03-4057. Airworthiness Directives; Rolls-Royce RB211 Series Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

SUMMARY:

This notice revises an earlier proposed airworthiness directive (AD), applicable to Rolls-Royce (RR) plc RB211-535E4-37, RB211-535E4-B-37, and RB211-535E4-B-75 series turbofan engines. That proposal would have required initial and repetitive ultrasonic inspections of low pressure compressor (LPC) fan blade roots for cracks, and relubrication of LPC fan blades before reinstallation. That proposal was prompted by the discovery of cracks on LPC fan blade roots during an engine overhaul. This action revises the proposed rule by introducing an alternative technique to ultrasonically inspect installed fan blades on-wing using a surface wave ultrasonic probe. This action also adds the application of Metco 58 blade root coating as an optional terminating action. The actions specified by this proposed AD are intended to detect cracks in LPC fan blade roots, which if not detected, could lead to uncontained multiple fan blade failure, and damage to the airplane.

DATES:

Comments must be received by April 21, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2000-NE-13-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may be inspected at this location, by appointment, between 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. 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 the proposed rule may be obtained from Rolls-Royce plc, PO Box 31, Derby, England, DE248BJ; telephone: [phone]; fax: [phone]. This information may be examined, by appointment, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT:

James Lawrence, 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:

Comments Invited

Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal 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 2000-NE-13-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRM's

Any person may obtain a copy of this NPRM by submitting a request to the FAA, New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2000-NE-13-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to RR plc RB211-535E4-37, RB211-535E4-B-37, and RB211-535E4-B-75 series turbofan engines, was published as an NPRM in the Federal Register on August 9, 2001 (66 FR 41808). That NPRM would have required initial and repetitive ultrasonic inspections of LPC fan blade roots for cracks, and relubrication of LPC fan blades before reinstallation. That NPRM was prompted by the discovery of cracks on LPC fan blade roots during an engine overhaul. That condition, if not corrected, could result in uncontained multiple fan blade failure, and damage to the airplane.

The FAA received the following comments on the initial NPRM. The latest revision to RR Mandatory Service Bulletin (MSB) RB.211-72-C879, Revision 3, dated October 9, 2002, addresses those comments.

Two commenters request the incorporation of Metco 58 blade root coating as a terminating action to the AD inspection requirements.

The FAA agrees. The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK), has notified the FAA that incorporation of Metco 58 blade root coating using RR Service Bulletin (SB) RB.211-72-C946, dated August 6, 2002, is considered a terminating action to the inspections. The FAA has examined the information provided by RR and the CAA and agrees with the conclusions. Incorporation of Metco 58 blade root coating has been added to the proposed AD as a terminating action.

One commenter requests a draw down inspection schedule for engines that have not previously had repetitive inspections. The commenter states that due to the age of its fleet, it would be difficult to do repetitive inspections in accordance with the AD.

The FAA does not agree with the request due to the potential safety hazard associated with a possible multiple fan blade release. However, RR MSB RB211-72-C879, Revision 3, dated October 9, 2002, allows an alternative on-wing ultrasonic inspection method.

Since the above comments expand the scope of the originally proposed rule, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.

Manufacturer's Service Information

RR has issued MSB RB.211-72-C879, Revision 3, dated October 9, 2002, that specifies ultrasonic inspection of high cyclic life blades on-wing with either the LPC fan blades in place or removed from the LPC. The CAA classified this service bulletin as mandatory and issued AD 002-01-2000 in order to ensure the airworthiness of these RR engines in the UK.

Bilateral Agreement Information

These engines are manufactured in the United Kingdom (UK), and are 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 RR RB211-535E4 series turbofan engines of the same type design, that are used on Boeing 757 airplanes registered in the United States, the proposed AD would require initial and repetitive ultrasonic inspections of LPC fan blade roots on-wing and during overhaul, and relubrication, according to accumulated life cycles.

Economic Analysis

There are approximately 1,021 engines of the affected design in the worldwide fleet. The FAA estimates that 545 engines installed on aircraft of U.S. registry would be affected by this proposed AD. It will take approximately 7.0 work hours per engine to conduct an on-wing initial inspection, and 2 hours per engine to do an overhaul initial inspection of the proposed actions. The average labor rate is $60 per work hour. Since the actions are inspections, there are no required parts costs. Based on these figures, the FAA estimates the total cost for on-wing initial inspections only, of the proposed AD on U.S. operators, to be $228,900, and for overhaul initial inspections only, to be $65,400.

Regulatory Analysis

This proposed 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 proposed rule.

For the reasons discussed above, I certify that this 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 11034, February 26, 1979); and (3) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting 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

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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: Rolls-Royce plc: Docket No. 2000-NE-13-AD.

Applicability

This airworthiness directive (AD) is applicable to Rolls-Royce (RR) plc RB211-535E4-37, RB211-535E4-B-37, and RB211-535E4-B-75 series turbofan engines with low pressure compressor (LPC) fan blades with the part numbers (P/N's) listed in the following Table 1 of this AD. These engines are installed on, but not limited to Boeing 757 and Tupolev Tu204 series airplanes. Table 1 follows:

Table 1.—Applicable LPC Fan Blade P/N's

UL16135	UL16171	UL16182	UL19643	UL20044
UL20132	UL20616	UL21345	UL22286	UL23122
UL24525	UL24528	UL24530	UL24532	UL24534
UL27992	UL28601	UL28602	UL29511	UL29556
UL30817	UL30819	UL30933	UL30935	UL33707
UL33709	UL36992	UL37090	UL37272	UL37274
UL37276	UL37278	UL38029	UL38032

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 (g) 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 detect cracks in LPC fan blade roots, which if not detected, could lead to uncontained multiple fan blade failure, and damage to the airplane, do the following:

(a) If you have a full set of fan blades, modified using RR SB RB.211-72-C946, dated August 6, 2002, that can be identified by a blue triangle etched on the blade airfoil suction surface close to the leading edge tip of each blade, no further action is required.

(b) On RB211-535E4 engines, operated to Flight Profile A, ultrasonically inspect, and if required, relubricate using the following Table 2:

Table 2.—RB211-535E4 Flight Profile A

Engine location	Initial inspection within (CSN)	Type action	In accordance with	Repeat inspection within (CSN)
(1) On-wing	17,350.	(i) Root Probe, inspect and relubricate, OR	RB.211-72-C879 Revision 3, 3.A.(1) through 3.A.(7), dated October 9, 2002	1,400.
		(ii) Wave Probe	RB.211-72-C879 Revision 3, 3.B.(1) through 3.B.(7), dated October 9, 2002	1,150.
(2) In Shop	17,350.	Root Probe, inspect and relubricate	RB.211-72-C879 Revision 3, 3.C.(1) through 3.C.(4), dated October 9, 2002	1,400.

(c) On RB211-535E4 engines, operated to Flight Profile B, ultrasonically inspect, and if required, relubricate using the following Table 3:

Table 3.—RB211-535E4 Flight Profile B

Engine location	Initial inspection ithin (CSN)	Type action	In accordance with	Repeat inspection within (CSN)
(1) On-wing	12,350.	(i) Root Probe, inspect and relubricate, OR	RB.211-72-C879 Revision 3, 3.A.(1) through 3.A.(7), dated October 9, 2002	850.
		(ii) Wave Probe	RB.211-72-C879 Revision 3, 3.B.(1) through 3.B.(7), dated October 9, 2002	700.
(2) In Shop	12,350.	Root Probe, inspect and relubricate	RB.211-72-C879 Revision 3, 3.C.(1) through 3.C.(4), dated October 9, 2002	850.

(d) On RB211-535E4 engines, operated to combined Flight Profile A and B, ultrasonically inspect, and if required, relubricate using the following Table 4:

Table 4.—RB211-535E4 Flight Profile A and B

Engine location	Initial inspection within (CSN)	Type action	In accordance with	Repeat inspection within (CSN)
(1) On-wing	65% hard life (To calculate, Compliance Section 1.C.(4))	(i) Root Probe, inspect and relubricate, OR	RB.211-72-C879 Revision 3, 3.A.(1) through see 3.A.(7), dated October 9, 2002	As current flight profile.
		(ii) Wave Probe.	RB.211-72-C879 Revision 3, 3.B.(1) through 3.B.(7), dated October 9, 2002	As current flight profile.
(2) In Shop	65% hard life (To calculate, Compliance Section 1.C.(4))	Root Probe, inspect and relubricate	RB.211-72-C879 Revision 3, 3.C.(1) through see 3.C.(4), dated October 9, 2002	As current flight profile.

Note 2:

Fan blades that have been operated within RB211-535E4 Flight Profile A and B will have final life as defined in the Time Limits Manual. See References Section 1.G.(3), of MSB RB.211-72-C879, Revision 3, dated October 9, 2002.

(e) On RB211-535E4-B engines, ultrasonically inspect, and if required, relubricate using the following Table 5:

Table 5.—RB211-535E4-B

Engine location	Initial inspection within (CSN)	Type action	In accordance with	Repeat within (CSN) inspection
(1) On-wing.	17,000	(i) Root Probe, inspect and relubricate OR	RB.211-72-C879 Revision 3, 3.A.(1) through 3.A.(7), dated October 9, 2002	1,200.
		(ii) Wave Probe.	RB.211-72-C879 Revision 3, 3.B.(1) through 3.B.(7), dated October 9, 2002	1,000.
(2) In Shop	17,000	Root Probe, inspect and relubricate	RB.211-72-C879 inspect and Revision 3, 3.C.(1) through 3.C.(4), dated October 9, 2002	1,200

Optional Terminating Action

(f) Application of Metco 58 blade root coating using RR SB RB.211-72-C946, Revision 1, dated August 6, 2002, constitutes terminating action to the repetitive inspection requirements specified in paragraphs (b), (c), (d), and (e) of this AD.

Alternative Methods of Compliance

(g) 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 request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO.

Note 3:

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

(h) Special flight permits may be issued in accordance with §§ 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 done.

Note 4:

The subject of this AD is addressed in CAA airworthiness directive AD 002-01-2000, dated October 9, 2002.

Issued in Burlington, Massachusetts, on February 10, 2003.

Peter A. White,

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