[Federal Register Volume 64, Number 120 (Wednesday, June 23, 1999)]
[Proposed Rules]
[Pages 33437-33439]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-15931]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NM-72-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 767 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the supersedure of an existing
airworthiness directive (AD), applicable to certain Boeing Model 767
series airplanes, that currently requires repetitive inspections to
detect cracking or damage of the forward and aft lugs of the diagonal
brace of the nacelle strut, and follow-on actions, if necessary. That
AD also provides optional terminating action for the repetitive
inspections. This proposal would require accomplishment of the
previously optional terminating action. This proposal is prompted by a
report that a fractured diagonal brace lug was found during a routine
maintenance inspection. The actions specified by the proposed AD are
intended to prevent cracking of the diagonal brace of the nacelle
strut, which could result in failure of the diagonal brace, and
consequent fatigue failure of a strut secondary load path and
separation of the engine and strut.
DATES: Comments must be received by August 9, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 99-NM-72-AD, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056. Comments may be inspected at this location
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal
holidays.
The service information referenced in the proposed rule 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.
FOR FURTHER INFORMATION CONTACT: James G. Rehrl, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-2783; fax (425) 227-1181.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed 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 above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this notice may be changed in
light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 99-NM-72-AD.'' The
[[Page 33438]]
postcard will be date stamped and returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules
Docket No. 99-NM-72-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On March 17, 1999, the FAA issued AD 99-07-06, amendment 39-11091
(64 FR 14578, March 26, 1999), applicable to certain Boeing Model 767
series airplanes, to require repetitive inspections to detect cracking
or damage of the forward and aft lugs of the diagonal brace of the
nacelle strut, and follow-on actions, if necessary. That action also
provides optional terminating action for the repetitive inspections.
That action was prompted by a report that a fractured diagonal brace
lug was found during a routine maintenance inspection. The requirements
of that AD are intended to detect and correct cracking of the diagonal
brace of the nacelle strut, which could result in failure of the
diagonal brace, and consequent fatigue failure of a strut secondary
load path and separation of the engine and strut.
Actions Since Issuance of Previous Rule
In the preamble to AD 99-07-06, the FAA specified that the actions
required by that AD were considered ``interim action'' and that further
rulemaking action was being considered. The FAA has determined that
further rulemaking action is indeed necessary; this proposed AD follows
from that determination and would require accomplishment of the
previously optional terminating action, in accordance with Boeing Alert
Service Bulletin 767-54A0094, dated May 22, 1998. (That service
bulletin was referenced in AD 99-07-06 as the appropriate source of
service information for accomplishment of the replacement.)
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other products of this same type design, the
proposed AD would supersede AD 99-07-06 to continue to require
repetitive inspections to detect cracking or damage of the forward and
aft lugs of the diagonal brace of the nacelle strut, and follow-on
actions, if necessary. In addition, this proposed AD would require
accomplishment of the previously optional terminating action for the
repetitive inspection requirements.
Cost Impact
There are approximately 208 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 105 airplanes of U.S. registry
would be affected by this proposed AD.
The inspections that are currently required by AD 99-07-06, and
retained in this proposed AD, take approximately 1 work hour per
airplane to accomplish, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of the currently required
inspections on U.S. operators is estimated to be $6,300, or $60 per
airplane, per inspection cycle.
The replacement that is proposed in this AD action would take
approximately 8 work hours (4 work hours for each strut) per airplane
to accomplish, at an average labor rate of $60 per work hour. Required
parts would cost approximately $50,000 per airplane.
Based on these figures, the cost impact of the proposed replacement
required by this AD on U.S. operators is estimated to be $5,300,400, or
$50,480 per airplane.
The cost impact figures discussed above are based on assumptions
that no operator has yet accomplished any of the current or proposed
requirements of this AD action, and that no operator would accomplish
those actions in the future if this AD were not adopted.
Regulatory Impact
The regulations proposed herein would not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, will not have a significant economic impact,
positive or negative, on a substantial number of small entities under
the criteria of the Regulatory Flexibility Act. A copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting the Rules
Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
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 [Amended]
2. Section 39.13 is amended by removing amendment 39-11091 (64 FR
14578, March 26, 1999), and by adding a new airworthiness directive
(AD), to read as follows:
Boeing: Docket 99-NM-72-AD. Supersedes AD 99-07-06, amendment 39-
11091.
Applicability: Model 767 series airplanes; as listed in Boeing
Alert Service Bulletin 767-54A0094, dated May 22, 1998; 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 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 prevent cracking of the diagonal brace of the nacelle strut,
which could result in failure of the diagonal brace, and consequent
fatigue failure of a strut secondary load path and separation of the
engine and strut, accomplish the following:
Restatement of Requirements of AD 99-07-06
Initial Inspection
(a) Perform a detailed visual inspection to detect cracking or
damage of the forward and aft lugs of the diagonal brace of the
nacelle strut, on the left and right sides of the airplane, in
accordance with Boeing Alert Service Bulletin 767-54A0094, dated May
22, 1998. Perform the inspection at the time specified in paragraph
(a)(1) or (a)(2) of this AD, as applicable.
[[Page 33439]]
(1) For airplanes in Groups 1, 3, and 4: Inspect prior to the
accumulation of 12,000 total flight cycles, or within 90 days after
April 12, 1999 (the effective date of AD 99-07-06, amendment 39-
11091), whichever occurs later.
(2) For airplanes in Group 2: Inspect prior to the accumulation
of 24,000 total flight cycles, or within 90 days after April 12,
1999, whichever occurs later.
Follow-On Actions
(b) If no cracking or damage is detected during the inspection
required by paragraph (a) of this AD, repeat the inspection
thereafter at the interval specified in paragraph (b)(1) or (b)(2)
of this AD, as applicable, in accordance with Boeing Alert Service
Bulletin 767-54A0094, dated May 22, 1998. Repeat the inspection
until the actions specified by paragraph (d) or (e) of this AD have
been accomplished.
(1) For airplanes in Groups 1, 3, and 4; and for airplanes in
Group 2 on which the diagonal brace has accumulated more than 32,000
total flight cycles: Repeat the inspection at intervals not to
exceed 1,000 flight cycles.
(2) For airplanes in Group 2 on which the diagonal brace has
accumulated 32,000 or fewer total flight cycles: Repeat the
inspection at intervals not to exceed 3,000 flight cycles.
(c) If any cracking or damage is detected during any inspection
required by paragraph (a) or (b) of this AD, prior to further
flight, remove the diagonal brace and perform additional inspections
to detect damage of the strut secondary load paths, in accordance
with Part 4 of Boeing Alert Service Bulletin 767-54A0094, dated May
22, 1998; and accomplish the requirements of paragraphs (c)(1) and,
if applicable, (c)(2) of this AD.
(1) Prior to further flight, replace the one-piece diagonal
brace with a new three-piece diagonal brace, in accordance with Part
3 of the Accomplishment Instructions of the alert service bulletin.
Such replacement constitutes terminating action for the requirements
of this AD.
(2) If any additional damage of the alternate load paths is
detected, prior to further flight, repair in accordance with a
method approved by the Manager, Seattle Aircraft Certification
Office (ACO), FAA, Transport Airplane Directorate; or in accordance
with data meeting the type certification basis of the airplane
approved by a Boeing Company Designated Engineering Representative
who has been authorized by the Manager, Seattle ACO, to make such
findings.
(d) For airplanes on which no cracking is detected during the
inspection required by paragraph (a) of this AD, in lieu of
accomplishing repetitive inspections in accordance with paragraph
(b) of this AD, rework of the forward and aft lugs of the diagonal
brace may be accomplished in accordance with Part 2 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 767-
54A0094, dated May 22, 1998. If such rework is accomplished: Within
12,000 flight cycles after the rework, repeat the inspection
required by paragraph (a) of this AD; and, prior to the accumulation
of 37,500 total flight cycles on the diagonal brace, replace the
one-piece diagonal brace with a new three-piece diagonal brace, in
accordance with Part 3 of the Accomplishment Instructions of the
alert service bulletin. Such replacement constitutes terminating
action for the requirements of this AD.
New Requirements of This AD
Terminating Action
(e) Prior to the accumulation of 37,500 total flight cycles, or
within 180 days after the effective date of this AD, whichever
occurs later: Replace the one-piece diagonal brace with a new three-
piece diagonal brace, in accordance with Part 3 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 767-
54A0094, dated May 22, 1998. Such replacement constitutes
terminating action for the requirements of this AD.
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 ACO. 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.
Issued in Renton, Washington, on June 17, 1999.
Dorenda D. Baker,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-15931 Filed 6-22-99; 8:45 am]
BILLING CODE 4910-13-U
