[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