### 34560 Federal Register / Vol. 69, No. 119 / Tuesday, June 22, 2004 / Rules and Regulations 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. 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: 2004

– 12

– 19 Airbus: Amendment 39

– 13680. Docket 2003

–NM

– 63

–AD. Applicability: Model A319, A320, and A321 series airplanes, certificated in any category; except those airplanes on which Airbus Modification 30737 has been accomplished in production (reference Airbus Service Bulletin A320

– 24

– 1099, Revision 02, dated February 11, 2003, in service).

Compliance: Required as indicated, unless accomplished previously.

To prevent ignition of the input filter capacitors of the transformer rectifier unit (TRU) in position 2 of the avionics compartment, which could potentially result in smoke in the cockpit, accomplish the following: Replacement

(a) Prior to the accumulation of 15,000 total flight hours, or within 16 months after the effective date of this AD, whichever occurs later, replace the TRU, part number Y005

– 2, with a new TRU, part number Y005

– 3, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320

– 24

– 1099, Revision 02, dated February 11, 2003.

(b) Replacements accomplished before the effective date of this AD per Airbus Service Bulletin A320

– 24

– 1099, dated March 5, 2002; or Revision 01, dated July 26, 2002; are considered acceptable for compliance with the corresponding action specified in this AD. Parts Installation

(c) As of the effective date of this AD no person shall install a TRU, part number Y005

– 2, within position 2 of the avionics compartment on any airplane. Alternative Methods of Compliance

(d) In accordance with 14 CFR 39.19, the Manager, International Branch, ANM 116, Transport Airplane Directorate, FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD. Incorporation by Reference

(e) Unless otherwise specified in this AD, the actions shall be done in accordance with Airbus Service Bulletin A320

– 24

– 1099, Revision 02, dated February 11, 2003. 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 Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741

– 6030, or go to: http://www.archives.gov/federal

_register/ code

_ of

_ federal

_regulations/ ibr

_locations.html. Note 1: The subject of this AD is addressed in French airworthiness directive 2002

– 554(B), dated November 13, 2002. Effective Date

(f) This amendment becomes effective on July 27, 2004.

Issued in Renton, Washington, on June 9, 2004. Kalene C. Yanamura, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 04

– 13701 Filed 6

– 21

– 04; 8:45 am] **BILLING CODE 4910**
**– 13**  **– P** 
**DEPARTMENT OF TRANSPORTATION Federal Aviation Administration**  **14 CFR Part 39 [Docket No. 2001** 
**– NE** 
**– 50**  **– AD; Amendment**  **39 –**  **13681; AD 2004**
**– 13**  **– 01]**  **RIN 2120**
**– AA64**  **Airworthiness Directives; Dowty Aerospace Propellers Type R321/4** 
**– 82**  **– F/8, R324/4** 
**– 82**  **– F/9, R333/4** 
**– 82**  **– F/12,**  **and R334/4**
**– 82**  **– F/13 Propeller**  **Assemblies AGENCY**  **:** Federal Aviation Administration, DOT. **ACTION :**  Final rule. **SUMMARY :**  This amendment supersedes an existing airworthiness directive (AD) that applies to Dowty Aerospace Propellers (Dowty) Type R334/4

– 82

– F/ 13 propeller assemblies. That AD currently requires a one-time ultrasonic inspection of propeller hubs, part number (P/N) 660709201, for cracks. This amendment requires initial and repetitive ultrasonic inspections of propeller hubs, P/N 660709201, that are installed on airplanes, and for hubs and propellers in storage, initial ultrasonic inspection of propeller hubs before placing in service. Propeller hubs, P/N 660709201, are installed on Type R321/ 4

– 82

–F/8, R324/4

– 82

–F/9, R333/4

– 82

– F/12, and R334/4

– 82

–F/13 propeller assemblies. This amendment results from the manufacturer ’ s reevaluation of potential hub failure on Type R321/4

– 82

– F/8, R324/4

– 82

– F/9, R333/4

– 82

– F/ 12, and R334/4

– 82

–F/13 propeller assemblies. We are issuing this AD to prevent propeller hub failure due to cracks in the hub, which could result in loss of control of the airplane. **DATES :**  Effective July 27, 2004. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of July 27, 2004. **ADDRESSES :**  The service information referenced in this AD may be obtained from Dowty Aerospace Propellers, Anson Business Park, Cheltenham Road East, Gloucester GL 29QN, UK; telephone 44 (0) 1452 716000; fax 44 (0) 1452 716001. This information may be examined, by appointment, at the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202

– 741

– 6030, or go to: http://www.archives.gov/ federal

_register/ code

_ of

_ federal

_regulations/ ibr

_locations.html

. **FOR FURTHER INFORMATION CONTACT :**  Frank Walsh, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, telephone (781) 238

– 7158, fax (781) 238

– 7170. **SUPPLEMENTARY INFORMATION :**  A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 2002

– 01

– 28, Amendment 39

– 12623 (67 FR 4351, January 30, 2002), that applies to Dowty Type R334/4

– 82

–F/13 propeller assemblies was published in the Federal Register on April 28, 2003 (68 FR 22339). That action proposed to require initial and repetitive ultrasonic inspections of propeller hubs, P/N 660709201, that are installed on airplanes, and for hubs and propellers in storage, initial ultrasonic inspection of propeller hubs before placing in service. That action proposed to perform


### 34561 Federal Register / Vol. 69, No. 119 / Tuesday, June 22, 2004 / Rules and Regulations inspections in accordance with Dowty Mandatory Service Bulletin (MSB) No. 61

– 1119, Revision 3, dated March 8, 2002; MSB No. 61

– 1124, Revision 1, dated October 8, 2002; MSB No. 61

– 1125, Revision 1, dated October 9, 2002; and MSB No. 61

– 1126, Revision 1, dated October 9, 2002. The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK), classified these service bulletins as mandatory and issued CAA UK AD No. 003

– 11

– 2001, dated November 30, 2001; CAA UK AD No. 009

– 05

– 2002, dated April 15, 2003; CAA UK AD No. 010

– 05

– 2002, dated April 15, 2003; and CAA UK AD No. 011

– 05

– 2002, dated April 15, 2003 in order to ensure the airworthiness of these Dowty Propellers in the UK. Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. Request To Increase the Initial Inspection Interval

One commenter states that the initial inspection interval in the NPRM of 50 hours is unrealistically short to complete the inspection on a large, geographically wide-spread fleet. The commenter believes that the initial inspection interval should be increased to 200 hours.

We do not agree that we need to change the compliance time for the initial inspection. Dowty issued an MSB on May 7, 2002, and directed operators to conduct the initial inspection. Dowty also stated that the calendar compliance time for that inspection was within six months after the issue date of that MSB. Based on the issuance date of that MSB, all propellers should already be inspected. We have not changed the AD. Request To Increase the Repetitive Inspection Interval

One commenter requests that the repetitive inspection interval in the NPRM be increased from 1,000 hours to 2,000 hours based on the fact that only one crack was found in their fleet.

We do not agree. Dowty based the compliance time on an engineering evaluation of the 16 cracks found by this inspection. Five cracks were found on the same propeller model as flown by the commenter. We have not changed the AD. Credit for Previous Inspections on All Models

One commenter states that the previous inspections on the propeller should be applicable to all models, not just the R334/4

– 82

–F13 propeller.

We agree. We have changed the Applicability in the Regulatory text of the AD by adding Dowty Propeller Types R321/4

– 82

–F/8, R324/4

– 82

–F/9, and R333/4

– 82

–F/12. Request To Clarify the Economic Analysis Paragraph

One commenter states that the FAA underestimated the cost of the AD to U.S. operators. The commenter also provides additional information to better estimate the cost of the inspection.

We agree. Our revised estimate retains the 11 work hours per propeller and modifies the part cost from $1,650 per propeller to $300 per propeller. In addition, we increased the estimated number of airplanes from 10 airplanes to 50 airplanes and raised the labor rate to $65 per hour. Based on these revisions, the total cost for the inspection for U.S. operators will be about $126,875 for the fleet of affected airplanes. Clarification of CAA ADs Related to This AD

We inadvertently left out three CAA UK ADs in Note 3 of the NRPM supersedure. We have added the three CAA UK ADs in Note 3 of the AD.

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. Bilateral Agreement Information

These propeller models are manufactured in the 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. Economic Analysis

There are about 275 airplanes with propellers of the affected design in the worldwide fleet. The FAA estimates that there are about 125 Dowty Propellers Type R321/4

– 82

–F/8, R324/4

– 82

– F/9, R333/4

– 82

–F/12, and R334/4

– 82

– F/13 installed on airplanes of U.S. registry that would be affected by this AD. The FAA also estimates that it would take approximately 11 work hours per propeller to perform one inspection and replacement, and that the average labor rate is $65 per work hour. Required shipping and parts would cost approximately $300 per propeller. Based on these figures, the total cost of the AD to known U.S. operators is estimated to be $126,875. Regulatory Analysis

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.

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 the 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 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, 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: 49 U.S.C. 106(g), 40113, 44701. **§ 39.13 [Amended]**  ■ 2. Section 39.13 is amended by removing Amendment 39

– 12623 (67 FR


### 34562 Federal Register / Vol. 69, No. 119 / Tuesday, June 22, 2004 / Rules and Regulations 4351, January 30, 2002) and by adding a new airworthiness directive, Amendment 39

– 13681, to read as follows: 2004

– 13

– 01 Dowty Aerospace Propellers: Amendment 39

– 13681. Docket No. 2001

–NE

– 50

–AD. Supersedes AD 2002

– 01

– 28, Amendment 39

– 12623. Applicability

This airworthiness directive (AD) applies to Dowty Aerospace Propellers (Dowty) Type R321/4

– 82

– F/8, R324/4

– 82

– F/9, R333/4

– 82

– F/12, and R334/4

– 82

– F/13 propeller assemblies with propeller hubs part number (P/N) 660709201. These propeller assemblies are installed on, but not limited to, Construcciones Aeronauticas, S.A. (CASA) 212, British Aerospace Regional Aircraft Jetstream Models 3101 and 3201, Fairchild Aircraft, Inc., Merlin IIIC, and Merlin IVC/ Metro III airplanes.

Note 1: This AD applies to each propeller 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 propellers 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

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

To prevent propeller hub failure due to cracks in the hub, which could result in loss of control of the airplane, do the following: Initial Ultrasonic Inspection (a) Within 50 flight hours time-in-service (TIS) after the effective date of this AD, or within 60 days after the effective date of this AD, whichever occurs earlier, perform an initial ultrasonic inspection of the rear wall of the rear half of the propeller hub for cracks in accordance with Appendix A of the applicable Dowty Mandatory Service Bulletin (MSB) listed in the following Table 1: 

### T ABLE 

### 1.—A PPLICABLE 

### MSB FOR 

### P ROPELLER 

### T YPEPropeller assembly type Applicable MSB (1) R334/4–

82–F/13. MSB No. 61–1119, Revision 3, dated March 8, 2002. (2) R333/4–

82–F/12. MSB No. 61–1124, Revision 1, dated October 8, 2002. (3) R321/4–

82–F/8. MSB No. 61–1125, Revision 1, dated October 9, 2002. (4) R324/4–

82–F/9. MSB No. 61–1126, Revision 1, dated October 9, 2002 (b) For hubs and propellers in storage, perform an initial ultrasonic inspection of the rear wall of the rear half of the propeller hub for cracks, before placing in service, in accordance with Appendix A of the applicable Dowty MSB listed in Table 1 of this AD.

(c) Propeller hubs, P/N 660709201, used on Type R334/4

– 82

–F/13 propeller assemblies that have been previously inspected using a Dowty MSB listed in Table 1 or earlier issue of those MSBs, are considered to be in compliance with paragraph (a) of this AD. Repetitive Ultrasonic Inspections

(d) Thereafter, within 1,000 flight hours TIS after each ultrasonic inspection, perform an ultrasonic inspection of the rear wall of the rear half of the propeller hub for cracks in accordance with Appendix A of the applicable Dowty MSB listed in Table 1 of this AD. Inspection Reporting Requirements

(e) For each inspection, record the inspection data on a copy of Appendix B of the applicable MSB listed in Table 1 of this AD, and report the findings to the Manager, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803

– 5299 within 10 days after the inspection. Reporting requirements have been approved by the Office of Management and Budget (OMB) and assigned OMB control number 2120

– 0056. 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, Boston Aircraft Certification Office. Operators must submit their request through an appropriate FAA principal Maintenance Inspector, who may add comments and then send it to the Manager, Boston Aircraft 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 Boston Aircraft Certification Office. Special Flight Permits

(g) 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 airplane to a location where the requirements of this AD can be done. Documents That Have Been Incorporated by Reference

(h) The inspections must be done in accordance with the following Dowty Aerospace Propellers mandatory service bulletins: Document No. Pages Revision Date MSB No. 61–1119 ................................................................................................................ .................. 1 ............... 3 .............. Mar. 8, 2002. 2 ............... 2 ............... Dec. 6, 2001. Appendix A ..................................................................................................................... ........................ 1 .............. 1 ............... Nov. 27, 2001. 2 ............... Original .... Nov. 1, 2001. 3–6 ........... 1 ............... Nov. 27, 2001. Appendix B ..................................................................................................................... ........................ 1 .............. Original .... Nov. 1, 2001. Appendix C ..................................................................................................................... ........................ All ............ Original .... Nov. 27, 2001. Appendix D ..................................................................................................................... ........................ All ............ Original .... Dec. 6, 2001. Total pages: 29. MSB No. 61–1124 ................................................................................................................ .................. 1 ............... 1 .............. Oct. 8, 2002. 2–3 ........... Original .... May 7, 2002. Appendix A ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Appendix B ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Appendix C ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Appendix D ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Total pages: 30. MSB No. 61–1125 ................................................................................................................ .................. 1 ............... 1 .............. Oct. 9, 2002. 2–3 ........... Original .... May 7, 2002. Appendix A ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Appendix B ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Appendix C ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Appendix D ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Total pages: 30. MSB No. 61–1126 ................................................................................................................ .................. 1 ............... 1 .............. Oct. 9, 2002. 2–3 ........... Original .... May 7, 2002.


### 34563 Federal Register / Vol. 69, No. 119 / Tuesday, June 22, 2004 / Rules and Regulations
Document No. Pages Revision Date Appendix A ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Appendix B ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Appendix C ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Appendix D ..................................................................................................................... ........................ All ............ Original .... May 7, 2002. Total pages: 30.
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 Dowty Propellers, Anson Business Park, Cheltenham Road East, Gloucester GL 29QN, UK; telephone 44 (0) 1452 716000; fax 44 (0) 1452 716001. 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 National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202

– 741

– 6030, or go to: http://www.archives.gov/federal

_ register/code

_ of

_ federal

_regulations/ ibr

_locations.html

. Note 3: The subject of this AD is also addressed in CAA UK AD No. 003

– 11

– 2001, dated November 30, 2001; CAA UK AD No. 009

– 05

– 2002, dated April 15, 2003; CAA UK AD No. 010

– 05

– 2002, dated April 15, 2003; and CAA UK AD No. 011

– 05

– 2002, dated April 15, 2003. Effective Date

(i) This amendment becomes effective on July 27, 2004.

Issued in Burlington, Massachusetts, on June 10, 2004. Francis A. Favara, Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service. [FR Doc. 04

– 13773 Filed 6

– 21

– 04; 8:45 am] **BILLING CODE 4910**
**– 13**  **– P** 
**DEPARTMENT OF TRANSPORTATION Federal Aviation Administration**  **14 CFR Part 39 [Docket No. FAA** 
**– 2004** **– 18024; Directorate**  **Identifier 2003**
**– NE** 
**– 39**  **– AD; Amendment 39** 
**– 13684; AD 2004** 
**– 13**  **– 03]**  **RIN 2120**
**– AA64**  **Airworthiness Directives; Rolls-Royce (1971) Limited, Bristol Engine Division**  **Model Viper Mk.601**
**– 22 Turbojet**  **Engine AGENCY**  **:** Federal Aviation Administration (FAA), DOT. **ACTION :**  Final rule; request for comments. **SUMMARY :**  The FAA is adopting a newairworthiness directive (AD) for RollsRoyce (1971) Limited, Bristol Engine Division (RR) Model Viper Mk.601

– 22 turbojet engines. This AD requires reducing the life of certain 1st stage turbine rotor blades from 7,000 hours time-in-service (TIS) to 4,600 hours TIS, and provides a drawdown schedule for blades that have already exceeded the new reduced life limit. This AD results from the manufacturer ’ s investigations into failures of 1st stage turbine rotor blades. We are issuing this AD to prevent multiple failures of 1st stage turbine rotor blades that could result in a dual-engine shutdown. **DATES :**  Effective July 7, 2004.

We must receive any comments on this AD by August 23, 2004. **ADDRESSES :**  Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http:/ /dms.dot.gov and follow the instructions for sending your comments electronically.

• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.

• Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL

–401, Washington, DC 20590

– 001.

• Fax: (202) 493

– 2251. • Hand Delivery: Room PL

–401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

You can get the service information identified in this AD from Rolls-Royce Limited, Bristol Engines Division, Technical Publications Department CLS

–4, P.O. Box 3, Filton, Bristol, BS34 7QE England; telephone 117

– 979

– 1234, fax 117

– 979

– 7575.

You may examine the comments on this AD in the AD docket on the Internet at http://dms.dot.gov. **FOR FURTHER INFORMATION CONTACT :**  Ian Dargin, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803

– 5299; telephone (781) 238

– 7178; fax (781) 238

– 7199. **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 model Viper Mk.601

– 22 turbojet engines. The CAA advises that inspections of 1st stage turbine rotor blades, part numbers (P/Ns) V926000, V926293, and V926319, from engines that were returned from the field have identified cracks in the blade airfoil at an increasing rate. Under the current requirements to replace the blades at 7,000 hours TIS, the risk of dual-engine shutdowns is unacceptable. Reducing the class B life of these 1st stage turbine blades, recommended in Chapter 5 of the engine manual, from 7,000 hours TIS to a mandatory life limit of 4,600hours TIS reduces the risk of dualengine shutdowns. Relevant Service Information

We have reviewed and approved the technical contents of RR Alert Service Bulletin (ASB) 72

–A184, dated January 2001, that describes procedures for managing engine configurations to reduce the risk of dual-engine shutdowns. The CAA classified this service bulletin as mandatory and issued AD 004

– 01

– 2001 in order to ensure the airworthiness of these RR engines in the UK. Differences Between This AD and the Service Information

RR ASB 72

–A184, dated January 2001, specifies the date of receipt of the ASB as the baseline for the compliance time. This AD specifies the effective date of this AD as the baseline for the compliance time. 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. Under this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. We have 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.