF34-3A1 and CF34-3B1 turbofan engines installed on Bombardier Canadair CL600-2B19 Regional Jet aeroplanes:

a. On-wing Tactile and Enhanced Visual (TEV) inspect the fan disks listed by P/N and S/N in Table 1 of GE Alert Service Bulletin (ASB) No. CF34-AL S/B 72-A0231, dated 7 March 2007 in accordance with paragraphs 3.A. through 3.A.(13) of the Accomplishment Instructions of GE ASB No.
CF34-AL S/B 72-A0231.

b. Fluorescent penetrant inspect (FPI), TEV inspect, and eddy current inspect (ECI) at shop-level for cracks and electrical arc-out defects on the fan disks listed by P/N and S/N in Table 1 of GE ASB No. CF34-AL S/B 72-A0233, Revision 2, dated 22 March 2007 in accordance with paragraphs 3.A.(1) through 3.A.(6) of the Accomplishment Instructions of GE ASB No.
CF34-AL S/B 72-A0233.

Shop Level Exemption.

Fan disks are exempt from the shop-level inspections that meet the following criteria:

(1) Fan disks inspected before the effective date of this AD per GE Engine Manual No. SEI-756, Section 72-21-00 (FAN ROTOR ASSEMBLY INSPECTION); and

(2) That have accumulated no more than 100 cycles since that inspection; and

(3) That pass the on-wing TEV inspection in Requirement 2a of this AD.

3. For CF34-1A, -3A, -3A1, -3A2, and -3B turbofan engines installed on Bombardier Canadair Models CL-600-2A12 (CL-601), CL-600-2B16
(CL-601-3A), (CL-601-3R), and (CL-604) Business Jet aeroplanes:

FPI, TEV inspect, and ECI for cracks and electrical arc-out defects at shop-level on the fan disks listed by P/N and S/N in Table 1 of GE ASB No. CF34-BJ S/B 72-A0212, Revision 2, dated 22 March  2007 in accordance with paragraphs 3.A. through 3.A.(10) of the Accomplishment Instructions of GE ASB No. CF34-BJ S/B 72-A0212, Revision 2.

Previous Credit

Credit is allowed for fan disks previously shop-level inspected using GE ASB No. CF34-AL S/B 72-A0233, original issue, or Revision 1 of that ASB dated
16 March 2007, or GE ASB No. CF34-BJ S/B 72-A0212, dated 7 March 2007 or Revision 1 of that ASB dated 16 March 2007, before the effective date of this AD.

Note 2:  FAA AD 2007-07-07 Amdt 39-15012 dated 30 March 2007 refers.  This AD supersedes FAA AD 2006-05-04.

Compliance:

1. For disks with fewer than 8000 cycles since new (CSN) as of the effective date of this AD, replace prior to accumulating 8000 CSN.

For disks with 8000 CSN or greater as of the effective date of this AD, replace within 15 days after the effective date of this AD.

2. a. In accordance with Table 2 of this AD.

Table 2. - Regional Jet On-Wing Fan Disk Inspection Compliance Times

2. b. Within 5,000 flight hours or 5 calendar years after the effective date of this AD, whichever occurs first.

3. In accordance with Table 3 of this AD.

Table 3. - Business Jet Shop-Level Fan Disk Inspection Compliance Times

This Amendment becomes effective on 7 June 2007.

Background:

This AD was prompted by advice that electrical arc-out, most probably caused during an electro-chemical etch process, may be present in certain fan disks fitted to GE CF34 series engines.  This condition can result in cracking of the fan disk that can ultimately lead to disk rupture and uncontained engine failure.

Amendment 1 corrected an error in the first disk listed by part number and serial number of Table 1 of this AD.

Amendment 2 introduces additional inspection requirements.

The original issue of this AD became effective on 20 June 2001.

Amendment 1 of this AD became effective on 11 May 2006.