[Federal Register Volume 63, Number 29 (Thursday, February 12, 1998)]
[Proposed Rules]
[Pages 7078-7080]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-3514]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-186-AD]
RIN 2120-AA64


Airworthiness Directives; Fokker F27 Mark 100, 200, 300, 400, 
500, 600, and 700 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Fokker F27 Mark 100, 200, 
300, 400, 500, 600, and 700 series airplanes. This proposal would 
require a modification of the lapjoint below the chine line at certain 
fuselage stations. This proposal is prompted by issuance of mandatory 
continuing airworthiness information by a foreign civil airworthiness 
authority. The actions specified by the proposed AD are intended to 
prevent fatigue cracking in the lapjoint below the chine line at 
certain fuselage stations, which could result in reduced structural 
integrity of the fuselage.

DATES: Comments must be received by March 16, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 96-NM-186-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 Fokker Services B.V., Technical Support Department, P.O. 
Box 75047, 1117 ZN Schiphol Airport, the Netherlands. This information 
may be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington.

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:

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 96-NM-186-AD.'' The 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. 96-NM-186-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Rijksluchtvaartdienst (RLD), which is the airworthiness 
authority for the Netherlands, notified the FAA that an unsafe 
condition may exist on certain Fokker F27 Mark 100, 200, 300, 400, 500, 
600, and 700 series airplanes. The RLD advises that fatigue analysis of 
Fokker Model F27 series airplanes has shown that the lapjoints below 
the chine line, between fuselage station 1400 and 16660, are vulnerable 
to multiple-site fatigue cracking. Such fatigue cracking occurs when 
the airplane is operated, or has been operated, at 5.5 pounds per 
square inch (psi) differential cabin pressure, and the affected bottom 
fuselage skin panels have a thickness of 0.6 millimeters (mm) (between 
fuselage station 1400 and station 12975) or 0.7 mm (between fuselage 
station 12975 and station 16660). This condition, if not detected and 
corrected in a timely manner, could result in reduced structural 
integrity of the fuselage.

Other Relevant Rulemaking

    The FAA has previously issued AD 96-13-07, amendment 39-9675 (61 FR 
34718, July 3, 1996), which currently requires repetitive inspections 
of the subject lapjoints below the chine line of certain fuselage 
stations. These inspections are conducted as part of the Fokker Model 
F27 Structural Integrity Program (SIP).
    This proposed AD will affect items 53-30-02, 53-30-03, and 53-30-04 
of the Fokker Model F27 SIP.

[[Page 7079]]

Explanation of Relevant Service Information

    Fokker has issued Service Bulletin F27/53-116, dated April 15, 
1994, which describes procedures for modification of the lapjoint below 
the chine line between fuselage stations 1400 and 16660. The 
modification involves the installation of an external doubler on top of 
the lapjoint, which would eliminate the need for certain repetitive 
inspections required by AD 96-13-07. The RLD classified this service 
bulletin as mandatory and issued Dutch airworthiness directive BLA 94-
092 (A), dated May 25, 1994, 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 21.29) 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 Proposed 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, the proposed AD would require accomplishment of 
the actions specified in the service bulletin described previously, 
except as described below.

Differences Between the Proposed AD and the Related Dutch AD

    Operators should note that, unlike the parallel Dutch airworthiness 
directive 94-092(A), dated May 25, 1994, the proposed AD does not 
provide for an option for operators to adjust the compliance time 
threshold for the subject modification based on the amount of time the 
airplane has been operating at a maximum cabin pressure differential of 
5.5 psi. The proposed AD would require a fixed threshold for performing 
the modifications to the lapjoints. The FAA has determined that such 
adjustments would not address the unsafe condition in a timely manner. 
However, the FAA acknowledges that the duration of time that the 
airplane was operated at 5.5 psi differential pressure is a 
contributing factor in determining the appropriate threshold. Paragraph 
(d) of the final rule does provide affected operators the opportunity 
to apply for an adjustment of the compliance time if data are presented 
to justify such an adjustment.

Cost Impact

    The FAA estimates that 34 airplanes of U.S. registry would be 
affected by this proposed AD.
    It would take approximately 140 work hours per airplane to 
accomplish the modification (specified as Part 1 in the referenced 
service bulletin), at an average labor rate of $60 per work hour. The 
cost of required parts would be nominal. Based on these figures, the 
cost impact of this modification proposed by this AD on U.S. operators 
is estimated to be $8,400 per airplane.
    It would take approximately 300 work hours per airplane to 
accomplish the modification (specified as Part 2 in the referenced 
service bulletin), at an average labor rate of $60 per work hour. The 
cost of required parts would be nominal. Based on these figures, the 
cost impact of this modification proposed by this AD on U.S. operators 
is estimated to be $18,000 per airplane.
    It would take approximately 210 work hours per airplane to 
accomplish the modification (specified as Part 3 in the referenced 
service bulletin), at an average labor rate of $60 per work hour. The 
cost of required parts would be nominal. Based on these figures, the 
cost impact of this modification proposed by this AD on U.S. operators 
is estimated to be $12,600 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the 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 adding the following new 
airworthiness directive:

Fokker: Docket 96-NM-186-AD.

    Applicability: Model F27 Mark 100, 200, 300, 400, 500, 600, and 
700 series airplanes, serial numbers 10102 through 10375 inclusive, 
that are operated or have been operated at a maximum cabin pressure 
differential of 5.5 pounds per square inch (psi), 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 (d) 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 lapjoint below the chine line 
at certain fuselage stations, which could result in reduced 
structural integrity of the fuselage, accomplish the following:
    (a) For airplanes on which Fokker Service Bulletin F27/53-68, 
dated July 4, 1966, or Revision 1, dated July 19, 1967, has not been

[[Page 7080]]

accomplished: Prior to the accumulation of 32,000 total flight 
cycles, or within 2 years after the effective date of this AD, 
whichever occurs later, modify the lapjoint below the chine line 
between fuselage station 1400 and station 5050, in accordance with 
Part 1 of the Accomplishment Instructions of Fokker Service Bulletin 
F27/53-116, dated April 15, 1994. Accomplishment of this 
modification and accomplishment of the requirements of paragraph (b) 
of this AD, constitutes terminating action for the repetitive 
inspection requirements of items 53-30-02 and 53-30-03 of the Fokker 
Model F27 Structural Inspection Program (SIP), as required by AD 96-
13-07, amendment 39-9675.
    (b) For airplanes on which Fokker Service Bulletin F27/53-85, 
dated February 16, 1970, has not been accomplished: Prior to the 
accumulation of 32,000 total flight cycles, or within 2 years after 
the effective date of this AD, whichever occurs later, modify the 
lapjoint below the chine line between fuselage station 5050 and 
station 12975, in accordance with Part 2 of the Accomplishment 
Instructions of Fokker Service Bulletin F27/53-116, dated April 15, 
1994. Accomplishment of this modification and accomplishment of the 
requirements of paragraph (a) of this AD, constitutes terminating 
action for the repetitive inspection requirements of items 53-30-02 
and 53-30-03 of the Fokker Model F27 SIP, as required by AD 96-13-
07.
    (c) For airplanes on which Fokker Service Bulletin F27/53-85, 
dated February 16, 1970, has not been accomplished: Prior to the 
accumulation of 56,000 total flight cycles, or within 2 years after 
the effective date of this AD, whichever occurs later, modify the 
lapjoint below the chine line between fuselage station 12975 and 
station 16660, in accordance with Part 3 of the Accomplishment 
Instructions of Fokker Service Bulletin F27/53-116, dated April 15, 
1994. Accomplishment of this modification constitutes terminating 
action for the repetitive inspection requirements of item 53-30-04 
of the Fokker Model F27 SIP, as required by AD 96-13-07.
    (d) 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, FAA, 
Transport Airplane Directorate. 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.

    (e) 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.

    Note 3: The subject of this AD is addressed in Dutch 
airworthiness directive BLA 94-092 (A), dated May 25, 1994.

    Issued in Renton, Washington, on February 5, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-3514 Filed 2-11-98; 8:45 am]
BILLING CODE 4910-13-U