[Federal Register Volume 64, Number 249 (Wednesday, December 29, 1999)]
[Rules and Regulations]
[Pages 72913-72916]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-33567]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NM-235-AD; Amendment 39-11484; AD 99-27-03]
RIN 2120-AA64
Airworthiness Directives; Fokker Model F27 Mark 050 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Fokker Model F27 Mark 050 series airplanes. This
action requires repetitive inspections of the connections between
certain ribs and stringers of the wing skins to detect loose or missing
rivets or gaps, and corrective actions, if necessary. This action also
requires eventual modification of the rib-stringer connection, which
terminates the repetitive inspections. This amendment is prompted by
issuance of mandatory continuing airworthiness information by a foreign
civil airworthiness authority. The actions specified in this AD are
intended to prevent fatigue cracking in the skin and stringers, which
could result in reduced structural integrity of the wings.
DATES: Effective January 13, 2000.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of January 13, 2000.
Comments for inclusion in the Rules Docket must be received on or
before January 28, 2000.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 99-NM-235-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056.
The service information referenced in this AD may be obtained from
Fokker Services B.V., P.O. Box 231, 2150 AE
[[Page 72914]]
Nieuw-Vennep, The Netherlands. 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: The Rijksluchtvaartdienst (RLD), which is
the airworthiness authority for the Netherlands, notified the FAA that
an unsafe condition may exist on certain Fokker Model F27 Mark 050
series airplanes. The RLD advises that rivet heads were missing at the
rib-to-stringer connections of both the upper and lower wing skin.
Investigation revealed that understrength rivets were used in the
affected connections. Such deficient connections reduce the static
buckling strength of the wing skin and may cause fretting of the
stringer. This condition, if not corrected, could result in fatigue
cracking in the skin and stringers, which could result in reduced
structural integrity of the wings.
Explanation of Relevant Service Information
Fokker has issued Service Bulletin SB50-57-019, dated February 27,
1998, which describes procedures for repetitive detailed visual
inspections of the connections between ribs 11260, 11860, 12660, and
13460, and stringers 4, 5, 6, and 7 of the top and bottom wing skins to
detect loose or missing rivets or gaps. The service bulletin also
describes procedures for modification of the rib-stringer connection.
The modification involves reaming the original rivet holes of the rib-
stringer connections, performing a rotating probe eddy current
inspection to detect cracks of these rivet holes, performing corrective
actions for cases where cracking is detected, and installing connecting
angles between the stringers and ribs. The corrective actions include
reaming the diameter of the rivet hole, performing a surface probe eddy
current inspection to detect cracks of the surrounding of each rivet
hole, drilling out rivets, removing connecting angles, and repairing
angles, as applicable. Accomplishment of the modification eliminates
the need for the repetitive inspections.
For cases where cracking is detected during the visual inspection,
the service bulletin describes procedures for accomplishing either of
the following temporary repairs and eventual modification of the rib-
stringer connection (described previously):
Performing a surface probe eddy current inspection to
detect cracks in the surrounding of the rib-stringer connection in the
area of the gap and/or loose or missing rivets; and installing a shim
between the rib-girder and the stringer and new blind rivets, and
repairing the crack; as applicable.
Performing a surface probe eddy current inspection to
detect cracks in the surrounding of the rib-stringer connection in the
area of the gap and/or loose or missing rivet; and installing
connecting angles and repairing the crack; as applicable.
Accomplishment of the actions specified in the service bulletin is
intended to adequately address the identified unsafe condition. The RLD
classified this service bulletin as mandatory and issued Dutch
airworthiness directive BLA 1998-023/2, dated October 30, 1998, in
order to assure the continued airworthiness of these airplanes in the
Netherlands.
FAA's Conclusions
This airplane model is manufactured in the Netherlands and is type
certificated for operation in the United States under the provisions of
section 21.29 of the Federal Aviation Regulations (14 CFR 21.19) and
the applicable bilateral airworthiness agreement. Pursuant to this
bilateral airworthiness agreement, the RLD has kept the FAA informed of
the situation described above. The FAA has examined the findings of the
RLD, reviewed all available information, and determined that AD action
is necessary for products of this type design that are certificated for
operation in the United States.
Explanation of Requirements of the Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other airplanes of the same type design registered
in the United States, this AD requires accomplishment of the actions
specified in the service bulletin described previously, except as
discussed below.
Differences Between Proposed Rule and Service Bulletin
Operators should note that, although the service bulletin specifies
that the manufacturer may be contacted for disposition of certain
repair conditions, this AD requires the repair of those conditions to
be accomplished in accordance with a method approved by the FAA, or the
RLD (or its delegated agent). In light of the type of repair required
to address the identified unsafe condition, and in consonance with
existing bilateral airworthiness agreements, the FAA has determined
that, for this AD, a repair approved by either the FAA or the RLD is
acceptable for compliance with this AD.
Cost Impact
None of the airplanes affected by this action are on the U.S.
Register. All airplanes included in the applicability of this rule
currently are operated by non-U.S. operators under foreign registry;
therefore, they are not directly affected by this AD action. However,
the FAA considers that this rule is necessary to ensure that the unsafe
condition is addressed in the event that any of these subject airplanes
are imported and placed on the U.S. Register in the future.
Should an affected airplane be imported and placed on the U.S.
Register in the future, it would require approximately 11 work hours to
accomplish the required visual inspection, at an average labor rate of
$60 per work hour. Based on these figures, the cost impact of the
visual inspection required by this AD would be $660 per airplane, per
inspection cycle.
Should an affected airplane be imported and placed on the U.S.
Register in the future, it would require approximately between 80 and
116 work hours to accomplish the required modification, at an average
labor rate of $60 per work hour. Required parts would cost
approximately $11,850 per airplane. Based on these figures, the cost
impact of the modification required by this AD would be between $16,650
and $18,810 per airplane.
Determination of Rule's Effective Date
Since this AD action does not affect any airplane that is currently
on the U.S. register, it has no adverse economic impact and imposes no
additional burden on any person. Therefore, prior notice and public
procedures hereon are unnecessary and the amendment may be made
effective in less than 30 days after publication in the Federal
Register.
Comments Invited
Although this action is in the form of a final rule and was not
preceded by notice and opportunity for public comment, comments are
invited on this rule. Interested persons are invited to comment on this
rule by submitting such written data, views, or arguments as they may
desire. Communications shall identify the Rules Docket number
[[Page 72915]]
and be submitted in triplicate to the address specified under the
caption ADDRESSES. All communications received on or before the closing
date for comments will be considered, and this rule may be amended in
light of the comments received. Factual information that supports the
commenter's ideas and suggestions is extremely helpful in evaluating
the effectiveness of the AD action and determining whether additional
rulemaking action would be needed.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the 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 that
summarizes each FAA-public contact concerned with the substance of this
AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this rule must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 99-NM-235-AD.'' The postcard will be date stamped and
returned to the commenter.
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:
99-27-03 Fokker: Amendment 39-11484. Docket 99-NM-235-AD.
Applicability: Model F27 Mark 050 series airplanes, serial
numbers 20103 through 20298 inclusive; 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 (e) 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 fatigue cracking in the skin and stringers, which
could result in reduced structural integrity of the wings,
accomplish the following:
(a) Perform a detailed visual inspection of the connections
between ribs 11260, 11860, 12660, and 13460, and stringers 4, 5, 6,
and 7 of the top and bottom wing skins to detect loose or missing
rivets or gaps, in accordance with Part 1 of Fokker Service Bulletin
SBF50-57-019, dated February 27, 1998; at the time specified in
paragraph (a)(1), (a)(2), (a)(3), or (a)(4) of this AD, as
applicable. Repeat the inspection thereafter at intervals not to
exceed 2,500 flight cycles.
(1) For airplanes that have accumulated less than 15,000 total
flight cycles as of the effective date of this AD: Inspect prior to
the accumulation of 15,000 total flight cycles, or within 12 months
after the effective date of this AD, whichever occurs later.
(2) For airplanes that have accumulated 15,000 total flight
cycles or more but less than 20,000 total flight cycles as of the
effective date of this AD: Inspect within 12 months after the
effective date of this AD.
(3) For airplanes that have accumulated 20,000 total flight
cycles or more but less than 25,000 total flight cycles as of the
effective date of this AD: Inspect within 6 months after the
effective date of this AD.
(4) For airplanes that have accumulated 25,000 total flight
cycles or more as of the effective date of this AD: Inspect within 3
months after the effective date of this AD.
Note 2: For the purposes of this AD, a detailed visual
inspection is defined as: ``An intensive visual examination of a
specific structural area, system, installation, or assembly to
detect damage, failure, or irregularity. Available lighting is
normally supplemented with a direct source of good lighting at
intensity deemed appropriate by the inspector. Inspection aids such
as mirror, magnifying lenses, etc. may be used. Surface cleaning and
elaborate access procedures may be required.''
(b) Except as provided by paragraph (d) of this AD, if no loose
or missing fastener, or no gap is found during any inspection
required by paragraph (a) of this AD, prior to the accumulation of
40,000 total flight cycles, or within 18 months after the effective
date of this AD, whichever occurs later, modify the rib-stringer
connections (i.e., reaming of rivet holes, rotating probe eddy
current inspections, corrective actions, and installation of
connecting angles) in accordance with Part 2 of the Accomplishment
Instructions of Fokker Service Bulletin SBF50-57-019, dated February
27, 1998. Accomplishment of the actions required by this paragraph
constitutes terminating action for the repetitive inspection
requirements of paragraph (a) of this AD.
(c) If any loose or missing fastener, or any gap is found during
any inspection required by paragraph (a) of this AD, prior to
further flight, accomplish the actions specified in paragraph
(c)(1), (c)(2), or (c)(3) of this AD in accordance with Fokker
Service Bulletin SBF50-57-019, dated February 27, 1998.
(1) Accomplish the modification specified in paragraph (b) of
this AD.
(2) Except as provided by paragraph (d) of this AD, accomplish
the temporary repair (i.e., surface probe eddy current inspection,
repair, and installation of a shim and new blind rivets) in
accordance with Part 3 of the Accomplishment Instructions of the
service bulletin. Within 500 flight cycles after accomplishment of
this temporary repair, accomplish the modification specified in
paragraph (b) of this AD.
(3) Except as provided by paragraph (d) of this AD, accomplish
the temporary repair (i.e., surface probe eddy current inspection,
repair, and installation of connecting angles) in accordance with
Part 4 of the Accomplishment Instructions of the service bulletin.
Within 2,500 flight cycles after accomplishment of this temporary
repair, accomplish the modification specified in paragraph (b) of
this AD.
(d) If any discrepancy is found during any inspection required
by paragraph (a), (b), or (c) of this AD; and Fokker Service
Bulletin SBF50-57-019, dated February 27, 1998, specifies to contact
Fokker for appropriate
[[Page 72916]]
action: Prior to further flight, repair in accordance with either a
method approved by the Manager, International Branch, ANM-116, FAA,
Transport Airplane Directorate, or the Rijksluchtvaartdienst (RLD)
(or its delegated agent). For a repair method to be approved by the
Manager, International Branch, ANM-116, as required by this
paragraph, the Manager's approval letter must specifically reference
this AD.
Alternative Methods of Compliance
(e) 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.
Special Flight Permits
(f) 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.
Incorporation by Reference
(g) Except as provided by paragraph (d) of this AD, the actions
shall be done in accordance with Fokker Service Bulletin SBF50-57-
019, dated February 27, 1998. 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
Fokker Services B.V., P.O. Box 231, 2150 AE Nieuw-Vennep, The
Netherlands. 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 Dutch
airworthiness directive 1998-023/2, dated October 30, 1998.
(h) This amendment becomes effective on January 13, 2000.
Issued in Renton, Washington, on December 21, 1999.
D. L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-33567 Filed 12-28-99; 8:45 am]
BILLING CODE 4910-13-U
