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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2000-NM-108-AD; Amendment 39-11803; AD 2000-13-04] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Final rule; request for comments. 

# SUMMARY:

This amendment supersedes an existing airworthiness directive (AD), applicable to all Boeing Model 777-200 and -300 series airplanes, that currently requires revising the Limitations Section of the Airplane Flight Manual (AFM) to prohibit the dispatch of certain airplanes under certain conditions. That amendment also requires repetitive inspections to ensure correct operation of the backup generators; and, for certain airplanes, a one-time inspection to detect damage of the engine external gearbox; and corrective actions, if necessary. This amendment continues the AFM and inspection requirements and expands certain corrective action requirements. This amendment is prompted by reports of inflight shutdowns due to sheared backup generator shafts. The actions specified in this AD are intended to prohibit the dispatch of an airplane with an engine-mounted backup generator having a sheared shaft; and to detect and correct damage to the engine, which could result in inflight shutdowns. 

# DATES:

Effective July 13, 2000. 

The incorporation by reference of certain publications, as listed in the regulations, was approved previously by the Director of the Federal Register as of December 23, 1999 (64 FR 68618, December 8, 1999). 

Comments for inclusion in the Rules Docket must be received on or before August 28, 2000. 

# ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-108-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may also be sent via the Internet using the following address: 9-anm-iarcomment@faa.gov. Comments sent via the Internet must contain “Docket No. 2000-NM-108-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text. 

The service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. 

# FOR FURTHER INFORMATION CONTACT:

Ed Hormel, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2681; fax (425) 227-1181. 

# SUPPLEMENTARY INFORMATION:

On November 30, 1999, the FAA issued AD 99-25-13, amendment 39-11456 (64 FR 68618, December 8, 1999), applicable to all Boeing Model 777-200 and -300 series airplanes, to require revising the Limitations Section of the Airplane Flight Manual to prohibit the dispatch of certain airplanes under certain conditions. That AD also requires repetitive inspections to ensure correct operation of the backup generators; and, for certain airplanes, a one-time inspection to detect damage of the engine external gearbox; and corrective actions, if necessary.   

                    A correction of the final rule was published in the                     **Federal Register**                     on December 22, 1999 (64 FR 71635, December 23, 1999). That AD (AD 99-25-13 C1, amendment 39-11456) corrects incorrect paragraph references in AD 99-25-13. That action was prompted by reports of inflight shutdowns due to sheared backup generator shafts. The actions required by the correction AD are intended to prohibit the dispatch of an airplane with an engine-mounted backup generator having a sheared shaft; and to detect and correct damage to the engine, which could result in inflight shutdowns.                 

## Actions Since Issuance of Previous Rule 

Since the issuance of AD 99-25-13 C1, the FAA has received questions from an operator regarding the following corrective action procedures: 
    - Boeing Service Letter 777-SL-24-023-B, dated August 16, 1999, specifies accomplishment of the applicable actions specified in both Steps 2.a.(1) and 2.a.(2) of that service letter. However, paragraph (d)(1)(ii) in that AD requires the accomplishment of either Steps 2.a.(1) or 2.a.(2), as applicable.
    - Boeing Service Letter 777-SL-24-024, dated August 16, 1999, specifies accomplishment of the applicable actions specified in both Steps 1.a.(1) and 1.a.(2) of that service letter. However, paragraph (d)(2) in that AD requires the accomplishment of either Steps 1.a.(1) or 1.a.(2), as applicable.

In response to the operator's questions, the FAA has determined that it is necessary to require the accomplishment of both of the applicable corrective actions specified in paragraph (d)(1)(ii) in that AD [cited as paragraph (f)(1)(ii) in this AD] for airplanes equipped with certain Rolls-Royce engines, and both of the applicable corrective actions specified in paragraph (d)(2) in that AD [cited as paragraph (f)(2) of this AD] for airplanes equipped with certain General Electric engines. 

                    In addition, paragraphs (d)(1)(ii) and (d)(2) in that AD should have specified that the corrective actions required by those paragraphs are specified in certain                           ( print page 39789)                        steps “of the service letter.” That service letter clarification has been added to paragraphs (f)(1)(ii) and (f)(2) of this AD, accordingly.                 

Paragraphs (d)(3), (d)(3)(i), and (d)(3)(ii) in that AD are cited as paragraphs (d), (d)(1), and (d)(2) of this AD for airplanes equipped with certain Pratt & Whitney engines. Other paragraphs of this AD also have been reformatted. 

## Explanation of Requirements of Rule 

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of this same type design, this AD supersedes AD 99-25-13 C1 to continue to require revising the Limitations Section of the Airplane Flight Manual to prohibit the dispatch of certain airplanes under certain conditions; repetitive inspections to ensure correct operation of the backup generators; and, for certain airplanes, a one-time inspection to detect damage of the engine external gearbox; and corrective actions, if necessary. This amendment also expands the requirements for certain corrective actions. 

## Determination of Rule's Effective Date 

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 shall 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.                 

Submit comments using the following format: 
    - Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
    - For each issue, state what specific change to the AD is being requested.
    - Include justification ( e.g.,                      reasons or data) for each request.                 

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 rule must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-108-AD.” The postcard will be date stamped and returned to the commenter. 

## Regulatory Impact 

The regulations adopted herein will 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. 

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it 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:49 U.S.C. 106(g), 40113, 44701. 

§ 39.13 

2. Section 39.13 is amended by removing amendment 39-11456 ( 64 FR 71635, December 23, 1999), and by adding a new airworthiness directive (AD), amendment 39-11803, to read as follows: 

**2000-13-04 Boeing:**                             Amendment 39-11803. Docket 2000-NM-108-AD. Supersedes AD 99-25-13 C1, Amendment 39-11456.                        

*Applicability:*                             Model 777-200 and -300 series airplanes equipped with Rolls-Royce Trent 800, General Electric GE90, or Pratt & Whitney PW4000 series turbofan engines; certificated in any category.                         

# Note 1: 

This AD applies to each airplane 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 airplanes 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 (h) 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 prohibit dispatch of an airplane with an engine-mounted backup generator having a sheared shaft; and to detect and correct damage to the engine, which could result in inflight shutdowns; accomplish the following: 

## Restatement of Requirements of AD 99-25-13 C1 

### Revisions to the Airplane Flight Manual 

(a) For all airplanes: Within 14 days after December 23, 1999 (the effective date of AD 99-25-13 C1, amendment 39-11456), revise the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to include the following information. This may be accomplished by inserting a copy of this AD in the AFM. 

Dispatch of the airplane with an engine-mounted backup generator having a sheared shaft is prohibited. 

                            Following replacement of the backup generator on both the left and right engines, extended twin-engine operations (ETOPS) flight is prohibited until a non-ETOPS flight of at least one hour in duration is accomplished.                                  ( print page 39790)    

### Prohibited Servicing or Replacement 

(b) For all airplanes: As of 14 days after December 23, 1999, the servicing of both the left and right backup generators or replacement of both backup generators with new or serviceable components by the same individual prior to the same flight is prohibited. 

### One-Time Actions for Rolls-Royce Engines 

(c) For airplanes equipped with Rolls-Royce Trent 800 series turbofan engines: Within 14 days after December 23, 1999, determine whether the status message “ELEC BACKUP GEN L(R)” and the maintenance message “Backup generator L(R) has a sheared shaft” have occurred within the last 250 flight hours prior to the effective date of this AD. If these messages have occurred during that time, accomplish follow-on corrective actions, as applicable, at the times specified in paragraphs C.1.(c) and D. of Rolls-Royce Service Bulletin RB.211-72-C813, Revision 1, dated July 16, 1999, in accordance with the procedures specified in the service bulletin. 

# Note 2:

Boeing Service Letter 777-SL-24-023-B, dated August 16, 1999, references Rolls-Royce Service Bulletin RB.211-72-C813, Revision 1, dated July 16, 1999, as an additional source of service information to accomplish certain actions required by this AD. 

*Inspections and Corrective Actions:*                             Pratt & Whitney Engines                         

(d) For Model 777 series airplanes equipped with Pratt & Whitney PW4000 series turbofan engines: Within 14 days after December 23, 1999, and thereafter prior to each flight, if the status message “ELEC BACKUP GEN L(R)” is active, prior to further flight, inspect the Maintenance Access Terminal (MAT) for certain maintenance messages indicating a sheared shaft or low oil pressure, in accordance with Step 1.a. of Boeing Service Letter 777-SL-24-025, dated August 18, 1999. 

(1) If any of the specified maintenance messages is active, prior to further flight, remove and replace the backup generator in accordance with Airplane Maintenance Manual (AMM) 24-25-01-000-801 or 24-25-01-400-801, as applicable. 

(2) If the backup generator shaft is found to be sheared, or either of the low oil pressure messages are active, prior to further flight, accomplish the corrective actions specified in Step 1.a.(1) of Boeing Service Letter 777-SL-24-025, dated August 18, 1999, in accordance with that service letter. 

### *Flight Test After Replacement of Backup Generators:*                             Pratt & Whitney Engines                         

(e) For airplanes equipped with Pratt & Whitney PW4000 series turbofan engines: As of 14 days after December 23, 1999, following any replacement of the backup generator on both the left and right engines, accomplish paragraphs (e)(1) and (e)(2) of this AD at the times specified in those paragraphs. 

(1) Prior to any ETOPS flight, conduct a non-revenue test flight of at least one hour in duration, or a non-ETOPS flight that is either a non-revenue or revenue flight of at least one hour in duration. 

(2) Prior to further flight after accomplishment of the action required by paragraph (e)(1) of this AD: Verify accomplishment of the maintenance actions required by paragraphs (d), (d)(1), and (d)(2) of this AD, as applicable. 

## New Requirements of This AD 

### Inspections and Corrective Actions: Rolls-Royce and General Electric Engines 

(f) Within 14 days after the effective date of this AD, and thereafter prior to each flight: Accomplish paragraphs (f)(1) or (f)(2) of this AD, as applicable. 

(1) For airplanes equipped with Rolls-Royce Trent 800 series turbofan engines: Accomplish paragraphs (f)(1)(i) and (f)(1)(ii) of this AD. 

(i) Inspect the Electrical Maintenance Page of the engine indicating and crew alerting system (EICAS), and perform follow-on corrective actions, as applicable, at the times specified in and in accordance with the procedures specified in Boeing Service Letter 777-SL-24-023-B, dated August 16, 1999. 

(ii) If the status message “ELEC BACKUP GEN L(R)” is active: Prior to further flight, inspect the MAT for certain maintenance messages indicating a sheared shaft or low oil pressure, as specified in Step 2.a. of Boeing Service Letter 777-SL-24-023-B, dated August 16, 1999; and accomplish the corrective actions specified in Steps 2.a.(1) and 2.a.(2) of the service letter, as applicable, in accordance with that service letter. 

(2) For airplanes equipped with General Electric GE90 series turbofan engines: If the status message “ELEC BACKUP GEN L(R)” is active, prior to further flight, inspect the MAT for certain maintenance messages indicating a sheared shaft or low oil pressure, as specified in Step 1.a. of Boeing Service Letter 777-SL-24-024, dated August 16, 1999; and accomplish the corrective actions specified in Steps 1.a.(1) and 1.a.(2) of the service letter, as applicable, in accordance with the service letter. 

### Flight Test After Replacement of Backup Generators: Rolls-Royce and General Electric Engines 

(g) For airplanes equipped with Rolls-Royce Trent 800 and General Electric GE90 series turbofan engines: As of 14 days after the effective date of this AD, following any replacement of the backup generator on both the left and right engines, accomplish paragraphs (g)(1) and (g)(2) of this AD at the times specified in those paragraphs. 

(1) Prior to any ETOPS flight, conduct a non-revenue test flight of at least one hour in duration, or a non-ETOPS flight that is either a non-revenue or revenue flight of at least one hour in duration. 

(2) Prior to further flight after accomplishment of the action required by paragraph (g)(1) of this AD: Verify accomplishment of the maintenance actions required by paragraph (f)(1) or (f)(2) of this AD, as applicable. 

### Alternative Methods of Compliance 

(h) 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, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. 

# Note 3:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

### Special Flight Permits 

(i) 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 accomplished. 

### Incorporation by Reference 

(j) Except as provided by paragraphs (a), (d)(1), (e)(1), (e)(2), (g)(1), and (g)(2) of this AD, the actions shall be done in accordance with Rolls-Royce Service Bulletin RB.211-72-C813, Revision 1, dated July 16, 1999; Boeing Service Letter 777-SL-24-023-B, dated August 16, 1999; Boeing Service Letter 777-SL-24-024, dated August 16, 1999; or Boeing Service Letter 777-SL-24-025, dated August 18, 1999; as applicable. This incorporation by reference was approved previously by the Director of the Federal Register as of December 23, 1999 (64 FR 68618, December 8, 1999). Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. 

### Effective Date 

(k) This amendment becomes effective on July 13, 2000. 

Issued in Renton, Washington, on June 21, 2000. 

Donald L. Riggin, 

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 00-16233 Filed 6-27-00; 8:45 am] 

BILLING CODE 4910-13-P