AD 99-04-09

This amendment adopts a new airworthiness directive (AD) that is applicable to Rolls-Royce Limited (R-R) Dart series turboprop engines. This action requires initial and repetitive fuel burner fuel flow calibration checks, and overhaul or replacement of fuel burners. This amendment is prompted by reports of an uncontained engine failure and fire due to HPT disk rupture caused by fuel burner failure. The actions specified in this AD are intended to prevent HPT disk rupture, which can result in an uncontained engine failure, engine fire, and damage to the aircraft.
The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of February 25, 1999.
Comments for inclusion in the Rules Docket must be received on or before April 12, 1999.

Final rule; request for comments.

99-04-09 Rolls-Royce Limited: Amendment 39-11033. Docket 98-ANE-46-AD.
Applicability: Rolls-Royce Limited (R-R) Dart 525 series, 526, 527, 528 series, 529 series, 530, 531, 532 series, 535 series, 542 series, and 552 series turboprop engines, installed on but not limited to Gulfstream Aerospace Corp. G-159, British Aerospace HS 748, Fokker Aircraft F27, Fairchild Hiller FH227, Mitsubishi Heavy Industries YS-11, General Dynamics (Convair) 640 and 600 series, and Vickers Armstrong (Aircraft Limited) Viscount aircraft.
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 (e) 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 high pressure turbine (HPT) disk rupture, which can result in an uncontained engine failure, engine fire, and damage to the aircraft, accomplish the following:
(a) For engines with a complete set of HPT blades that were either inspected and reworked to D.R.S. 611 standard or were installed new at last HPT rework or engine overhaul, perform fuel burner fuel flow calibration checks and overhaul or replacement of fuel burners in accordance with R-R Alert Service Bulletin (ASB) No. Da73-A87, dated May 1998, at each engine overhaul, or prior to exceeding 3,000 hours time in service (TIS) since last fuel burner calibration, whichever occurs first.
(b) Inspection to the D.R.S. 611 standard requires the HPT blades to have both the inner platform and shroud inspected to this standard. This inspection requirement was added to the Engine Overhaul Manual in 1992. Inspection to the D.R.S. 611 standard prior to this date must be considered to be pre-D.R.S. 611 standard.
(c) For engines with HPT blades that have not been inspected and modified during the last engine or HPT overhaul using the D.R.S. 611 build standard, perform initial and repetitive fuel burner fuel flow calibration checks and overhaul or replacement of fuel burners in accordance with R-R ASB No. Da73-A87, dated May 1998, as follows:
(1) For engines with 6,000 or more hours time in service (TIS) since last HPT overhaul and rework, perform the initial check and overhaul as follows:
(i) For fuel burners with more than 850 hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding an additional 150 hours TIS after the effective date of this AD, but not to exceed 1,000 hours TIS since last fuel burner calibration after June 30, 1999.
(ii) For fuel burners with 850 or less hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding 1,000 hours TIS since last fuel burner calibration.
(2) For engines with 5,000 or more hours but less than 6,000 hours TIS since last HPT overhaul and rework, perform the initial check and overhaul as follows:
(i) For fuel burners with more than 700 hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding an additional 300 hours TIS after the effective date of this AD, but not to exceed 1,000 hours TIS since last fuel burner calibration after June 30, 1999.
(ii) For fuel burners with 700 or less hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding 1,000 hours TIS since last fuel burner calibration.
(3) For engines with 4,000 or more hours but less than 5,000 hours TIS since last HPT overhaul and rework, perform the initial check and overhaul as follows:
(i) For fuel burners with more than 550 hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding an additional 450 hours TIS after the effective date of this AD, but not to exceed 1,000 hours TIS since last fuel burner calibration after June 30, 1999.
(ii) For fuel burners with 550 or less hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding 1,000 hours TIS since last fuel burner calibration.
(4) For engines with less than 4,000 hours TIS since last HPT overhaul and rework, perform the initial check and overhaul as follows:
(i) For fuel burners with more than 100 hours TIS since last fuel burner calibration, performthe fuel flow check and calibration prior to exceeding an additional 900 hours TIS after the effective date of this AD, but not to exceed 1,000 hours TIS since last fuel burner calibration after June 30, 1999.
(ii) For fuel burners with 100 or less hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding 1,000 hours TIS since last fuel burner calibration.
(5) Thereafter, perform repetitive fuel burner fuel flow calibration checks and overhauls at intervals not to exceed 1,000 hours TIS since last fuel burner fuel flow calibration check.
(d) After the effective date of this AD, no new fuel burner may be installed unless it has been subject to a satisfactory fuel flow calibration check within 3 years prior to installation, and no fuel burner run since last overhaul, including those fitted to a combustion chamber, may be installed unless it has been subject to a satisfactory fuel flow calibration check in accordanceto R-R ASB Da 73-A87, dated May 1998, prior to installation.
(e) 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.
(f) 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 aircraft to a location where the requirements of this AD can be accomplished.
(g) The actions required by this AD shall be performed in accordance with the following R-R ASB:

Document No.
Pages
Date
Da73-A87
1-8
May 1998
Total pages: 8.

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 Rolls-Royce Limited, Attn.: Dart Engine Service Manager, East Kilbride, Glasgow G74 4PY, Scotland. 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 February 25, 1999.

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK), recently notified the Federal Aviation Administration (FAA) that an unsafe condition may exist on Rolls-Royce Limited (R-R) Dart 525 series, 526, 527, 528 series, 529 series, 530, 531, 532 series, 535 series, 542 series, and 552 series turboprop engines. The CAA advises that they have received a report of an uncontained engine failure and subsequent fire shortly after takeoff. The investigation revealed that the high pressure turbine (HPT) disk had failed resulting in the release of a section of rim and diaphragm from the disk. The cause of the HPT disk failure was attributed to high cycle fatigue (HCF) induced by a once-per-revolution resonance force resulting from fuel burner malfunction. This condition, if not corrected, could result in HPT disk rupture, which can result in an uncontained engine failure, engine fire, and damage to the aircraft.
R-R has issued Alert Service Bulletin (ASB) No. Da73-A87, dated May 1998, that specifies procedures for fuel burner fuel flow calibration checks and overhaul of fuel burners. The CAA classified the ASB as mandatory and issued CAA AD 002-05-98 in order to assure the airworthiness of these engines in the UK.
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.
Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design installed on aircraft registered in the United States, this AD requires initial and repetitive fuel burner fuel flow calibration checks, and overhaul or replacement of fuel burners. The fuel burner fuel flow calibration checks, and overhaul or replacement of fuel burners must be performed in accordance with the schedule specified in the compliance section. The schedule was determined based upon R-R risk analysis, and parts and overhaul facility availability.
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 personsare 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 notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-ANE-46-AD." The postcard will be date stamped and returned to the commenter.
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.
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, Incorporation by reference, 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: 49U.S.C. 106(g), 40113, 44701. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: