AD 2001-23-13

[Federal Register Volume 67, Number 31 (Thursday, February 14, 2002)]
[Rules and Regulations]
[Pages 6864-6865]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 02-3588]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-350-AD; Amendment 39-12512; AD 2001-23-13]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; correction.

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SUMMARY: This document corrects information in an existing 
airworthiness directive (AD) that applies to certain Boeing Model 747 
series airplanes. That AD currently requires an inspection of the flap 
drive transmission of the trailing edge flaps at positions 2 and 7 to 
determine if a discrepant torque brake is installed; and corrective 
action, if necessary. That AD also imposes certain restrictions on the 
installation of affected spare parts. This document corrects and 
clarifies that the spares requirement in paragraph (b) of the final 
rule applies to only positions 2 and 7 of the trailing edge flaps, as 
identified in the Boeing service bulletin. This correction is necessary 
to ensure that operators are made aware that the spares requirement 
does not apply to positions 4 and 5 of the trailing edge flaps.

DATES: Effective December 31, 2001.
    The incorporation by reference of certain publications listed in 
the regulations was approved previously by the Director of the Federal 
Register as of December 31, 2001 (66 FR 58918, November 26, 2001).

FOR FURTHER INFORMATION CONTACT: Barbara Mudrovich, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 227-2983; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: On November 15, 2001, the Federal Aviation 
Administration (FAA) issued AD 2001-23-13, amendment 39-12512 (66 FR 
58918, November 26, 2001), which applies to certain Boeing Model 747 
series airplanes. That AD requires an inspection of the flap drive 
transmission of the trailing edge flaps at positions 2 and 7 to 
determine if a discrepant torque brake is installed; and corrective 
action, if necessary. That AD also imposes certain restrictions on the 
installation of affected spare parts. The actions required by that AD 
are intended to prevent damage to the flap system, adjacent systems, or 
structural components; or excessive skew of the trailing edge flap, 
which could result in flap asymmetry and consequent reduced 
controllability of the airplane.

Need for the Correction

    Information obtained recently by the FAA indicates that the spares 
requirement in paragraph (b) of the final rule needs to be clarified 
and corrected.
    As published, paragraph (b) of the final rule states that ``no 
person shall install on any airplane any transmission or torque brake 
assembly identified in the ``Existing Part Number'' column of Paragraph 
2.E. of Boeing Service Bulletin 747-27-2374, dated November 18, 1999.''
    Although paragraph (b) of the final rule did not limit the spares 
requirement to only positions 2 and 7 of the trailing edge flaps of the 
flap drive transmission, as indicated in the ``Summary'' of the final 
rule, and as clearly described in the ``Differences'' paragraph in the 
Notice of Proposed Rulemaking, it was the FAA's intent to do so.
    The FAA has determined that a correction to AD 2001-23-13 is 
necessary to correct and clarify the spares requirement. This 
correction will specify that the spares requirement in paragraph (b) of 
this AD is limited to the transmission or torque brake assembly of the 
trailing edge flaps at positions 2 and 7.

Correction of Publication

    This document corrects the error in AD 2001-23-13 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 31, 2001.
    Since this action only clarifies and corrects a current 
requirement, 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.

[[Page 6865]]

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):

2001-23-13  Boeing: Amendment 39-12512. Docket 2000-NM-350-AD.

    Applicability: Model 747 series airplanes, line numbers 0001 
through 1207, certificated in any category; excluding the airplanes 
having line number 1174 and Model 747SP series airplanes.

    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 (c) 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 damage to the flap system, adjacent systems, or 
structural components; or excessive skew of the trailing edge flap; 
which could result in flap asymmetry and consequent reduced 
controllability of the airplane, accomplish the following:

Part Verification/Replacement/Modification

    (a) Within 18 months or 7,500 flight hours after December 31, 
2001, whichever occurs later: Inspect the flap drive transmission of 
the trailing edge flaps at positions 2 and 7 to determine if a 
discrepant (``Belleville'' spring design) torque brake is installed 
in the transmission, by verifying the transmission part number, per 
Boeing Service Bulletin 747-27-2374, dated November 18, 1999. Then 
do the actions specified in paragraphs (a)(1) and (a)(2) of this AD, 
as applicable.
    (1) If the part number of the flap drive transmission shows that 
no discrepant torque brake is installed, no further action is 
required by this AD.
    (2) If the part number of the flap drive transmission shows that 
a discrepant torque brake may be installed, within the compliance 
time required by paragraph (a) of this AD: Inspect the part number 
of the torque brake to verify whether it is a discrepant torque 
brake, per the Accomplishment Instructions of the service bulletin.
    (i) If the part number of the torque brake shows that it is not 
a discrepant torque brake, no further action is required by this AD.
    (ii) If the part number of the torque brake shows that it is a 
discrepant torque brake: Within the compliance time required by 
paragraph (a) of this AD either replace the transmission with a new, 
improved transmission or rework the existing transmission by 
replacing the torque brake with a new or reworked torque brake 
having the part number specified in the service bulletin; per the 
Accomplishment Instructions of the service bulletin.

Spares

    (b) As of December 31, 2001, no person shall install on any 
airplane any transmission or torque brake assembly of the trailing 
edge flaps at positions 2 or 7, as identified in the ``Existing Part 
Number'' column of Paragraph 2.E. of Boeing Service Bulletin 747-27-
2374, dated November 18, 1999.

Alternative Methods of Compliance

    (c) 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. 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permit

    (d) 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

    (e) The actions shall be done in accordance with Boeing Service 
Bulletin 747-27-2374, dated November 18, 1999. This incorporation by 
reference was approved previously by the Director of the Federal 
Register as of December 31, 2001 (66 FR 58918, November 26, 2001). 
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

    (f) The effective date of this amendment remains December 31, 
2001.

    Issued in Renton, Washington, on February 7, 2002.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-3588 Filed 2-13-02; 8:45 am]
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