[Federal Register Volume 59, Number 27 (Wednesday, February 9, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-2917]


[[Page Unknown]]

[Federal Register: February 9, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-201-AD]

 

Airworthiness Directives; Fokker Model F27 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 Model F27 series 
airplanes. This proposal would require replacement of certain bolts 
that are currently installed in various flight critical components of 
the airplane. This proposal is prompted by reports of incidents 
involving corrosion and fatigue cracking in transport category 
airplanes that are approaching or have exceeded their economic design 
goal; these incidents have jeopardized the airworthiness of the 
affected airplanes. The actions specified by the proposed AD are 
intended to prevent reduced structural integrity of various flight 
critical components of the airplane.

DATES: Comments must be received by April 5, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 93-NM-201-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Fokker Aircraft USA, Inc., 1199 North Fairfax Street, 
Alexandria, Virginia 22314. This information may be examined at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Mark Quam, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2145; fax (206) 227-1320.

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 93-NM-201-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-103, Attention: Rules 
Docket No. 93-NM-201-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    In April 1988, a high-cycle transport category airplane 
(specifically, a Boeing Model 737) was involved in an accident in which 
the airplane suffered major structural damage during flight. 
Investigation of this accident revealed that the airplane had numerous 
fatigue cracks and a great deal of corrosion. Subsequent inspections 
conducted by the operator on other high-cycle transport category 
airplanes in its fleet revealed that other airplanes had extensive 
fatigue cracking and corrosion.
    Prompted by the data gained from this accident, the FAA sponsored a 
conference on aging airplanes in June 1988, which was attended by 
representatives from the aviation industry and airworthiness 
authorities from around the world. Because of the tremendous increase 
in air travel, the relatively slow pace of new airplane production, and 
the apparent economic feasibility of operating older technology 
airplanes rather than retiring them, increased attention needs to be 
focused on the aging airplane fleet to maintain its continued 
operational safety.
    The Air Transport Association (ATA) of America and the Aerospace 
Industries Association (AIA) of America agreed to undertake the task of 
identifying and implementing procedures to ensure the continued 
structural airworthiness of aging transport category airplanes. An 
Airworthiness Assurance Task Force (AATF) was established in August 
1988, with members representing aircraft manufacturers, operators, 
regulatory authorities, and other aviation industry representatives 
worldwide. The objective of the AATF was to sponsor ``Working Groups'' 
to:
    1. Select service bulletins, applicable to each airplane model in 
the transport fleet, to be recommended for mandatory modification of 
aging airplanes;
    2. Develop corrosion-directed inspections and prevention programs;
    3. Review the adequacy of each operator's structural maintenance 
program;
    4. Review and update the Supplemental Inspection Program (SIP); and
    5. Assess repair quality.
    The Working Group assigned to review the Fokker Model F27 series 
airplanes has completed its work on Item (1), above. The Working Group 
has identified certain service difficulties that warrant mandatory 
modification of these airplanes. The Working Group considers that these 
service difficulties warrant mandatory modification of the airplane to 
assure continued operational safety of Model F27 airplanes that have 
exceeded their economic design goal.
    The ``economic design goal'' of an airplane is typically considered 
to be the period of service after which a substantial increase in the 
maintenance costs is expected to take place in order to assure 
continued operational safety. The economic design goal for Fokker Model 
F27 series airplanes is 20 years for structural problems associated 
with environmental deterioration, and 60,000 flight cycles for 
structural problems associated with fatigue damage.
    The Working Group has recommended Fokker Service Bulletin F27/51-
10, Revision 2, dated June 12, 1993, for mandatory modification. This 
service bulletin describes procedures for replacement of AN bolts that 
are currently installed in the following flight critical components of 
the airplane with NAS bolts. The manufacturing process used to produce 
NAS bolts yields superior quality bolts that are anticipated to 
preclude cracking in these areas:
    1. Flight controls (including the push-pull rods of the trim drive 
mechanism; aileron, rudder, elevator, and elevator trim tab controls; 
and elevator hinge support assemblies).
    2. Control surfaces (including elevator, rudder, aileron, and tab 
hinge bolts).
    3. Fuel control installations.
    4. Engine mount and nacelle brace installations.
    5. Engine control installations.
    This service bulletin has been amended by Service Bulletin Change 
Notification F27/51 - 10REV2/01, dated October 1, 1993, to correct an 
error in a part number referenced in the service bulletin.
    The Rijksluchtvaartdienst (RLD), which is the airworthiness 
authority for the Netherlands, classified the original release of the 
service bulletin as mandatory and issued Netherlands Airworthiness 
Directive (BLA) 91-111, dated September 13, 1991, in order to assure 
the continued airworthiness of these airplanes in the Netherlands.
    This airplane model is manufactured in the Netherlands and is type 
certificated for operation in the United States under the provisions of 
Sec. 21.29 of the Federal Aviation Regulations 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.
    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 replacement of AN 
bolts that are currently installed in various flight critical 
components of the airplane with NAS bolts. The actions would be 
required to be accomplished in accordance with the service bulletin 
described previously.
    The proposed compliance time for implementation of this 
modification program is within 3 years after the effective date of the 
AD. This time interval was based upon the ability of the manufacturer 
to provide the parts necessary for the modification, and the time 
necessary to incorporate the modification.
    In the interim, safety will be provided by various means currently 
in place that are considered satisfactory to detect damage prior to the 
occurrence of an unsafe condition. These include operators' ongoing 
basic maintenance programs; continuing inspections required by numerous 
AD's issued previously; the SIP mandated by AD 92-19-07, Amendment 39-
8365 (57 FR 42693, September 16, 1992); the FAA's increased emphasis on 
surveillance of operators' maintenance programs and procedures; and the 
FAA's participation in programs to physically inspect high-time 
airplanes during scheduled heavy maintenance.
    The FAA estimates that 39 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 250 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $55 per work hour. Required parts would cost 
approximately $690 per airplane. Based on these figures, the total cost 
impact of the proposed AD on U.S. operators is estimated to be 
$563,160, or $14,440 per airplane. This total cost figure assumes that 
no operator has yet accomplished the proposed requirements of this AD 
action.
    The FAA recognizes that the proposed modification would require a 
large number of work hours to accomplish. However, the 3-year 
compliance time specified in paragraph (a) of this proposed AD should 
allow ample time for the replacement of AN bolts to be accomplished 
coincidentally with scheduled major airplane inspection and maintenance 
activities, thereby minimizing the costs associated with special 
airplane scheduling.
    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 14 
CFR part 39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES-

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14a CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Fokker: Docket 93-NM-201-AD.

    Applicability: Model F27 series airplanes, having serial numbers 
10102 through 10612 inclusive; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent reduced structural integrity of various flight 
critical components of the airplane, accomplish the following:
    (a) Within 3 years after the effective date of this AD, remove 
AN bolts that are currently installed in the flight controls, 
control surfaces, fuel control installations, engine mount and 
nacelle brace installations, and engine control installations, and 
replace them with NAS 1303/1320 bolts, in accordance with Fokker 
Service Bulletin F27/51-10, Revision 2, dated June 12, 1993, as 
amended by Service Bulletin Change Notification F27/51 - 10REV2/01, 
dated October 1, 1993.
    (b) As of the effective date of this AD, no person shall install 
on any airplane any AN bolt having a part number that is listed in 
Fokker Service Bulletin F27/51-10, Revision 2, dated June 12, 1993, 
as amended by Service Bulletin Change Notification F27/51 - 10REV2/
01, dated October 1, 1993, in any of the flight critical components 
identified in the service bulletin.
    (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, Standardization Branch, ANM-113, 
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, 
Standardization Branch, ANM-113.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (d) Special flight permits may be issued in accordance with 
Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the 
airplane to a location where the requirements of this AD can be 
accomplished.

    Issued in Renton, Washington, on February 3, 1994.
N. B. Martenson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-2917 Filed 2-8-94; 8:45 am]
BILLING CODE 4910-13-U