[Federal Register Volume 61, Number 175 (Monday, September 9, 1996)]
[Proposed Rules]
[Pages 47462-47465]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-22920]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-NM-193-AD]
RIN 2120-AA64
Airworthiness Directives; Fokker Model F28 Mark 0100 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Supplemental notice of proposed rulemaking; reopening of
comment period.
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SUMMARY: This document revises an earlier proposed airworthiness
directive (AD) that is applicable to certain Fokker Model F28 Mark 0100
series airplanes. That proposal would have required repetitive
inspections to detect corrosion in the wheel axles of the main landing
gear (MLG) sliding members; and rework of any corroded areas, an
inspection to detect cracks in the wheel axles, and replacement of any
cracked sliding member. That proposal was prompted by a report of
failure of a MLG wheel axle during push back of an in-service airplane
from the terminal. This action revises the proposed rule by providing
for interim actions that may be accomplished in lieu of the repetitive
inspections. This action also revises the proposed rule by requiring
eventual modifications of the main wheel brake units and the MLG
sliding members; when accomplished, these modifications terminate the
repetitive inspections and interim actions. The actions specified by
this proposed AD are intended to prevent failure of the MLG wheel axle
due to problems associated with corrosion and cracking.
DATES: Comments must be received by October 3, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 93-NM-193-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: Ruth E. Harder, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-1721; 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 93-NM-193-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-193-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39) to add an airworthiness directive (AD), applicable to
certain Fokker Model F28 Mark 0100 series airplanes, was published as a
notice of proposed rulemaking (NPRM) in the Federal Register on
February 2, 1994 (59 FR 4875). That NPRM would have required repetitive
inspections to detect corrosion in the wheel axles of the main landing
gear (MLG) sliding members; and rework of any corroded areas, an
inspection to detect cracks in the wheel axles, and replacement of any
cracked sliding member. That NPRM was prompted by a report that a MLG
wheel axle failed during push back of an in-
[[Page 47463]]
service airplane from the terminal. That condition, if not corrected,
could result in failure of the MLG wheel axle due to the problems
associated with corrosion and cracking.
Actions Since Issuance of Previous Proposal
Since the issuance of the NPRM, three new or revised service
bulletins have been released. These service bulletins are described
below.
1. Dowty Aerospace has issued Service Bulletin F100-32-64, Revision
1, dated February 18, 1994. The original issue of this service bulletin
was cited in the NPRM as an appropriate source of service information
for accomplishment of repetitive visual inspections to detect corrosion
in the wheel axles of the MLG sliding members. Although Revision 1 is
essentially the same as the original issue, it contains certain
editorial changes; the technical content of the service bulletin has
not been changed.
2. Fokker has issued Service Bulletin SBF100-32-083, dated March
23, 1994. This service bulletin describes procedures for interim
actions that may be accomplished in lieu of the repetitive inspections
described in Fokker Service Bulletin SBF100-32-080. Accomplishment of
these interim actions would allow an operator to increase the
repetitive inspection interval for its fleet from 3 months to one year
until terminating modifications are accomplished. The interim actions
include:
--Installation of main wheel brake units with chamfered and cadmium-
plated inboard bushings;
--Restoration of the protection scheme of the sliding members; and
--Inspections (also referred to as a ``sampling program'') to detect
corrosion in the wheel axles of the MLG sliding members.
This service bulletin recommends that if any sampling is
unsatisfactory, the repetitive inspections described in Fokker Service
Bulletin SBF100-32-080 should be resumed. (Additionally, this service
bulletin references Part B of the Dowty service bulletin described
previously as an additional source of service information for
accomplishment of the interim actions.)
3. Fokker also has issued Service Bulletin SBF100-32-081, dated
March 23, 1994, which describes procedures for modifications of the
main wheel brake units and the MLG sliding members. These modifications
entail installing the main wheel brake units with chamfered and
cadmium-plated inboard bushings, and installing landing gears with
chromium or nickel plating on the brake abutment flange of the sliding
member and restored cadmium plating and paint in the radius of the
sliding member. Accomplishment of these modifications will prevent the
development of corrosion in the radii of the wheel axles of the MLG
sliding members. Accomplishment of the modifications eliminates the
need for the repetitive inspections and the interim actions.
(Additionally, the Fokker service bulletin references Part C of the
Dowty service bulletin described previously as an additional source of
service information for accomplishment of the modifications.)
Related Action by the Netherlands Authorities
The Rijksluchtvaartdienst (RLD), which is the airworthiness
authority for the Netherlands, has approved the Fokker service
bulletins, and issued Netherlands airworthiness directive (BLA) 93-108/
3 (A), dated April 29, 1994, in order to assure the continued
airworthiness of these airplanes in the Netherlands.
The BLA requires the accomplishment of either the repetitive visual
inspections for corrosion, or the interim actions (including the
`sampling program'' inspections).
FAA's Findings; New Proposed Requirements
The FAA examined the findings of the RLD, and reviewed the latest
service information. The FAA finds that the previously issued NPRM must
be revised to provide for interim actions that may be accomplished in
lieu of the repetitive inspections, and to require the accomplishment
of the modifications of the main wheel brake units and the MLG sliding
members specified in Fokker Service Bulletin SBF100-32-081, dated March
23, 1994. Two new paragraphs have been added to this supplemental NPRM
to provide for these interim actions and to require the modifications
that constitute terminating action for the inspections.
The FAA also has revised the NPRM to cite the latest service
bulletin revisions as the appropriate sources of service information.
Differences Between Proposed Rule and Netherlands Directive
Although the Netherlands BLA does not mandate the accomplishment of
the modifications, this proposed AD would require that those
modifications be accomplished. The FAA has determined that long term
continued operational safety will be better assured by design changes
to remove the source of the problem, rather than by repetitive
inspections. Long term inspections may not be providing the degree of
safety assurance necessary for the transport airplane fleet. This,
coupled with a better understanding of the human factors associated
with numerous continual inspections, has led the FAA to consider
placing less emphasis on inspections and more emphasis on design
improvements. The proposed modification requirement is in consonance
with these considerations.
Conclusion
Since these changes expand the scope of the originally proposed
rule, the FAA has determined that it is necessary to reopen the comment
period to provide additional opportunity for public comment.
Cost Impact
The cost impact information specified in the NPRM indicated that
100 airplanes of U.S. registry would be affected by this proposed AD.
The FAA has updated that information, below, to indicate that 125
airplanes would be affected.
In addition, the FAA has recently reviewed the figures it has used
over the past several years in calculating the economic impact of AD
activity. In order to account for various inflationary costs in the
airline industry, the FAA has determined that it is necessary to
increase the labor rate used in these calculations from $55 per work
hour to $60 per work hour. The cost impact information also has been
revised to reflect this increase in the specified hourly labor rate.
The FAA estimates that 125 airplanes of U.S. registry would be
affected by this proposed AD, that it would take approximately 14 work
hours per airplane to accomplish the proposed visual inspections, and
that the average labor rate is $60 per work hour. Based on these
figures, the cost impact of the initial visual inspection of this
proposed AD on U.S. operators is estimated to be $105,000, or $840 per
airplane.
The FAA estimates that it would take approximately 66 work hours
per airplane to accomplished the proposed terminating modifications, at
an average labor rate of $60 per work hour. The cost for required parts
would be approximately $865 per airplane. Based on these figures, the
cost impact of the proposed terminating action on U.S. operators is
estimated to be $603,125, or $4,825 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
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action, and that no operator would accomplish those actions in the
future if this AD were not adopted.
Should an operator elect to accomplish the repetitive visual
inspections that would be provided by this AD action, it would take
approximately 14 work hours to accomplish each repetitive inspection,
at an average labor rate of $60 per work hour. The FAA estimates that
these inspections would be accomplished four times per year. Based on
these figures, the cost impact of the repetitive inspections on U.S.
operators is estimated to be $3,360 per airplane, per year.
Should an operator elect to accomplish the interim actions that
would be provided by this AD action, it would take approximately 26
work hours for the rework, and 26 work hours per airplane for the brake
unit replacement. It would take between 28-168 work hours per year for
the sampling program, depending on the size of an operator's fleet. The
average labor rate is $60 per work hour. The cost for required parts
would be approximately $865 per airplane. Additionally, once these
interim actions are accomplished, the cost impact of the terminating
modifications discussed previously would be reduced by $2,400 per
airplane.
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 93-NM-193-AD.
Applicability: Model F28 Mark 0100 series airplanes equipped
with Dowty Aerospace main landing gear (MLG) part number 201072011,
201072012, 201072013, 201072014, 201072015, or 201072016;
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 (g) 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 MLG wheel axle due to problems
associated with corrosion and cracking, accomplish the following:
(a) Within 30 days after the effective date of this AD, remove
the MLG wheels and brakes and perform a visual inspection to detect
corrosion and cracking in the wheel axles of the MLG sliding members
in accordance with Fokker Service Bulletin F100-32-079, Revision 1,
dated October 4, 1993, and paragraph 2.A. of the Accomplishment
Instructions of Dowty Aerospace Service Bulletin F100-32-63,
Revision 2, dated September 23, 1993.
(b) Following accomplishment of the inspection required by
paragraph (a) of this AD, accomplish either paragraph (b)(1) or
(b)(2) of this AD.
(1) Repeat the inspection required by paragraph (a) of this AD
thereafter at intervals not to exceed 3 months in accordance with
Fokker Service Bulletin SBF100-32-080, dated October 4, 1993, and
Dowty Aerospace Service Bulletin F100-32-64, Revision 1, dated
February 18, 1994, until the actions required by paragraph (e) of
this AD are accomplished. Or
(2) Accomplish paragraphs (b)(2)(i), (b)(2)(ii), and (b)(2)(iii)
of this AD at the times specified in those paragraphs in accordance
with Fokker Service Bulletin SBF100-32-083, dated March 23, 1994.
(i) Within 3 months after the accomplishment of an inspection
required by paragraph (a) or (b)(1) of this AD: Rework the axles in
accordance with Part 2 of the Accomplishment Instructions of the
service bulletin. Repeat this rework thereafter at intervals not to
exceed 12 months or 2,200 landings, whichever occurs first. And
(ii) Prior to or concurrent with accomplishing the initial
rework specified in paragraph (b)(2)(i) of this AD: Replace the main
wheel brake units in accordance with Part 1 of the Accomplishment
Instructions of the service bulletin. And
(iii) Within 3 months after the first accomplishment of the
rework required by paragraph (b)(2)(i) of this AD: Begin performing
interim inspections (``sampling program'') to detect corrosion and
cracking in the wheel axles of the MLG sliding members, in
accordance with Part 3 of the Accomplishment Instructions of the
service bulletin. Perform these inspections at the intervals
specified in the service bulletin until the actions required by
paragraph (e) of this AD are accomplished.
(c) If any corrosion is found during any inspection required by
this AD, prior to further flight, rework the affected area and
perform a non-destructive testing (NDT) inspection to detect cracks
in the MLG wheel axles, in accordance with Appendix A of Dowty
Aerospace Service Bulletin F100-32-63, Revision 2, dated September
23, 1993 (if corrosion is found during the initial inspection
required by this AD); or Dowty Aerospace Service Bulletin F100-32-
64, Revision 1, dated February 18, 1994 (if corrosion is found
during a repetitive inspection required by this AD); as applicable.
After rework, perform repetitive inspections of the affected area in
accordance with paragraph (b)(1) of this AD until the actions
required by paragraph (e) of this AD are accomplished.
(d) If any crack is found during any inspection required by this
AD, prior to further flight, replace the affected sliding member
with a serviceable sliding member in accordance with Dowty Aerospace
Service Bulletin F100-32-63, Revision 2, dated September 23, 1993
(if any crack is found during the initial inspection required by
this AD); or Dowty Aerospace Service Bulletin F100-32-64, Revision
1, dated February 18, 1994 (if any crack is found during a
repetitive inspection required by this AD); as applicable. After
replacement of the affected sliding member, perform the repetitive
inspections in accordance with paragraph (b)(1) of this AD until the
actions required by paragraph (e) of this AD are accomplished.
(e) At the next major gear overhaul, or within 4,400 landings
after accomplishment of the initial inspection required by paragraph
(a) of this AD, whichever occurs first: Rework the sliding member,
and replace the main wheel brake units in accordance
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with the Accomplishment Instructions of Fokker Service Bulletin
SBF100-32-081, dated March 23, 1994. Accomplishment of these actions
constitutes terminating action for the repetitive inspections and
the interim actions specified in paragraph (b) of this AD.
Note 2: Fokker Service Bulletin SBF100-32-081 references Dowty
Aerospace Service Bulletin F100-32-64, Revision 1, dated February
18, 1994, as an additional source of service information for
accomplishment of the rework and replacement.
(f) As of the effective date of this AD, no person shall install
a Dowty Aerospace MLG, part number 201072011, 201072012, 201072013,
201072014, 201072015, or 201072016, on any airplane unless the
requirements of this AD have been accomplished on that MLG.
Following its installation, the repetitive inspections required by
paragraph (b) of this AD shall be accomplished on that MLG.
(g) 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 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(h) 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 September 3, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-22920 Filed 9-6-96; 8:45 am]
BILLING CODE 4910-13-U