[Federal Register Volume 59, Number 72 (Thursday, April 14, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-8056]


[[Page Unknown]]

[Federal Register: April 14, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-148-AD; Amendment 39-8871; AD 94-07-13]

 

Airworthiness Directives; Fokker Model F-28 Mark 0100 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to Fokker Model F-28 Mark 0100 series airplanes, that 
requires inspection, necessary repair, and modification of the engine 
mount shear shelf webs. This amendment is prompted by reports of 
interference between the engine mount shear shelf web and the fixed 
cowl mid and aft hooks, which caused fatigue cracks to occur in the 
web. The actions specified by this AD are intended to prevent fatigue 
cracking and other damage to the structure of the shear shelf web, 
which subsequently could lead to loss of the engine mounting structure.

DATES: Effective May 16, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 16, 1994.

ADDRESSES: The service information referenced in this AD may be 
obtained from Fokker Aircraft USA, Inc., 1199 North Fairfax Street, 
Alexandria, Virginia 22314. This information may be examined at the 
Federal Aviation Administration (FAA), Transport Airplane Directorate, 
Rules Docket, 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: 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: A proposal to amend part 39 of the Federal 
Aviation Regulations to include an airworthiness directive (AD) that is 
applicable to Fokker Model F-28 Mark 0100 series airplanes was 
published in the Federal Register on October 21, 1993 (58 FR 54312). 
That action proposed to require inspection, necessary repair, and 
modification of the engine mount shear shelf webs.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter supports the proposal.
    Two commenters request that proposed paragraph (a)(1) be deleted 
from the rule. That paragraph proposed to require that a detailed 
visual inspection be conducted to detect cracking or other damage of 
the engine mount shear shelf webs around the areas of the fixed cowl 
aft- and mid-hook centerlines. These commenters contend that, since the 
modification required by paragraph (a)(2) reinforces the web and 
eliminates the interference problems, the inspection of this area 
should not be required to be accomplished. The FAA concurs. Since the 
interference problem that prompted this AD action has been found only 
in the area that is to be modified, and since the modification will 
prevent the interference problem and remove any evidence of damage, the 
FAA has determined that the proposed inspection is not necessary. 
Further, if an operator has already performed the proposed 
modification, the FAA finds that it would be an undue burden to require 
that the operator disassemble the modified area to accomplish an 
inspection of it. Additionally, the manufacturer and the one affected 
U.S. operator have advised the FAA that inspection of this area at 
intervals of 1,000 flight hours is already specified in the 
manufacturer's recommended maintenance program. In light of all of 
these factors, the FAA has revised the final rule to delete the 
requirement to inspect the subject area.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the change previously 
described. The FAA has determined that this change will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    The FAA estimates that 20 airplanes of U.S. registry will be 
affected by this AD, that it will take approximately 120 work hours per 
airplane to accomplish the required actions, and that the average labor 
rate is $55 per work hour. Required parts will cost approximately 
$2,390 per airplane. Based on these figures, the total cost impact of 
the AD on U.S. operators is estimated to be $179,800, or $8,990 per 
airplane.
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted. However, the 
FAA has been advised that all 20 affected U.S.-registered airplanes 
have been modified in accordance with the requirements of the AD as of 
December 1993. Therefore, there currently is no economic cost impact of 
this rule on U.S. operators.
    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 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 14 CFR 11.89.


Sec. 39.13  [Amended]

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

94-07-13 Fokker: Amendment 39-8871. Docket 93-NM-148-AD.

    Applicability: Model F-28 Mark 0100 series airplanes; having 
serial numbers 11244 to 11308 inclusive, 11310, 11312, 11313, 11314, 
11316, 11321, 11328, and 11329; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent fatigue cracking and other damage to the engine mount 
shear shelf web, which subsequently could lead to loss of the engine 
mounting structure, accomplish the following:
    (a) Prior to the accumulation of 12,000 total flight hours or 
within 90 days after the effective date of this AD, whichever occurs 
later, modify (reinforce) the engine mount shear shelf webs in 
accordance with Part 1 or Part 2, as applicable, of the 
Accomplishment Instructions of Fokker Service Bulletin SBF100-71-
012, dated February 7, 1992.
    (b) 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, FAA, 
Transport Airplane Directorate, ANM-113. 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.

    (c) 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.
    (d) The modification shall be done in accordance with Fokker 
Service Bulletin SBF100-71-012, dated February 7, 1992. 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 Aircraft USA, Inc., 1199 
North Fairfax Street, Alexandria, Virginia 22314. 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.
    (e) This amendment becomes effective on May 16, 1994.

    Issued in Renton, Washington, on March 30, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-8056 Filed 4-13-94; 8:45 am]
BILLING CODE 4910-13-U