[Federal Register Volume 61, Number 218 (Friday, November 8, 1996)]
[Proposed Rules]
[Pages 57832-57834]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-28690]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-154-AD]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F28 Mark 0100 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 F28 Mark 0100 
series airplanes. This proposal would require loosening certain nuts on 
the horizontal stabilizer control unit (HSCU) to reduce stress on 
bolts; a one-time inspection of certain bolts on the HSCU to detect 
cracking, and replacement, if necessary; application of corrosion 
protection to these bolts; and reassembly and reidentification of the 
modified HSCU. This proposal is prompted by reports indicating that 
stress corrosion, resulting from overtightening of nuts on these bolts, 
has caused some of these bolts to crack and fail. The actions specified 
by the proposed AD are intended to prevent failure of these bolts 
because of stress corrosion cracking which, if not corrected, could 
lead to loss of control of the horizontal stabilizer and reduced 
controllability of the airplane.

DATES: Comments must be received by December 20, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-154-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 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: Tim Dulin, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2141; fax (206) 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-154-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. 96-NM-154-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Rijksluchtvaartdienst (RLD), which is the airworthiness 
authority for the Netherlands, recently notified the FAA that an unsafe 
condition may exist on certain Fokker Model F28 Mark 0100 series 
airplanes. The RLD advises that it has received reports indicating that 
lower bolts joining the dog-links to the pistons of the horizontal 
stabilizer control unit (HSCU) have cracked and failed on some 
airplanes. For the dog-links to disconnect from the pistons, both lower 
bolts would have to fail; no disconnections, however, have been 
reported.
    Investigation revealed that overtightening of the nuts on these 
bolts resulted in stress corrosion, which caused bolts to crack and 
fail. This condition, if not corrected, could lead to loss of control 
of the horizontal stabilizer and reduced controllability of the 
airplane.

Explanation of Relevant Service Information

    Fokker has issued Service Bulletin SBF100-27-069, dated January 1, 
1996, as revised by Service Bulletin Change Notification SBF100-27-069/
01, dated January 8, 1996, which describes procedures for loosening 
(reducing the torque value) the nuts on the lower bolts that join the 
dog-links to the pistons of the horizontal stabilizer control unit 
(HSCU); a one-time inspection of these bolts to detect cracking, and 
replacement of discrepant bolts with serviceable bolts; application of 
corrosion protection to these bolts; and reassembly and 
reidentification of the HSCU that has been modified. The service 
bulletin references Menasco Aerospace Ltd. Service Bulletin 23100-27-
19, dated November 10, 1995, as an additional source of service 
information for these procedures. The RLD classified the Fokker service 
bulletin, Fokker service bulletin change notification, and Menasco 
Aerospace Ltd. service bulletin as mandatory, and issued Netherlands 
airworthiness directive BLA 1996-006 (A), dated January 31, 1996, 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

[[Page 57833]]

loosening of nuts on lower bolts that join the dog-links to the pistons 
of the HSCU; a one-time inspection of these bolts to detect cracking, 
and replacement of discrepant bolts with serviceable bolts; application 
of corrosion protection to these bolts; and reassembly and 
reidentification of the HSCU that has been modified. (Some airplanes 
were modified on the production line, but the HSCU was not 
reidentified. This proposal would require that the HSCU on those 
airplanes also be reidentified.).
    The proposed actions would be required to be accomplished in 
accordance with the service bulletins and service bulletin change 
notification described previously.

Cost Impact

    The FAA estimates that 125 Fokker Model F28 Mark 0100 series 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 5 work hours per airplane to accomplish the 
proposed loosening of nuts, and that the average labor rate is $60 per 
work hour. Based on these figures, the cost impact of the proposed AD 
on U.S. operators is estimated to be $37,500, or $300 per airplane.
    The FAA also estimates that it would take approximately 6 work 
hours per airplane to accomplish the proposed inspection, apply 
corrosion protection to the bolts, and reassemble and reidentify the 
HSCU. The average labor rate is $60 per work hour. Based on these 
figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $45,000, or $360 per airplane.
    There currently are no known airplanes of U.S. registry that would 
be required to accomplish the proposed reidentification of the HSCU 
because the HSCU was modified on the production line and not 
reidentified.
    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-154-AD.

    Applicability: Model F28 Mark 100 series airplanes, as listed in 
Fokker Service Bulletin SBF100-27-069, dated January 1, 1996; 
certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 failure of the lower bolts that join the dog-links to 
the piston of the horizontal stabilizer control unit (HSCU) because 
of stress corrosion cracking, which could result in loss of control 
of the horizontal stabilizer and reduced controllability of the 
airplane, accomplish the following:
    (a) Within 3 months after the effective date of this AD, loosen 
the nut [part number (P/N) MS17825-10] on each lower bolt (P/N 
23233-1) that joins the dog-links to the piston of the HSCU, in 
accordance with Part 1 of the Accomplishment Instructions of Fokker 
Service Bulletin SBF100-27-069, dated January 1, 1996, as revised by 
Part 1 of Fokker Service Bulletin Change Notification SBF100-27-069/
01, dated January 8, 1996; and Part A of the Accomplishment 
Instructions of Menasco Aerospace Ltd. Service Bulletin 23100-27-19, 
dated November 10, 1995.
    (b) Within 6 months after the effective date of this AD, inspect 
each lower bolt (P/N 23233-1) that joins the dog-links to the 
pistons of the HSCU to detect cracking and failure, in accordance 
with the Part 2 of the Accomplishment Instructions of Fokker Service 
Bulletin SBF100-27-069, dated January 1, 1996, as revised by Part 2 
of Fokker Service Bulletin Change Notification SBF100-27-069/01, 
dated January 8, 1996; and Part B of the Accomplishment Instructions 
of Menasco Aerospace Ltd. Service Bulletin 23100-27-19, dated 
November 10, 1995.
    (1) If no cracking or failure is detected, prior to further 
flight, apply corrosion protection to each bolt, and reassemble and 
reidentify the HSCU, in accordance with Part 2 of the Accomplishment 
Instructions of Fokker Service Bulletin SBF100-27-069, dated January 
1, 1996, as revised by Part 2 of Fokker Service Bulletin Change 
Notification SBF100-27-069/01, dated January 8, 1996; and Part B of 
the Accomplishment Instructions of Menasco Aerospace Ltd. Service 
Bulletin 23100-27-19, dated November 10, 1995.
    (2) If any cracking or failure is detected, prior to further 
flight, replace the discrepant bolt with a serviceable bolt, apply 
corrosion protection to each serviceable bolt, and reassemble and 
identify the HSCU, in accordance with Part 2 of the Accomplishment 
Instructions of Fokker Service Bulletin SBF100-27-069, dated January 
1, 1996, as revised by Part 2 of Fokker Service Bulletin Change 
Notification SBF100-27-069/01, dated January 8, 1996; and Part B of 
the Accomplishment Instructions of Menasco Aerospace Ltd. Service 
Bulletin 23100-27-19, dated November 10, 1995.
    (c) For airplanes having serial numbers 11500, 11505, and 11511: 
Within 6 months after the effective date of this AD, reidentify the 
HSCU in accordance with Part 3 of the Accomplishment Instructions of 
Fokker Service Bulletin SBF100-27-069, dated January 1, 1996.
    (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, Standardization Branch, ANM-113, 
FAA, Transport Airplane Directorate. Operators shall submit their 
requests through an appropriate FAA Principal Maintenance

[[Page 57834]]

Inspector, who may add comments and then send it to the Manager, 
Standardization Branch, ANM-113.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (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.

    Issued in Renton, Washington, on November 1, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-28690 Filed 11-7-96; 8:45 am]
BILLING CODE 4910-13-U