[Federal Register Volume 63, Number 173 (Tuesday, September 8, 1998)]
[Rules and Regulations]
[Pages 47423-47425]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-23738]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-18-AD; Amendment 39-10742; AD 98-18-26]
RIN 2120-AA64
Airworthiness Directives; Airbus Model A320 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Airbus Model A320 series airplanes, that requires
repetitive inspections to detect fatigue cracking of the front spar
vertical stringers on the wings; and repair, if necessary. This
amendment also provides for an optional terminating action for the
repetitive inspections. This amendment is prompted by issuance of
mandatory continuing airworthiness information by a foreign civil
airworthiness authority. The actions specified by this AD are intended
to detect and correct fatigue cracking of the front spar vertical
stringers on the wings, which could result in reduced structural
integrity of the airframe.
DATES: Effective October 13, 1998.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of October 13, 1998.
ADDRESSES: The service information referenced in this AD may be
obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707
Blagnac Cedex, France. This information may be examined at the Federal
Aviation Administration (FAA), Transport Airplane Directorate, Rules
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager,
International Branch, ANM-116, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)
227-2110; fax (425) 227-1149.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to certain Airbus A320 series
airplanes was published in the Federal Register on May 5, 1998 (63 FR
24760). That action proposed to require repetitive inspections to
detect fatigue cracking of the front spar vertical stringers on the
wings; and repair, if necessary. That action also proposed to provide
for an optional terminating action for the repetitive inspections.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Request To Allow Flight With Known Cracks
One commenter, the manufacturer, requests that the proposed AD be
revised to allow operators to continue operation of an unrepaired
airplane following detection of cracks, utilizing the follow-on
inspections and conditions described in Airbus Service Bulletin A320-
57-1016, Revision 1, dated December 6, 1995. The commenter states that
the follow-on inspection intervals are based on fatigue test results
and calculations of the crack propagation rate, depending on the crack
length. The commenter also states that the structure of the Airbus
Model A320 series airplane is classified as damage tolerant.
Additionally, the commenter notes that the inspection program specified
in the service bulletin was developed in order to prevent the need for
extensive repairs of the aircraft.
The FAA does not concur. It is the FAA's policy to require repair
of known cracks prior to further flight, except in certain cases of
unusual need, as
[[Page 47424]]
discussed below. This policy is based on the fact that such damaged
airplanes do not conform to the FAA certificated type design, and
therefore, are not airworthy until a properly approved repair is
incorporated. While recognizing that repair deferrals may be necessary
at times, the FAA policy is intended to minimize adverse human factors
relating to the lack of reliability of long-term repetitive
inspections, which may reduce the safety of the type certificated
design if such repair deferrals are practiced routinely.
As noted above, the FAA's policy regarding flight with known cracks
does allow deferral of repairs in certain cases, if there is an unusual
need for a temporary deferral. Unusual needs include such circumstances
as legitimate difficulty in acquiring parts to accomplish repairs.
Under such conditions, the FAA may allow a temporary deferral of the
repair, subject to a stringent inspection program acceptable to the
FAA. The FAA acknowledges that the manufacturer has specified
inspection intervals that are intended to allow continued operation
with known cracks, and to prevent the need for extensive repairs.
However, since the FAA is not aware of any unusual need for repair
deferral in regard to this AD, the FAA has not evaluated these
inspection intervals.
Additionally, the FAA policy applies to airplanes certificated to
damage tolerance evaluation regulations as well as those not so
certificated. Therefore, the commenter's statement that ``the Airbus
Model A320 airplane structure is classified as damage tolerant'' is not
relevant to the application of the FAA's policy in this regard.
The FAA considers the compliance times in this AD to be adequate to
allow operators to acquire parts to have on hand in the event that a
crack is detected during inspection. Therefore, the FAA has determined
that, due to the safety implications and consequences associated with
such cracking, any subject bottom flange or fastener hole that is found
to be cracked must be repaired or modified prior to further flight. No
change to the final rule is necessary.
Request To Revise Service Bulletin Dates
One commenter supports the intent of the proposed AD, but requests
that it be revised to reflect the correct issuance date for Revision 1
of Airbus Service Bulletins A320-57-1016 and A320-57-1017. The
commenter states that the correct issuance date for both of these
service bulletins is September 3, 1991. The FAA does not concur. The
original version of these service bulletins is dated September 3, 1991,
rather than Revision 1. Therefore, the FAA finds that no change to the
final rule is necessary.
Conclusion
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule as proposed.
Cost Impact
The FAA estimates that 16 airplanes of U.S. registry will be
affected by this AD, that it will take approximately 2 work hours per
airplane to accomplish the required inspection, and that the average
labor rate is $60 per work hour. Based on these figures, the cost
impact of the inspection required by this AD on U.S. operators is
estimated to be $1,920, or $120 per airplane, per inspection cycle.
The cost impact figure discussed above is based on assumptions that
no operator has yet accomplished any of the requirements of this AD
action, and that no operator would accomplish those actions in the
future if this AD were not adopted.
Should an operator elect to accomplish the optional terminating
modification, rather than continue the repetitive inspections, it would
require approximately 6 work hours to accomplish it, at an average
labor rate of $60 per work hour. Required parts would cost
approximately $700 per airplane. Based on these figures, the cost
impact of the optional terminating modification provided by this AD on
U.S. operators is estimated to be $1,060
Regulatory Impact
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from the Rules Docket at the location provided under the caption
ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
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 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
98-18-26 Airbus Industrie: Amendment 39-10742. Docket 98-NM-18-AD.
Applicability: Model A320 series airplanes on which Airbus
Modification 21290 (reference Airbus Service Bulletin A320-57-1017,
Revision 01, dated March 17, 1997) has not been installed,
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 (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 detect and correct fatigue cracking of the front spar
vertical stringers on the wings, which could result in reduced
structural integrity of the airframe, accomplish the following:
(a) Prior to the accumulation of 24,000 total flight cycles, or
within 60 days after the effective date of this AD, whichever occurs
later: Perform an eddy current inspection to detect fatigue cracking
of the front spar vertical stringers on the wings, in accordance
with Airbus Service Bulletin A320-57-1016, Revision 1, dated
December 6, 1995.
[[Page 47425]]
(1) If no crack is detected, repeat the eddy current inspection
thereafter at intervals not to exceed 14,000 flight cycles.
(2) If any crack is detected, prior to further flight, repair in
accordance with a method approved by the Manager, International
Branch, ANM-116, FAA, Transport Airplane Directorate; or the
Direction Generale de l'Aviation Civile (or its delegated agent).
Thereafter, repeat the eddy current inspection at intervals not to
exceed 14,000 flight cycles.
(b) Modification of the front spar vertical stringers on the
wings, in accordance with Airbus Service Bulletin A320-57-1017,
Revision 01, dated March 17, 1997, 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, International Branch, ANM-116.
Operators shall submit their requests through an appropriate FAA
Principal Maintenance Inspector, who may add comments and then send
it to the Manager, International Branch, ANM-116.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the International Branch, ANM-116.
(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 shall be done in accordance with Airbus
Service Bulletin A320-57-1016, Revision 1, dated December 6, 1995,
which contains the following list of effective pages:
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Revision level Date shown on
Page No. shown on page page
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1-4, 7........................ 1................... Dec. 6, 1995
5-6, 8-13..................... Original............ Sept. 3, 1991
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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. Copies may be obtained from Airbus Industrie, 1 Rond Point
Maurice Bellonte, 31707 Blagnac Cedex, France. 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.
Note 3: The subject of this AD is addressed in French
airworthiness directive 97-311-105(B), dated October 22, 1997.
(f) This amendment becomes effective on October 13, 1998.
Issued in Renton, Washington, on August 28, 1998.
Vi L. Lipski, Acting Manager,
Transport Airplane Directorate,Aircraft Certification Service.
[FR Doc. 98-23738 Filed 9-4-98; 8:45 am]
BILLING CODE 4910-13-P
