[Federal Register Volume 63, Number 136 (Thursday, July 16, 1998)]
[Rules and Regulations]
[Pages 38289-38290]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-18770]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-02-AD; Amendment 39-10659; AD 98-15-08]
RIN 2120-AA64
Airworthiness Directives; British Aerospace Model BAe 146 and
Model Avro 146-RJ 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 British Aerospace Model BAe 146 and Model Avro
146-RJ series airplanes, that requires repetitive detailed visual
inspections of the top wing skins for stress corrosion cracks, damage,
or missing surface protective finish of the metallic surfaces; and
repair, if necessary. This amendment is prompted by reports of stress
corrosion cracks found on the top wing skin during routine inspection
on three airplanes. The actions specified by this AD are intended to
detect and correct such cracking, which could result in reduced
structural integrity of the wing.
DATES: Effective August 20, 1998.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of August 20, 1998.
ADDRESSES: The service information referenced in this AD may be
obtained from AI(R) American Support, Inc., 13850 Mclearen Road,
Herndon, Virginia 20171. This information may be examined 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.
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 British Aerospace Model
BAe 146 and Model Avro 146-RJ series airplanes was published in the
Federal Register on June 17, 1997 (62 FR 32701). That action proposed
to require repetitive detailed visual inspections of the top wing skins
for stress corrosion cracks, damage, or missing surface protective
finish of the metallic surfaces, and repair, if necessary.
Consideration of Comments
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the single comment received.
Components Made of 7150-T651 Aluminum Material
The commenter supports the proposed AD. However, the commenter
expresses a concern that other airplane components made from the same
material could pose a similar problem. As a result, the commenter
requests the FAA to accomplish the following actions:
--Identify any other aircraft components made from the same material.
--Review the inspection criteria and frequency for those applications.
--Ensure that a failure of the material will be detected prior to the
failure posing a risk to continued flight safety.
The FAA acknowledges the concerns of the commenter. Based on
additional information from the manufacturer, the FAA has determined
that the problem is limited to a discrepant production lot of 7150-T651
aluminum material that was produced with the incorrect thickness for
the wing skins. In addition, the FAA has determined that no other
components made of this aluminum material are affected. In light of
this information, the FAA finds that it is unnecessary to take any
additional action, and that the actions required by this AD are
adequate in order to ensure the continued safety of the fleet.
Explanation of New Service Information
Since the issuance of the proposed AD, the manufacturer issued
British Aerospace Service Bulletin SB.57-49, Revision 1, dated June 19,
1997, which replaces British Aerospace Service Bulletin SB.57-49, dated
June 4, 1996. Revision 1 reduces the effectivity specified in the
previous service bulletin to those airplanes on which 7150-T651
aluminum material from a discrepant production lot was used for the top
wing skins. The discrepant material was manufactured with an
inappropriate thickness, which causes the wings to be susceptible to
early stress corrosion cracking on the top wing skin, and which could
result in reduced structural integrity of the airplane wing. However,
since the discovery of this problem, subsequent 7150-T651 aluminum
material used for the top wing skins has been machined to the
appropriate thickness and, as a result, is not susceptible to early
stress corrosion cracking. In all other respects, Revision 1 of the
service bulletin is essentially the same as the original issue of the
service bulletin.
The FAA has reduced the applicability of this final rule to those
airplanes having wing skins made from 7150-T651 aluminum material, as
specified in British Aerospace Service Bulletin SB.57-49, Revision 1,
dated June 19, 1997. In addition, the FAA has revised paragraph (a) of
the final rule to require accomplishment of those actions in accordance
with either the original service bulletin or Revision 1.
Conclusion
After careful review of the available data, including the comments
noted above, the FAA has determined that air
[[Page 38290]]
safety and the public interest require the adoption of the rule with
the changes described previously. The FAA has determined that these
changes will neither increase the economic burden on any operator nor
increase the scope of the AD.
Cost Impact
The FAA estimates that 12 British Aerospace Model BAe 146 and Model
Avro 146-RJ series airplanes of U.S. registry will be affected by this
AD, that it will take approximately 4 work hours per airplane to
accomplish the required actions, and that the average labor rate is $60
per work hour. Based on these figures, the cost impact of the AD on
U.S. operators is estimated to be $2,880, or $240 per airplane.
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.
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:
98-15-08 British Aerospace Regional Aircraft (Formerly British
Aerospace Regional Aircraft Limited, Avro International Aerospace
Division; British Aerospace, PLC; British Aerospace Commercial
Aircraft Limited): Amendment 39-10659. Docket 97-NM-02-AD.
Applicability: Model BAe 146 and Model Avro 146-RJ series
airplanes, as listed in British Aerospace Service Bulletin SB.57-49,
Revision 1, dated June 19, 1997, and having wing skins made from
7150-T651 aluminum; certificated in any category.
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 (b) 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 stress corrosion cracking in the wing
skin, which could result in reduced structural integrity of the
wing, accomplish the following:
(a) Within 4 months after the effective date of this AD; and
thereafter at intervals not to exceed 4,000 landings or 2 years,
whichever occurs first: Perform a detailed visual inspection of the
top wing skins to detect stress corrosion cracking, and any damaged
or missing surface protective finish that exposes the metallic
surfaces, in accordance with British Aerospace Service Bulletin
SB.57-49, dated June 4, 1996, or Revision 1, dated June 19, 1997.
(1) If any damaged or missing surface protective finish is
detected, and no cracking or corrosion is detected, prior to further
flight, reapply the protective finish in accordance with the service
bulletin. Repeat the detailed visual inspection, thereafter, at
intervals not to exceed 4,000 landings or 2 years, whichever occurs
first.
(2) If any cracking is detected, prior to further flight, repair
in accordance with a method approved by the Manager, International
Branch, ANM-116, FAA, Transport Airplane Directorate.
Note 2: During the detailed visual inspections of the top wing
skins, pay particular attention to the edge of cutouts, skin edges,
and attachment bolt holes.
(b) 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 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the International Branch, ANM-116.
(c) 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.
(d) Except as provided by paragraph (a)(2) of this AD, the
inspections and repairs shall be done in accordance with British
Aerospace Service Bulletin SB.57-49, dated June 4, 1996; or British
Aerospace Service Bulletin SB.57-49, Revision 1, dated June 19,
1997. 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 AI(R) American Support, Inc.,
13850 Mclearen Road, Herndon, Virginia 20171. 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 4: The subject of this AD is addressed in British
airworthiness directive 005-06-96, dated June 4, 1996.
(e) This amendment becomes effective on August 20, 1998.
Issued in Renton, Washington, on July 8, 1998.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-18770 Filed 7-15-98; 8:45 am]
BILLING CODE 4910-13-U
