AD 98-24-03 R1

This amendment revises an existing airworthiness directive (AD), applicable to BMW Rolls-Royce GmbH (BRR) Models BR700-710A1-10 and BR700-710A2-20 turbofan engines. The existing AD requires initial and repetitive visual inspections of the engine compressor and combustion core fairings (also referred to as the engine core fairings) and fasteners for correct installation and damage, and verification that the engine core fairing fasteners are torqued to a higher torque value. This amendment increases the repetitive inspection interval to 150 hours time-in-service (TIS) following an initial inspection and follow-on inspection at the current 50 hours TIS interval. This amendment also requires an initial inspection and follow-on inspection at a 50 hours TIS interval following any engine core fairing or fastener removal, repair, or replacement. Repair of engine core fairings has been added as an alternate to engine core fairing replacement, and an inspection for loose engine core fairing(s) has been included to verify correct installation on the engine. Finally, this amendment adds a new paragraph in the compliance section allowing the option to incorporate redesigned core engine fairings as the terminating action to the required repetitive inspections. This amendment is prompted by results of repetitive inspections that indicate that the inspection interval can be increased safely, and by introduction of redesigned engine core fairings. The actions specified by this AD are intended to prevent engine compressor or combustion core fairing detachment and damage to the engine bypass duct, resulting in engine failure and damage to the airplane.

Final rule; request for comments.

98-24-03 R1 BMW ROLLS-ROYCE GmbH: Amendment 39-11425. Docket 98-ANE-74-AD. Revises AD 98-24-03, Amendment 39-11050. Issued November 5, 1999.
Applicability: BMW Rolls-Royce GmbH (BRR) Model BR700-710A1-10 and BR700-710A2-20 turbofan engines installed on, but not limited to, Gulfstream Aerospace G-V and Bombardier BD-700-1A10 series airplanes.
Note 1: This airworthiness directive (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 (f) 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: Required as indicated, unless accomplished previously.
To prevent engine compressor and combustion core fairing (also referred to as the engine core fairing) detachment which could result in damage to the engine bypass duct, engine failure and damage to the aircraft, accomplish the following: Inspections, Repair, Replacement, and Torquing
(a) Prior to further flight, visually inspect the engine core fairings and fasteners to ensure correct installation and for cracks, loose fairings, or fasteners, and if loose, cracked, damaged, or improperly installed, repair or replace with serviceable parts. Torque all the fasteners to the increased torque value, in accordance with BRR Service Bulletin (SB) R700-72-900062, Revision 1, dated October 29, 1998, or Revision 2, dated November 3, 1998, or Revision 3, dated March 24, 1999.
(b) Thereafter, except as provided in paragraphs (c) or (d) of this AD, at intervals not to exceed 50 hours time-in-service (TIS) since last inspection, visually inspect the engine core fairings and fasteners for cracks, loose fairings, or fasteners, and, if loose, cracked, or damaged, repair or replace with serviceable parts. Torque all the fasteners to the increased torque value, in accordance with BRR SB BR700-72-900062, Revision 2, dated November 3, 1998, or Revision 3, dated March 24, 1999.
(c) Following an initial inspection in accordance with paragraph (a) of this AD, and one follow-on inspection in accordance with paragraph (b), if both inspections found no cracks, damage, loose fairings or fasteners the repetitive inspection interval may be increased to 150 hours TIS since last inspection in accordance with the procedures described in paragraph (b) of this AD.
(d) Reinspection and retorquing prior to further flight is required in accordance with paragraph (a) of this AD, following any engine core fairing or fastener which has been removed, repaired or replaced. One successful follow-on inspection and retorque in accordance with paragraph (b) of this AD must be accomplished before the repetitive 150 hour TIS inspection interval described in paragraph (c) of this AD is permitted.
Optional Terminating Action
(e) Incorporation of the redesigned engine core fairings in accordance with BRR SB BR700-72-100900, Revision 1, dated September 10, 1999, constitutes terminating action for the requirements specified in paragraphs (a), (b), (c), and (d) of this AD.
Alternative Methods of Compliance
(f) 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. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.
Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
Incorporation by Reference
(g) The actions required by this AD shall be done in accordance with the following BRR SBs: BR700-72-900062, Revision 1, dated October 29, 1998; Revision 2, dated November 3, 1998; Revision 3, dated March 24, 1999; and BR700-72-100900, Revision 1, dated September 10, 1999. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from BMW Rolls-Royce GmbH, Eschenweg 11, D-15827 Dahlewitz, Germany; telephone 011-49-33-7086-1883; fax 011-49-33-7086-3276. Copies may be inspected 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.(h) This amendment becomes effective on December 27, 1999.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by revising Airworthiness Directive (AD) 98-24-03, Amendment 39-11050 (64 FR 9056, February 24, 1999), following a priority letter AD issued November 12, 1998, which is applicable to BMW Rolls-Royce GmbH (BRR) Models BR700-710A1- 10 and BR700-710A2-20 turbofan engines, was published in the Federal Register on August 17, 1999 (64 FR 44666). The action proposed to increase the repetitive inspection interval to 150 hours time-in-service (TIS) following an initial inspection and follow-on inspection at the current 50 hours TIS interval. This action also proposed to require an initial inspection and follow-on inspection at a 50 hours TIS interval following any engine core fairing or fastener removal, repair, or replacement. Repair of engine core fairings would be added as an alternate to engine core fairing replacement, and an inspection for loose engine core fairing(s) would be included to verify correct installation on the engine. That action was prompted by results of repetitive inspections that indicate that the inspection interval can be increased safely. That condition, if not corrected, could result in engine compressor or combustion core fairing detachment and damage to the engine bypass duct, resulting in engine failure and damage to the airplane.
No Comments Received
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public.
Optional Terminating Action
Since publication of the NPRM, BRR has issued Service Bulletin (SB) BR700-72-100900, Revision 1, dated September 10, 1999 which introduces redesigned engine core fairings thereby allowing the option to incorporate this redesigned hardware as the terminating action to the required repetitive inspections. The Luftfahrt-Bundesamt (LBA), the airworthiness authority for Germany, has reviewed and approved the technical contents of this SB.
Difference Between NPRM and Final Rule
Except for the optional terminating action, there is no change between the proposal and this final rule.
Bilateral Airworthiness Agreement
This engine model is manufactured in Germany 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 LBA has kept the FAA informed of the situation described above. The FAA has examined the findings of the LBA, 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
Economic Analysis
There exists no adverse economic impact because this revised rule only increases the repetitive inspection interval. However, if an operator chooses to install the new engine core fairings, the labor is approximately 25 work hours at the average labor rate of $60 per work hour. Required parts are approximately $141,372. The total cost per engine of the new engine core fairings is $142,872. The manufacturer has advised the FAA that they may lower the economic burden on operators by reimbursing the costs associated with the incorporation of the redesigned engine core fairings.
Adoption of the Rule
After careful review of the available data, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously.
Comments Invited
Since the optional terminating action involving installation of new engine core fairings was not in the NPRM, comments are invited from the public on this option and its economic impact. 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 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 receiptof their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-ANE-74-AD." The postcard will be date stamped and returned to the commenter.
Regulatory Impact
The regulations adopted herein will not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (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); and (3) 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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, Incorporation by reference, Safety.