# AD 2010-23-20: Gas generator turbine (GGT) shafts

- Type: Airworthiness directive
- Status: Current
- Products: General Electric CT7-9C and CT7-9C3
- Effective: December 22, 2010
- Published: November 17, 2010, 75 FR 70096–70098
- Issued: October 29, 2010
- Issued as: Final rule
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-16509
- Docket: FAA-2010-0732 (https://www.regulations.gov/docket/FAA-2010-0732)
- Project: 2010-NE-04-AD
- Registered aircraft: 75 may be affected, by airframe or engine model (OpenAirDocs)
- Official PDF: https://openairdocs.org/files/sha256/11/ae/11ae599af7675a92d7574c7bac5367c4429460a783fb54e141b5e9f8eb44f2c5 (from https://www.govinfo.gov/content/pkg/FR-2010-11-17/pdf/2010-28449.pdf)
- Federal Register: https://www.federalregister.gov/documents/2010/11/17/2010-28449/airworthiness-directives-general-electric-company-ge-ct7-9c-and--9c3-turboprop-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/C5F904D4DE3F3A00862577DE00567ECE.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/2010-23-20

## Summary

We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires inspecting certain serial number (S/N) gas generator turbine (GGT) shafts for nonconforming land balance-cuts, and if found, removing the shaft from service. This AD was prompted by reports of a manufacturing quality problem. We are issuing this AD to detect nonconforming GGT shaft land balance-cuts, which could result in the shaft failing before its published life limit, and which could result in an uncontained engine failure and damage to the airplane.

## The airworthiness directive

### Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

2010-23-20 General Electric Company (GE): Amendment 39-16509; Docket No. FAA-2010-0732; Directorate Identifier 2010-NE-04-AD.

### (a) Effective Date

  (a) This AD is effective December 22, 2010.

### (b) Affected ADs

  (b) None.

### (c) Applicability

  (c) This AD applies to GE CT7-9C and -9C3 turboprop engines with gas generator turbine (GGT) shafts, part number (P/N) 6068T44P02, that have a serial number (S/N) listed in Table 1 of this AD, installed. These engines are installed on, but not limited to, EADS CASA (formerly Construcciones Aeronauticas, S.A.) CN-235 series airplanes.

*Table 1—Affected GGT Shaft S/Ns*

|  |  |  |  |
| --- | --- | --- | --- |
| Affected Shaft S/Ns |  |  |  |
| GATHHCPC | GATHHJR7 | GATHHJR9 | GATHHKG6 |
| GATHHM9R | GATHHWM3 | GATHJ4ED | GATHJ9FL |
| GATHJ19J | GATHJE8P | GATHJWWR | GATHK0KM |
| GATHK2N1 | GATHK3M3 | GATHK90K | GATHK96D |
| GATHKF9R | GATHKH36 | GATHKMP7 | GATHKRKN |
| NCE715DA |  |  |  |

### (d) Unsafe Condition

  (d) This AD results from reports of a manufacturing quality problem. We are issuing this AD to detect nonconforming GGT shaft land balance-cuts, which could result in the shaft failing before its published life limit, and which could result in an uncontained engine failure and damage to the airplane.

### (e) Compliance

  (e) You are responsible for having the actions required by this AD performed at the first shop visit after the effective date of this AD, or within 5,000 cycles- since-new, whichever occurs first, unless the actions have already been done.

### (f) Inspection for Nonconforming Land Balance-Cuts

  (f) For CT7-9C and -9C3 engines with a GGT shaft, P/N 6068T44P02, that has a S/N listed in Table 1 of this AD, installed, inspect the shaft for nonconforming land balance-cuts. Use the Accomplishment Instructions 3.A.(1) through 3.A.(4) of GE CT7-TP Alert Service Bulletin 72-A0501, Revision 01, dated March 3, 2010, to perform the inspection.

  (g) If you find any nonconforming land balance-cuts, remove the shaft from service.

### (h) Alternative Methods of Compliance

  (h) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19.

### (i) Related Information

    (i) For more information about this AD, contact Walter Meibaum, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone (781) 238-7119; fax (781) 238-7199; e-mail: walter.meibaum@faa.gov.

### (j) Material Incorporated by Reference

  (j) You must use GE CT7-TP Alert Service Bulletin 72-A0501, Revision 01, dated March 3, 2010, to do the actions required by this AD, unless the AD specifies otherwise.

  (1) The Director of the Federal Register approved the incorporation by reference of GE CT7-TP Alert Service Bulletin 72-A0501, Revision 01, dated March 3, 2010, under 5 U.S.C. 552(a) and 1 CFR part 51.

  (2) For service information identified in this AD, contact General Electric Company, GE-Aviation, Room 285, 1 Neumann Way, Cincinnati, Ohio 45215; e-mail geae.aoc@ge.com; telephone (513) 552-3272; fax (513) 552-3329.

  (3) You may review copies of the service information at the FAA, 12 New England Executive Park, Burlington, MA. For information on the availability of this material at the FAA, call (781) 238-7125.

  (4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at an NARA facility, call 202-741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

## Rule preamble

### Dates

This AD is effective December 22, 2010.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of December 22, 2010.

### Addresses

For service information identified in this AD, contact General Electric Company, GE-Aviation, Room 285, 1 Neumann Way, Cincinnati, Ohio 45215; e-mail geae.aoc@ge.com; telephone (513) 552-3272; fax (513) 552-3329. You may review copies of the referenced service information at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA. For information on the availability of this material at the FAA, call (781) 238-7125.

### For further information contact

Walter Meibaum, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone (781) 238-7119; fax (781) 238-7199; e-mail: walter.meibaum@faa.gov.

### Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to the specified products. That NPRM published in the Federal Register on July 23, 2010 (75 FR 43099). That NPRM proposed to require inspecting certain S/N GGT shafts, P/N 6068T44P02, for nonconforming land balance-cuts, and if found, replacing the shaft.

### Comments

We gave the public the opportunity to participate in developing this AD. We received no comments on the NPRM or on the determination of the cost to the public.

### Conclusion

We reviewed the relevant data and determined that air safety and the public interest require adopting the AD as proposed.

### Costs of Compliance

We estimate that this AD affects five engines installed on airplanes of U.S. registry.

We estimate the following costs to comply with this AD:

*Estimated Costs*

| Action | Labor cost | Parts cost | Cost per product | Cost on U.S. operators |
| --- | --- | --- | --- | --- |
| Inspect | 1 work-hour × $85 per hour = $85. |  | $85 | $425 |
| Replace shaft | 1.5 work-hour × $85 per hour = $127.50 | $28,633 | 28,760.50 | 143,802 |
| Total |  |  |  | 144,227 |

### Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

### Regulatory Findings

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

  (1) Is not a “significant regulatory action” under Executive Order 12866,

  (2) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979),

  (3) Will not affect intrastate aviation in Alaska, and

  (4) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS E8NE](https://openairdocs.org/tcds/E8NE): General Electric Company GE Aviation; names 2 of 30 models: CT7-9C, CT7-9C3

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 75 (0 by airframe model, 75 by engine model)
- Makers: Saab-Scania 34, Bell 15, Construcciones Aeronauticas 10, Sikorsky 4, Bell Helicopter Textron 3, Saab-Fairchild 3, Agustawestland 2, Leonardo S P A 2, CASA 1, Saab 1

Models with the most aircraft:

- [GE CT7-SER series](https://openairdocs.org/engine/ge-ct7-ser-series): 43 aircraft (engine model)
- [GE CT7 series](https://openairdocs.org/engine/ge-ct7-series): 26 aircraft (engine model)
- [GE CT7-9C3](https://openairdocs.org/engine/ge-ct7-9c3): 6 aircraft (engine model)

All 3 models: https://openairdocs.org/ad/2010-23-20/models.md
Every aircraft: https://openairdocs.org/ad/2010-23-20/aircraft.md

## Related documents

- [Proposed rule FAA-2010-0732](https://openairdocs.org/proposed/FAA-2010-0732): Notice of proposed rulemaking (NPRM), published Jul 23, 2010

Its text cites no advisory circulars or STCs.

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