[Federal Register Volume 64, Number 245 (Wednesday, December 22, 1999)]
[Rules and Regulations]
[Pages 71635-71637]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-33167]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-323-AD; Amendment 39-11456; AD 99-25-13 C1]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777-200 and -300 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; correction.

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SUMMARY: This document corrects two typographical errors that appeared 
in airworthiness directive (AD) 99-25-13 that applies to all Boeing 
Model 777-200 and -300 series airplanes. That AD currently requires 
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. This document corrects incorrect 
paragraph references. This correction is necessary to ensure that 
operators accomplish the appropriate requirements of the AD.

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

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: Airworthiness Directive (AD) 99-25-13, 
amendment 39-11456, applicable to all Boeing Model 777-200 and -300 
series airplanes, was published in the Federal Register on December 8, 
1999 (64 FR 68618). That AD requires revising the Limitations Section 
of the Airplane Flight Manual to prohibit the dispatch

[[Page 71636]]

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. That AD was prompted by reports of inflight shutdowns due to 
sheared backup generator shafts. The actions specified by that 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.

Need for the Correction

    Information obtained recently by the FAA indicates that paragraph 
(e) of AD 99-25-13 contains two typographical errors. That paragraph 
specifies ``paragraphs (c)(1) and (c)(2)'' as the appropriate paragraph 
references for the action required after replacement of the backup 
generators.
    The FAA has determined that a correction to AD 99-25-13 is 
necessary. The correction to paragraph (e) of that AD will specify 
``paragraphs (e)(1) and (e)(2)'' as the appropriate paragraph 
references.

Correction of Publication

    This document corrects the errors and correctly adds the AD as an 
amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 
39.13).
    The AD is reprinted in its entirety for the convenience of affected 
operators. The effective date of the AD remains December 23, 1999.
    Since this action only corrects typographical errors, it has no 
adverse economic impact and imposes no additional burden on any person. 
Therefore, the FAA has determined that notice and public procedures are 
unnecessary.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Correction

    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.


Sec. 39.13  [Corrected]

    2. Section 39.13 is amended by correctly adding the following 
airworthiness directive (AD):

99-25-13 C1 Boeing: Amendment 39-11456. Docket 99-NM-323-AD.

    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 (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 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:

Revisions to the Airplane Flight Manual

    (a) For all airplanes: Within 14 days after the effective date 
of this AD, 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.''

Prohibited Servicing or Replacement

    (b) For all airplanes: As of 14 days after the effective date of 
this AD, 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 the effective date of this 
AD, 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

    (d) Within 14 days after the effective date of this AD, and 
thereafter prior to each flight: Accomplish paragraph (d)(1), 
(d)(2), or (d)(3) of this AD, as applicable.

Rolls-Royce Engines

    (1) For airplanes equipped with Rolls-Royce Trent 800 series 
turbofan engines, accomplish paragraphs (d)(1)(i) and (d)(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 Maintenance Access Terminal 
(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) or 2.a.(2), as 
applicable, in accordance with that service letter.

General Electric Engines

    (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) or 1.a.(2), as applicable, in accordance 
with the service letter.

Pratt & Whitney Engines

    (3) For Model 777 series airplanes equipped with Pratt & Whitney 
PW4000 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-
24-025, dated August 18, 1999, in accordance with that service 
letter.
    (i) 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.
    (ii) If the backup generator shaft is found to be sheared, or 
either of the low oil

[[Page 71637]]

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

    (e) For all airplanes: 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 (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 paragraph (d)(1), (d)(2), or 
(d)(3) of this AD, as applicable.

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, 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

    (g) 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 airplane to a location where 
the requirements of this AD can be accomplished.

Incorporation by Reference

    (h) Except as provided by paragraphs (a) and (d)(3)(i) 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.
    (i) The effective date of this amendment remains December 23, 
1999.

    Issued in Renton, Washington, on December 16, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-33167 Filed 12-21-99; 8:45 am]
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