[Federal Register Volume 61, Number 50 (Wednesday, March 13, 1996)]
[Rules and Regulations]
[Pages 10270-10271]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-5856]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-276-AD; Amendment 39-9538; AD 96-03-01 R1]


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; correction.

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SUMMARY: This amendment clarifies information in an existing 
airworthiness directive (AD), applicable to certain Boeing Model 747 
series airplanes, that currently requires inspections of the lower 
engine mount to determine if the tangential link upper bolt and nut are 
oriented properly, and if the tangential link upper bolt nut is torqued 
within certain limits. Additionally, the AD requires replacement of the 
bolt and nut with serviceable parts, if necessary, and requires certain 
follow-on actions for airplanes on which the upper bolt is missing. The 
actions specified in the AD are intended to prevent separation of the 
engine from the airframe due to migration of the tangential link upper 
bolt. This amendment clarifies an incorrect description of a part that 
is to be inspected. This amendment is prompted by communications 
received from the manufacturer that this part was described incorrectly 
in the published version of the AD.

DATES: Effective February 16, 1996.
    The incorporation by reference of certain publications listed in 
the regulations was approved previously by the Director of the Federal 
Register as of February 16, 1996 (61 FR 3550, February 1, 1996).

FOR FURTHER INFORMATION CONTACT: Tammy L. Dow, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2771; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: On January 22, 1996, the FAA issued AD 96-
03-01, amendment 39-9496 (61 FR 3550, February 1, 1996), which is 
applicable to certain Boeing Model 747 series airplanes. That AD 
requires inspections of the lower engine mount to determine if the 
tangential link upper bolt and nut are oriented properly, and if the 
tangential link upper bolt nut is torqued within certain limits. 
Additionally, that AD requires replacement of the bolt and nut with 
serviceable parts, if necessary, and requires certain follow-on actions 
for airplanes on which the upper bolt is missing. Terminating action 
also is provided by that AD. That action was prompted by reports of 
migration of bolts completely from the tangential link of the aft 
engine mount, a condition which would reduce the capability of the 
retention system for the engine. The actions required by that AD are 
intended to prevent separation of the engine from the airplane due to 
migration of the tangential link upper bolt.
    Since the issuance of that AD, the manufacturer advised the FAA 
that, as published, paragraph (a)(1)(ii) of that AD incorrectly 
described a part. That paragraph specified that if the ``tangential 
link upper bolt'' is not installed on the forward side of the engine 
mount fitting, certain corrective actions are required. However, that 
paragraph should have specified that the corrective actions are 
necessary if the ``tangential link upper bolt nut'' is not installed on 
the forward side of the engine mount fitting. In all other parts of the 
published AD and its preamble, references to this part were described 
correctly.
    Action is taken herein to clarify these requirements of AD 96-03-01 
and to correctly add the AD as an amendment to section 39.13 of the 
Federal Aviation Regulations (14 CFR 39.13).
    The final rule is being reprinted in its entirety for the 
convenience of affected operators. The effective date remains February 
16, 1996.
    Since this action only clarifies a current requirement, it has no 
adverse economic impact and imposes no additional burden on any person. 
Therefore, notice and public procedures hereon 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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-9496 (61 FR 
3550, February 1, 1996), and by adding a new airworthiness directive 
(AD), amendment 39-9538, to read as follows:

96-03-01 R1 Boeing: Amendment 39-9538. Docket 95-NM-276-AD. Revises 
AD 96-03-01, Amendment 39-9496.

    Applicability: Model 747 series airplanes, as listed in Boeing 
Alert Service Bulletin 747-71A2277, dated November 29, 1995; 
certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 use the authority 
provided in paragraph (c) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent separation of the engine from the airplane, 
accomplish the following:
    (a) Within 90 days after the effective date of this AD, 
accomplish the requirements of paragraphs (a)(1) and (a)(2) of this 
AD in accordance with Boeing Alert Service Bulletin 747-71A2277, 
dated November 29, 1995.
    (1) Perform a visual inspection to ensure that installation of 
the tangential link upper bolt nut is on the forward side of the 
engine mount fitting.
    (i) If the tangential link upper bolt nut is installed on the 
forward side of the engine mount fitting, repeat the visual 
inspection at intervals not to exceed 18 months.
    (ii) If the tangential link upper bolt nut is not installed on 
the forward side of the engine mount fitting, prior to further 
flight, remove the nut, bolt, and washers and reinstall the nut, 
bolt, and washers in accordance with the alert service bulletin. 
Thereafter, repeat the visual inspection at intervals not to exceed 
18 months.
    (iii) If the tangential link upper bolt is missing from the 
engine mount fitting, prior to further flight, perform the various 
follow-on actions in accordance with the alert service bulletin. 
(The follow-on actions include visual inspections, magnetic particle

[[Page 10271]]
inspections, replacement of the lower engine mount fitting with a 
serviceable part, if necessary; installation of new safety links, 
bolts, and nuts; and installation of a new tangential link upper 
bolt.) Thereafter, repeat the visual inspection at intervals not to 
exceed 18 months.
    (2) Perform an inspection to verify that the torque value of the 
tangential link upper bolt (on both sides of the mount) is within 
the limits specified in the alert service bulletin.
    (i) If the torque value of the tangential link upper bolt nut is 
within the limits specified in the alert service bulletin, repeat 
the inspection (verification) at intervals not to exceed 18 months.
    (ii) If the torque value of the tangential link upper bolt nut 
is outside the limits specified in the alert service bulletin, prior 
to further flight, perform a visual inspection of the tangential 
link upper bolt and washer for any damage or discrepancy, in 
accordance with the alert service bulletin.
    (A) If no damage or discrepancy of the tangential link upper 
bolt and washers is found, prior to further flight, replace the bolt 
nut with a new or serviceable part in accordance with the alert 
service bulletin. Thereafter, repeat the inspection (verification) 
specified in paragraph (a)(2) of this AD at intervals not to exceed 
18 months.
    (B) If any damage or discrepancy of the tangential link upper 
bolt and washers is found, prior to further flight, replace the 
damaged or discrepant part with a new or serviceable part, and 
replace the bolt nut with a new or serviceable part, in accordance 
with the alert service bulletin. Thereafter, repeat the inspection 
(verification) specified in paragraph (a)(2) of this AD at intervals 
not to exceed 18 months.
    (b) Replacement of the safety links with modified safety links 
in accordance with Boeing Service Bulletin 747-71-2206, dated April 
16, 1987; or Boeing Service Bulletin 747-71-2206, Revision 1, dated 
November 12, 1987, as revised by Boeing Notice of Status Change No. 
747-71-2206 NSC 1, dated December 4, 1987, and Boeing Notice of 
Status Change No. 747-71-2206 NSC 2, dated March 17, 1988; 
constitutes terminating action for the repetitive inspection 
requirements of this AD.
    (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, 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (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.
    (e) The inspections, replacement, and follow-on actions shall be 
done in accordance with Boeing Alert Service Bulletin 747-71A2277, 
dated November 29, 1995. 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, as of February 16, 1996 (61 FR 
3550, February 1, 1996). 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.
    (f) This amendment is effective on February 16, 1996.

    Issued in Renton, Washington, on March 6, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-5856 Filed 3-12-96; 8:45 am]
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