[Federal Register Volume 61, Number 215 (Tuesday, November 5, 1996)]
[Proposed Rules]
[Pages 56925-56927]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-28323]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-94-AD]
Airworthiness Directives; Fokker Model F28 Mark 0100 and Mark
0070 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
and Mark 0070 series airplanes. This proposal would require
modification of the hook and latch engagement assemblies of the engine
cowl doors, measurement of the aerodynamic mismatch between the fixed
cowl and lower cowl door, and repair, if necessary. This proposal is
prompted by reports of operational experience that indicate that an
aerodynamic mismatch may exist between the fixed engine cowl and the
lower cowl door, and may be the result of one or more hooks of the
engagement assemblies not engaging adequately. This condition may cause
the other hooks to carry loads higher than they were originally
designed to carry, and could result in the failure of those hooks that
are engaged. The actions specified by the proposed AD are intended to
prevent possible separation of the lower cowling from the airplane due
to failure of the hooks of the engagement assemblies.
DATES: Comments must be received by December 16, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-94-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 95-NM-94-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. 95-NM-94-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 and Mark 0070
series airplanes. The RLD has received reports indicating that
operational experience has shown that an aerodynamic mismatch (gap) may
exist between the fixed engine cowl and the lower cowl door. The lower
cowl
[[Page 56926]]
door is engaged in the ``closed'' position by two latches and three
hooks. An excessive aerodynamic mismatch (or gap) in this assembly
indicates that one or more hooks are not engaged properly. If this is
the case, the aerodynamic mismatch could cause the hooks that are
engaged to carry loads higher than they were originally designed to
carry; in the event of a burst engine bypass duct, this situation could
result in failure of the hooks that are engaged. Failure of these hooks
could result in the lower engine cowling separating from the airplane
and subsequently causing damage to other airplane structure or posing a
hazard to persons on the ground.
Explanation of Relevant Service Information
Fokker has issued Service Bulletin SBF100-71-019, dated March 21,
1996, which describes procedures for:
1. modifying the hook and latch engagement assemblies of the left
and right engine lower cowl door; and
2. measuring the aerodynamic mismatch between the fixed cowl and
lower cowl.
If the measurement of the aerodynamic mismatch is beyond the limits
specified in the service bulletin, the service bulletin also provides
procedures to measure the mis-engagement between the left and right
engine hooks of the fixed cowl door and the clevis fittings of the
lower cowl door. The service bulletin also describes modification
procedures for the mid-clevis fitting on the right and left engine
lower cowl door if the mis-engagement is beyond the limits specified in
the service bulletin.
The RLD classified this service bulletin as mandatory and issued
Netherlands airworthiness directive BLA 1989-049/3 (A), dated June 28,
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 modification of the
hook and latch engagement assemblies of the left and right engine lower
cowl door. It would also require measurement of the aerodynamic
mismatch between the fixed cowl and lower cowl, and various follow-on
actions, dependent upon whether the measurement of the aerodynamic
mismatch is beyond certain limits. These actions would be required to
be accomplished in accordance with the service bulletin described
previously.
Cost Impact
The FAA estimates that 124 Fokker Model F28 Model 0100 and 0070
series airplanes of U.S. registry would be affected by this proposed
AD, that it would take approximately 3 work hours per airplane to
accomplish the initial inspection and modification, and that the
average labor rate is $60 per work hour. Based on these figures, the
total cost impact of the proposed AD on U.S. operators is estimated to
be $22,320, or $180 per airplane.
The total cost impact figure discussed above is 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. 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:
Fokker: Docket 95-NM-94-AD.
Applicability: Model F28 Mark 0100 and Mark 0070 series
airplanes as listed in Fokker Service Bulletin SBF100-71-019, dated
March 21, 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 (e) 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 separation of the lower cowling from the airplane due
to failure of the hook and latch engagement assembly of the cowl
door, accomplish the following:
(a) Accomplish the requirements of paragraph (b) of this AD at
the later of the times indicated in paragraph (a)(1), (a)(2), or
(a)(3) of this AD:
(1) prior to the accumulation of 2,500 total flight cycles; or
(2) within 2,500 flight cycles since the last inspection
performed in accordance with Fokker Service Bulletin SBF100-71-003,
dated April 14, 1989; Revision 1, dated August 8, 1989, or Revision
2, dated November 21, 1994; or
(3) within 30 days after the effective date of this AD.
[[Page 56927]]
(b) At the time specified in paragraph (a) of this AD,
accomplish the actions specified in either paragraph (b)(1) or
(b)(2) of this AD, as applicable:
(1) For airplanes specified in Part 1 of Fokker Service Bulletin
SBF100-71-019, dated March 21, 1996: Modify the hook and latch
engagement assemblies of the left and right engine cowl doors, and
inspect to determine the aerodynamic mismatch between the fixed cowl
and lower cowl door; in accordance with Part 1 of the Accomplishment
Instructions of Fokker Service Bulletin SBF100-71-019, dated March
21, 1996.
Note 2: Accomplishment of the modification of the hook and latch
engagement assemblies of the left and right engine cowl doors, in
accordance with Part 1 of the Accomplishment Instructions of Fokker
Service Bulletin SBF100-71-003, dated April 14, 1989; Revision 1,
dated August 8, 1989; or Revision 2, dated November 21, 1994; is
considered acceptable for compliance with the applicable
modification specified in paragraph (b)(1) of this amendment.
(2) For airplanes specified in Part 2 of Fokker Service Bulletin
SBF100-71-019, dated March 21, 1996, excluding those airplanes
subject to paragraph (b)(1) of this AD: Perform a one-time
inspection to determine the aerodynamic mismatch between the fixed
cowl and the lower cowl door, in accordance with Part 2 of the
Accomplishment Instructions of Fokker Service Bulletin SBF100-71-
019, dated March 21, 1996.
(c) If the aerodynamic mismatch measured between the fixed cowl
and lower cowl door is less than or equal to 4.5 mm, no further
action is required by this AD.
(d) If the aerodynamic mismatch measured between the fixed cowl
and lower cowl door is greater than 4.5 mm, prior to further flight,
perform a one-time inspection to measure the mis-engagement between
the left and right engine hooks of the fixed cowl door and the
clevis fittings of the lower cowl door; in accordance with Part 2 of
the Accomplishment Instructions of Fokker Service Bulletin SBF100-
71-019, dated March 21, 1996.
(1) If the mis-engagement is less than or equal to 6.5 mm, no
further action is required by this AD.
(2) If the mis-engagement is greater than 6.5 mm: Within 1 year
after measuring the mis-engagement required by this paragraph,
modify the mid-clevis fitting on the right and left engine lower
cowl door; in accordance with Part 3 of the Accomplishment
Instructions of Fokker Service Bulletin SBF100-71-019, dated March
21, 1996. After accomplishment of this modification, no further
action is required by this AD.
(e) 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.
(f) 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 October 29, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-28323 Filed 11-4-96; 8:45 am]
BILLING CODE 4910-13-P
