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Proposed Rule

Airworthiness Directives; Pratt & Whitney JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, -17AR, -209, -217, -217A, -217C, and -219 Turbofan Engines

Action

Notice Of Proposed Rulemaking (Nprm).

Summary

The FAA proposes to supersede an existing airworthiness directive (AD) for Pratt Whitney (PW) JT8D-209, -217, -217A, -217C, and -219 turbofan engines. That AD currently requires initial and repetitive visual inspections for fretting and fluorescent magnetic particle inspections (FMPI) for cracking in the area of the tierod holes on 8th stage high pressure compressor (HPC) front hubs (from here on, referred to as HPC front hubs) that have operated at any time with PWA 110-21 coating. This proposed AD would require either replacing HPC front hubs and HPC disks that have operated at any time with PWA 110-21 coating and that operated in certain engine models, or, visually inspecting and FMPI for cracking of those parts and replating them if they pass inspection. This proposed AD would also require adding JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, 17A, 17R, and 17AR engines to the applicability. This proposed AD results from an investigation by PW, which concluded that any HPC front hub or HPC disk coated with PWA 110-21 that ever operated on JT8D-15, -15A, -17, -17A, -17R, -17AR, -209, -217, -217A, -217C, and -219 turbofan engines, could crack before reaching their published life limit. We are proposing this AD to prevent a rupture of an HPC front hub or an HPC disk that could result in an uncontained engine failure and damage to the airplane.

Unified Agenda

Airworthiness Directives

1 action from November 2013

  • November 2013
    • Actions Will Continue Through
 

Table of Contents Back to Top

Tables Back to Top

DATES: Back to Top

We must receive any comments on this proposed AD by February 28, 2006.

ADDRESSES: Back to Top

Use one of the following addresses to comment on this proposed AD:

  • By mail: Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2001 NE-30-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
  • By fax: (781) 238-7055.
  • By e-mail: 9-ane-adcomment@faa.gov.

Contact Pratt Whitney, 400 Main St., East Hartford, CT 06108, telephone (860) 565-7700; fax (860) 565-1605 for the service information identified in this proposed AD.

You may examine the AD docket at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Back to Top

Keith Lardie, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7189; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: Back to Top

Comments Invited Back to Top

We invite you to send us any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. 2001-NE-30-AD” in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it; we will date-stamp your postcard and mail it back to you. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. If a person contacts us verbally, and that contact relates to a substantive part of this proposed AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

Examining the AD Docket Back to Top

You may examine the docket that contains the proposal, any comments received and any final disposition by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. See ADDRESSES for the location.

Discussion Back to Top

On November 15, 2002, we issued AD 2002-23-14, Amendment 39-12958 (67 FR 70686, November 26, 2002). That AD requires initial and repetitive visual inspections for fretting and FMPI for cracking in the area of the tierod holes on HPC front hubs that have operated at any time with PWA 110-21 coating. That AD resulted from the discovery of cracking in the area of the tierod holes, found during routine engine overhauls. That condition, if not corrected, could result in an uncontained engine failure and damage to the airplane.

Actions After We Issued AD 2002-23-14 Back to Top

After we issued AD 2002-23-14, PW completed their investigation to determine the cause of cracking in the area of the tierod holes on HPC front hubs. As part of that investigation, PW looked at seven HPC front hubs coated with PWA 110-21. They found fretting, cracks, or both, at the rear bolt face of the HPC front hub on six of the seven HPC front hubs. This was similar to the cracks seen in PW's initial investigation into this issue. Most of the seven hubs had low cycle time, with the lowest being 2,800 cycles-since-new. Additional cracks were found on other stages of HPC disks, both with nickel-cadmium, and PWA 110-21 coating. PW determined that all HPC front hubs and HPC disks that have ever been coated with PWA 110-21 and that have ever been operated on JT8D-15, -15A, -17, -17A, -17R, -17AR, -209, -217, -217A, -217C, and -219 turbofan engines, have a higher risk of fracturing before reaching their published life limit of 20,000 cycles-in-service, than HPC front hubs and HPC disks plated with nickel-cadmium.

Relevant Service Information Back to Top

We have reviewed and approved the technical contents of PW Alert Service Bulletin (ASB) No. JT8D A6430, Revision 2, dated December 23, 2004, applicable to JT8D-209, -217, -217A, -217C, and -219 turbofan engines, and PW ASB No. JT8D A6468, dated December 23, 2004, applicable to JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR turbofan engines. Those ASBs describe procedures for visual inspections for fretting wear and FMPI for cracking of HPC front hubs that have operated with PWA 110-21 coating in the interface between the HPC front hub and the stage 8-9 spacer. Those ASBs also describe procedures for replating HPC front hubs using nickel-cadmium, and replating stage 8-9 spacers using nickel-cadmium or electroless nickel.

Differences Between the Proposed AD and the Manufacturer's Service Information Back to Top

Although the ASBs only require inspection of the HPC front hubs and stage 8-9 spacers, we propose to require inspecting all 7th stage HPC disks and 9th stage-through-12th stage HPC disks for fretting wear and FMPI for cracking at the same time the HPC front hub is visually inspected. These other HPC disks, which are coated with PWA 110-21, have increased risk of cracking and failure.

FAA's Determination and Requirements of the Proposed AD Back to Top

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. We are proposing this AD, which would require:

  • Visual inspections for fretting wear and FMPI of HPC front hubs, HPC disks, and stage 8-9 spacers that at any time operated coated with PWA 110-21, replacing them if necessary; replating those HPC front hubs and disks using nickel-cadmium, and replating stage 8-9 spacers using nickel-cadmium or electroless nickel;

OR

  • As optional terminating action to the visual inspections in the proposed AD, replacing HPC front hubs, HPC disks, and stage 8-9 spacers that at any time operated coated with PWA 110-21 in JT8D-15, -15A, -17, -17A, -17R, -17AR, -209, -217, -217A, -217C, or -219 turbofan engines.
  • Replacement must be with HPC front hubs and HPC disks plated with nickel-cadmium that have never operated with PWA 110-21 coating, and stage 8-9 spacers plated with nickel-cadmium or electroless nickel.

The proposed AD would require that you do these actions using the service information described previously.

Costs of Compliance Back to Top

About 1,573 JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR turbofan engines, and 1,280 JT8D-200 series turbofan engines, installed on airplanes of U.S. registry would be affected by this proposed AD. We estimate it would take about 12 work hours per engine to perform the proposed actions, and the average labor rate is $65 per work hour. We also estimate 175 of those engines would be removed before reaching scheduled maintenance, and would require an additional 60 work hours to disassemble and reassemble each engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $2,907,840.

Authority for This Rulemaking Back to Top

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 Back to Top

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 the proposed regulation:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 110-2134, February 26, 1979); and

3. Would not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

We prepared a summary of the costs to comply with this proposal and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “AD Docket No. 2001-NE-30-AD” in your request.

List of Subjects in 14 CFR Part 39 Back to Top

The Proposed Amendment Back to Top

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 14 CFR part 39 as follows:

begin regulatory text

PART 39—AIRWORTHINESS DIRECTIVES Back to Top

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

Authority:

49 U.S.C. 106(g), 40113, 44701.

§ 39.13 [Amended]

2. The FAA amends § 39.13 by removing Amendment 39-12958 (67 FR 70686, November 26, 2002) and by adding a new airworthiness directive to read as follows:

Pratt Whitney: Docket No. 2001-NE-30-AD.

Comments Due Date Back to Top

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by February 28, 2006.

Affected ADs Back to Top

(b) This AD supersedes AD 2002-23-14, Amendment 39-12958.

Applicability Back to Top

(c) This AD applies to all Pratt Whitney (PW) JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, -17AR, -209, -217, -217A, -217C, and -219 turbofan engines, with 8th stage high pressure compressor (HPC) front hubs (from here on, referred to as HPC front hubs) as defined in the following Table 1:

Table 1.—AD Applicability Back to Top
If: And the HPC front hub: Then this AD is:
(1) The HPC front hub at any time operated coated with PWA 110-21. Operated in a JT8D-15, -15A, -17, -17R, -17AR, -209, -217, -217A, -217C, or -219 engine. Applicable.
(2) The HPC front hub at any time had coating in the interface between the HPC front hub and the stage 8-9 spacer (PWA 110-21 coating applied to spacer). Operated in a JT8D-209, -217, -217A, -217C, or -219 engine. Applicable.
(3) The HPC front hub and HPC disks have PWA 110-21 coating. Operated in a JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, or -11 engine, but never operated in a JT8D-15, -15A, -17, -17A, -17R, -17AR, -209, -217, -217A, -217C, or -219 engine. Not applicable.
(4) The HPC front hub has never operated with PWA 110-21 coating in the interface with the stage 8-9 spacer, either on the HPC front hub or on the stage 8-9 spacer. Not applicable.

These engines are installed on, but not limited to, Boeing DC-9, MD-80 series, 727 series, and 737 series airplanes.

Unsafe Condition Back to Top

(d) This AD results from an investigation by PW, which concluded that any HPC front hub or HPC disk coated with PWA 110-21 that ever operated on JT8D-15, -15A, -17, -17A, -17R, -17AR, -209, -217, -217A, -217C, and -219 turbofan engines, could crack before reaching their published life limit. We are issuing this AD to prevent a rupture of an HPC front hub or an HPC disk that could result in an uncontained engine failure and damage to the airplane.

Compliance Back to Top

(e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.

JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR Turbofan Engines—Inspect or Replace HPC Front Hubs, HPC Disks, and Stage 8-9 Spacers Back to Top

(f) For JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR turbofan engines, do the following:

(1) Using the inspection schedule in Table 2 of this AD, strip the protective coating, visually inspect for fretting wear, fluorescent magnetic particle inspect (FMPI) for cracks, reidentify, replate HPC front hubs and stage 8-9 spacers, and replace if necessary.

(2) Use paragraphs 1 through 3.B.(7)(b) under “For Rear Compressor Front Hubs that Have Operated With PWA 110-21 coating AT ANY TIME During Their Service Life in JT8D-15, -15A, -17, -17A, -17R, -17AR Engine Models.” of PW Alert Service Bulletin (ASB) JT8D A6468, dated December 23, 2004.

Table 2.—HPC Disk Inspection Schedule Back to Top
HPC front hub cycles-since-new (CSN) on the effective date of this AD Inspect before additional cycles-in-service (CIS) or CSN, whichever occurs first Also inspect 7th stage HPC disks and 9th stage-through-12th stage HPC disks using:
(i) 19,000 or more 500 CIS or 20,000 CSN Paragraph (f)(3) of this AD
(ii) 15,500 or more, but fewer than 19,000. 1,000 CIS or 19,500 CSN. Paragraph (f)(3) of this AD.
(iii) Fewer than 15,500. 5,000 CIS or 16,500 CSN. Paragraph (f)(3) of this AD.
(iv) Fewer than 5,000 that are accessible. Paragraph (f)(3) of this AD. If the parts pass inspection, parts may be reinstalled. Inspect again using the criteria listed in (iii) of this Table.

(3) When the HPC front hub is inspected, visually inspect for fretting wear and FMPI for cracks on 7th stage HPC disks and 9th stage-through-12th stage HPC disks. Inspection information can be found in the applicable sections of JT8D Engine Manual Part Number (P/N) 481672, listed in the following Table 3:

Table 3.—7th Stage HPC Disks and 9th Stage-Through-12th Stage HPC Disks Inspection Information Back to Top
Stage Chapter/Section Visual inspection Fretting inspection FMPI
7 72-36-41 Inspection-01 Inspection-04 Inspection-03.
9 72-36-43 Inspection-01 Inspection-04 Inspection-03.
10 72-36-44 Inspection-01 Inspection-04 Inspection-03.
11 72-36-45 Inspection-01 Inspection-04 Inspection-03.
12 72-36-46 Inspection-01 Inspection-04 Inspection-03.

JT8D-15, -15A, -17, -17A, -7R, and -17AR Turbofan Engines—Cycle Adjustment for HPC Front Hubs That Entered Service With Nickel-Cadmium Plating and PWA 110-21 Coating Back to Top

(g) For JT8D-15, -15A, -17, -17A, -17R, and -17AR turbofan engines with front hubs that entered service with nickel-cadmium plating and PWA 110-21 coating, but have also operated during the life of the hub with PWA 110-21 coating:

(1) You are allowed to make a cycle adjustment if the hub was never operated with a PWA 110-21-coated stage 8-9 spacer.

(2) Use the information under “Compliance” of PW ASB JT8D A6468, dated December 23, 2004, to determine the adjustment.

JT8D-209, -217, -217A, -217C, and -219 Turbofan Engines—Inspect or Replace HPC Front Hubs and Stage 8-9 Spacers Back to Top

(h) For JT8D-209, -217, -217A, -217C, and -219 turbofan engines, do the following:

(1) Using the inspection schedule in Table 4 of this AD, strip the protective coating, visually inspect for fretting wear, FMPI for cracking, reidentify, replate HPC front hubs and the stage 8-9 spacers, and replace if necessary.

(2) Use paragraphs 1. through 1.A. and paragraphs 2 through 2.C.(2)(g)2 of Accomplishment Instructions of PW ASB JT8D A6430, Revision 2, dated December 23, 2004.

Table 4.—HPC Disk Inspection Schedule Back to Top
HPC front hub CSN on the effective date of this AD Inspect before additional CIS or CSN, whichever occurs first Also inspect 7th stage HPC disks and 9th stage-through-12th stage HPC disks using:
(i) 19,000 or more 500 CIS or 20,000 CSN Paragraph (h)(3) of this AD.
(ii) 15,500 or more, but fewer than 19,000 1,000 CIS or 19,500 CSN Paragraph (h)(3) of this AD.
(iii) Fewer than 15,500 5,000 CIS or 16,500 CSN Paragraph (h)(3) of this AD.
(iv) Fewer than 5,000 that are accessible Paragraph (h)(3) of this AD. If the parts pass inspection, parts may be reinstalled. Inspect again using the criteria listed in (iii) of this Table.

(3) When the HPC front hub is inspected, visually inspect for fretting wear and FMPI for cracks on 7th stage HPC disks and 9th stage through 12th stage HPC disks. Inspection information can be found in the applicable sections of JT8D-200 Engine Manual P/N 773128, listed in Table 3 of this AD.

JT8D-209, -217, -217A, -217C, and -219 Turbofan Engines—Cycle Adjustment for HPC Front Hubs That Entered Service With Nickel-Cadmium Plating and PWA 110-21 Coating Back to Top

(i) For JT8D-209, -217, -217A, -217C, and -219 turbofan engines with HPC front hubs that entered service with nickel-cadmium plating, but have also operated during the life of the hub with PWA 110-21 coating:

(1) You are allowed to make a cycle adjustment.

(2) Use the information under “CONDITION A” of PW ASB JT8D A6430, Revision 2, dated December 23, 2004, to determine the adjustment.

Replacement of HPC Front Hubs and Stage 8-9 Spacers That Have Operated With PWA 110-21 Coating, As Optional Terminating Action—All Engines Back to Top

(j) For all applicable engines, as optional terminating action for the repetitive visual inspections in this AD, replace HPC front hubs and stage 8-9 spacers that have operated with PWA 110-21 coating in the interface between the hub and the stage 8-9 spacer and HPC disks currently coated with PWA 110-21, as follows:

(1) Install a nickel-cadmium plated HPC front hub that has never operated with PWA 110-21 coating in the interface between the HPC front hub and the stage 8-9 spacer.

(2) Install a nickel-cadmium plated or electroless nickel-plated stage 8-9 spacer.

(3) Install HPC disks that have never operated with PWA 110-21 coating.

Prohibition Against Recoating the HPC Front Hub, Stage 7 HPC Disk, and Stage 8-9 Spacer With PWA 110-21—All Engines Back to Top

(k) Do not recoat the HPC front hub with PWA 110-21 (Repair-23 of Chapter/Section 72-36-42 of JT8D-200 Engine Manual, P/N 773128, and Repair-27 and Repair-28 of Chapter/Section 72-36-42 of JT8D Engine Manual, P/N 481672).

(l) Do not recoat the 7th stage disk with PWA 110-21 (Repair-15 of Chapter/Section 72-36-41 of JT8D-200 Engine Manual, P/N 773128, and Repair-15 of Chapter/Section 72-36-41 of JT8D Engine Manual, P/N 481672).

(m) Do not recoat the stage 8-9 spacer with PWA 110-21 (Repair-03, Task 72-36-12-30-003-002, of Chapter/Section 72-36-12 of JT8D-200 Engine Manual, P/N 773128, and Repair-01, Task 72-36-12-30-001-002, of Chapter/Section 72-36-12 of JT8D Engine Manual, P/N 481672).

Definitions Back to Top

(n) For the purposes of this AD, a shop visit is an engine removal, where engine maintenance entails separating pairs of major engine flanges or removing a disk, hub, or spool at a maintenance facility, regardless of other planned maintenance, except as follows:

(1) Removing the engine to perform field maintenance type activities at a maintenance facility in lieu of performing them on-wing is not a “shop visit.”

(2) Separating flanges of the Combustion Chamber and Turbine Fan Duct Assembly (split flanges) to access non-rotating accessory hardware is not a “shop visit.”

(3) Separating flanges to ship the engine without subsequent internal maintenance is not a “shop visit.”

(o) For the purposes of this AD accessibility of the HPC front hub is removing the hub from the engine and deblading that hub.

Alternative Methods of Compliance Back to Top

(p) 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.

Related Information Back to Top

(q) None.

Issued in Burlington, Massachusetts, on December 23, 2005.

Carlos Pestana,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.

end regulatory text

[FR Doc. E5-8099 Filed 12-29-05; 8:45 am]

BILLING CODE 4910-13-P

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