[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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