01-24271. Airworthiness Directives; Rolls-Royce plc Dart 525, 525F, 528, 528D, 529, 529D, 530, 532, 535, 542, and 552 Series Turboprop Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This amendment adopts a new airworthiness directive (AD) that is applicable to Rolls-Royce plc (RR) Dart 525, 525F, 528, 528D, 529, 529D, 530, 532, 535, 542, and 552 series turboprop engines. This action requires the removal of certain part number (P/N) high pressure turbine (HPT) discs and replacement with serviceable discs. This amendment is prompted by three reports of uncontained HPT disc failures and the manufacturer's investigation into disc failure. The actions specified in this AD are intended to prevent HPT disc failure, which could result in an uncontained engine failure and damage to the airplane.

DATES:

Effective October 15, 2001. Comments for inclusion in the Rules Docket must be received on or before November 27, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2001-NE-29-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: “[e-mail]”. Comments sent via the Internet must contain the docket number in the subject line. The service information referenced in this AD may be obtained from Rolls-Royce plc, P.O. Box 31 Derby, DE24 8BJ, United Kingdom; telephone [phone]; fax [phone]. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Keith Mead, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK), recently notified the FAA that an unsafe condition may exist on RR Dart 525, 525F, 528, 528D, 529, 529D, 530, 532, 535, 542, and 552 series turboprop engines. The CAA advises that three reports of uncontained HPT disc failures have occurred on in-service engines. The results of an investigation reveal that fretting, wear, and open clearance between the HPT disc diaphragm seal arm and intermediate pressure turbine (IPT) disc diaphragm seal arm can result in a high-response disc vibration mode, which results in high-cycle-fatigue (HCF) fractures in the HPT disc. The manufacturer, through testing, has shown that by adding an interference fit between the HPT and IPT seal arms, the discs become effectively preloaded against each other, significantly reducing disc diaphragm vibratory stresses. This condition, if not corrected, could result in HPT disc failure, which could result in an uncontained engine failure and damage to the airplane.

Bilateral Airworthiness Agreement

This engine model is manufactured in the UK, and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

FAA's Determination of an Unsafe Condition and Proposed Actions

Since an unsafe condition has been identified that is likely to exist or develop on other Rolls-Royce plc Dart 525, 525F, 528, 528D, 529, 529D, 530, 532, 535, 542, and 552 series turboprop engines of the same type design, this AD is being issued to prevent HPT disc failure, which could result in an uncontained engine failure and damage to the airplane. This AD requires the scheduled replacement of HPT discs of the affected design with serviceable discs. The cycles and calendar dates of the replacement schedule are based on risk analysis and the need for owners/operators to have an adequate length of time to accomplish this AD.

Immediate Adoption of This AD

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited

Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NE-29-AD.” The postcard will be date stamped and returned to the commenter.

Regulatory Impact

This final rule does not have federalism implications, as defined in Executive Order 13132, because it 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. Accordingly, the FAA has not consulted with state authorities prior to publication of this final rule.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a “significant regulatory action” under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39—AIRWORTHINESS DIRECTIVES

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. Section 39.13 is amended by adding the following new airworthiness directive:

2001-19-06 Rolls-Royce plc: Amendment 39-12446. Docket 2001-NE-29-AD.

Applicability

This airworthiness directive (AD) is applicable to Rolls-Royce Dart 525, 525F, 528-7E, 528D-7E, 529-7E, 529D-7E, 529-7H, 529D-7H, 529-8E, 529D-8E, 529-8H, 529D-8H, 529-8X, 529D-8X, 529-8Y, 529D-8Y, 529-8Z, 529D-8Z, 530, 532-7, 532-7L, 532-7N, 532-7P, 532-7R, 535-2, 535-7R, 542-10, 542-10J, 542-10K, 542-4, 542-4K, 552-2, 552-7, 552-7R series turbofan engines that contain high pressure turbine (HPT) discs having the part numbers listed in the following Table 1:

Table 1.—Part Numbers of Applicable HPT Discs

ARK49431	ARK49434	ARK49437	A.RK50111	A.RK50120
A.RK50121	BRK49431	BRK49434	BRK49437	B.RK50111
B.RK50120	B.RK50121	CRK49431	CRK49434	CRK49437
C.RK50111	C.RK50120	C.RK50121	RK33092	RK33097
RK33099	RK33104	RK33114	RK33117	RK33119
RK33122	RK33125	RK33130	RK33131	RK33214
RK33466	RK33499	RK34206	RK34207	RK34208
RK34209	RK34210	RK34211	RK34212	RK34213
RK34671	RK34674	RK36477	RK36479	RK36481
RK36483	RK36485	RK36487	RK36489	RK36491
RK38592	RK38593	RK38594	RK38595	RK40712
RK40713	RK40714	RK40715	RK40716	RK40717
RK40718	RK40719	RK40720	RK40721	RK40722
RK40723	RK40724	RK40725	RK40726	RK40727
RK43749	RK43750	RK43751	RK44112	RK44113
RK44114	RK44115	RK44116	RK44117	RK44118
RK44119	RK44120	RK44121	RK44122	RK44123
RK44124	RK44125	RK44126	RK44127	RK44310
RK44311	RK44312	RK44328	RK44342	RK44374
RK44397	RK45565	RK46136	RK46485	RK46486
RK46487	RK46488	RK46489	RK46490	RK46491
RK46492	RK46493	RK46494	RK46495	RK46496
RK46497	RK46498	RK46499	RK46531	RK46828
RK48339	RK49121	RK49209	RK49210	RK49211
RK49431	RK49434	RK49437	RK50111	RK50120
RK50121

These engines are installed on, but not limited to BAC Viscount Type 810 aircraft, Fokker F.27 Friendship Mark 200, 400, 500, and 600 series aircraft, Maryland Air Industries, Inc. Fairchild F-27A, F, G, M, J, FH-227, FH-227B, C, D, and E series aircraft, Gulfstream Aerospace Model G-159 aircraft, BAE SYSTEMS (Operations) Limited HS 748 series aircraft, Mitsubishi Heavy Industries, Ltd. YS-11 series aircraft, and Convair CV600/640 series aircraft.

Note 1:

This AD applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance

Compliance with this AD is required as indicated, unless already done.

To prevent HPT disc failure, which could result in an uncontained engine failure and damage to the airplane, do the following:

(a) Remove from service the discs listed by part number in Table 1 of this AD, in accordance with the following Table 2 of this AD:

Table 2.—Removal Schedule

If:	Then:
(1) Engine is fitted with a listed HPT disc with more than 15,000 cycles since new (CSN) on effective date of this AD	Remove from service and replace with a serviceable disc within 300 cycles or before June 30, 2002, whichever occurs earlier.
(2) Engine is fitted with a listed HPT disc that has 12,000 CSN to 15,000 CSN on effective date of this AD	Remove from service and replace with a serviceable disc within 600 cycles or before June 30, 2002, whichever occurs earlier.
(3) Engine is fitted with a listed HPT disc that has 9,000 to 11,999 CSN on effective date of this AD	Remove from service and replace with a serviceable disc within 900 cycles.
(4) Engine is fitted with a listed HPT disc that has more than 6,000 CSN as of June 30, 2003	Before further flight, remove from service and replace with a serviceable disc.
(5) Engine is fitted with a listed HPT disc as of June 30, 2004	Before further flight, remove from service and replace with a serviceable disc.

(b) Remove from service any discs, listed by part number in Table 1 of this AD, from engines that are returned for a shop visit for any reason.

Definitions

(c) For the purpose of this AD, a serviceable disc is one whose P/N is not listed in Table 1 of this AD. Information on the reworking of affected discs into serviceable discs is specified in Rolls-Royce Dart Service Bulletin Da72-533 Revision 2, dated July 25, 2001.

Alternative Methods of Compliance

(d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office (ECO). Operators must submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO.

Special Flight Permits

(e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Note 3:

The subject of this AD is addressed in Civil Airworthiness Authority airworthiness directive AD 007-02-2001, dated April 12, 2001.

Effective Date of this AD

(f) This amendment becomes effective on October 15, 2001.

Issued in Burlington, Massachusetts, on September 20, 2001.

Jay J. Pardee,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.