[Federal Register Volume 61, Number 212 (Thursday, October 31, 1996)]
[Proposed Rules]
[Pages 56170-56172]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-27924]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-NM-32-AD]
Airworthiness Directives; Fokker Model F27 Mark 050, 100, 200,
300, 400, 600, and 700 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 Mark 050,
100, 200, 300, 400, 600, and 700 series airplanes. This proposal would
require an ultrasonic inspection to determine if certain tubes are
installed in the drag stay units of the main landing gear (MLG), and
various follow-on actions. This proposal is prompted by a report that,
due to fatigue cracking from an improperly machined radius of the inner
tube, a drag stay broke, and, consequently, lead to the collapse of the
MLG during landing. The actions specified by the proposed AD are
intended to prevent such fatigue cracking, which could result in
reduced structural integrity or collapse of the MLG.
DATES: Comments must be received by December 10, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-32-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; and Dowty Aerospace, Customer Support
Center, P.O. Box 49, Sterling,
[[Page 56171]]
VA 20166. 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 96-NM-32-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-32-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 F27 Mark 050, 100, 200,
300, 400, 600, and 700 series airplanes. The RLD advises that it has
received a report that, due to a broken drag stay, the main landing
gear (MLG) on one airplane collapsed during landing. The broken drag
stay is attributed to fatigue cracking, which originated at a change in
the cross-section of the inner tube. The apparent cause of such fatigue
cracking has been attributed to an improperly machined radius of the
inner tube of the drag stay. Such fatigue cracking, if not detected and
corrected in a timely manner, could result in reduced structural
integrity or collapse of the MLG.
Explanation of Relevant Service Information
Fokker has issued Service Bulletin SBF50-32-029, dated February 11,
1994 (for Model F27 Mark 050 series airplanes) and Service Bulletin
F27/32-167, dated November 19, 1993 (for Model F27 Mark 100, 200, 300,
400, 600, and 700 series airplanes). These service bulletins describe
procedures for performing an ultrasonic inspection to determine if a
tube having part number (P/N) 200485300 with a straight bore, or a tube
having P/N 200259300 with a change in section (stepped bore), is
installed in the drag stay units (DSU) of the main landing gear (MLG).
They also describe procedures for various follow-on actions, including
re-identification of certain tubes, replacement of certain DSU's with
new/re-identified DSU's, and repetitive ultrasonic inspections of
certain DSU's. The RLD classified these service bulletins as mandatory
and issued Netherlands airworthiness directive BLA 93-169/2(A), dated
April 29, 1994, 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, the
proposed AD would require an ultrasonic inspection to determine if
certain tubes are installed on the DSU's of the MLG, and various
follow-on actions. The actions would be required to be accomplished in
accordance with the service bulletins described previously.
Cost Impact
The FAA estimates that 10 Model F27 Mark 050, 100, 200, 300, 400,
600, and 700 series airplanes of U.S. registry would be affected by
this proposed AD, that it would take approximately 2 work hours per
airplane to accomplish the proposed inspection, and that the average
labor rate is $60 per work hour. Based on these figures, the cost
impact of the inspection proposed by this AD on U.S. operators is
estimated to be $1,200, or $120 per airplane.
There currently are no Fokker Model F27 Mark 050 series airplanes
on the U.S. Register that would require the inspection of the DSU. The
only airplanes that would require this inspection are currently
operated by non-U.S. operators under foreign registry; therefore, they
are not directly affected by this AD action. However, the FAA considers
that inclusion of that requirement in this proposed rule is necessary
to ensure that the unsafe condition is addressed in the event that any
of these airplanes are imported and placed on the U.S. Register in the
future.
The 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
[[Page 56172]]
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-32-AD.
Applicability: Model F27 Mark 050, 100, 200, 300, 400, 600, and
700 series airplanes, equipped with Dowty Aerospace main landing
gear (MLG) drag stay units (DSU) having part number (P/N) 200684001,
200261001, or 200485001; certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
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 fatigue cracking in drag stay unit of the main
landing gear (MLG), which could result in reduced structural
integrity or collapse of the MLG, accomplish the following:
(a) Within 60 days after the effective date of this AD, perform
an ultrasonic inspection to determine if a tube having part number
(P/N) 200485300 with a straight bore, or a tube having P/N 200259300
with a change in section (stepped bore), is installed on the DSU's
of the MLG, in accordance with Fokker Service Bulletin F27/32-167,
dated November 19, 1993 (for Model F27 Mark 100, 200, 300, 400, 600,
and 700 series airplanes), or Fokker Service Bulletin SBF50-32-029,
dated February 11, 1994 (for Model F27 Mark 050 series airplanes),
as applicable.
Note 2: Fokker Service Bulletin F27/32-167 references Dowty
Service Bulletins 23-169B and 32-82W; and Fokker Service Bulletin
SBF50-32-029 references Dowty Service Bulletin F50-32-50; as
additional sources of service information for procedures to
accomplish the actions specified in this AD.
(b) For all airplanes: If any tube having P/N 200485300 with a
straight bore is found installed during the inspection required by
paragraph (a) of this AD, prior to further flight, reidentify it in
accordance with Fokker Service Bulletin F27/32-167, dated November
19, 1993 (for Model F27 Mark 100, 200, 300, 400, 600, and 700 series
airplanes); or Fokker Service Bulletin SBF50-32-029, dated February
11, 1994 (for Model F27 Mark 050 series airplanes); as applicable.
(c) For Model F27 Mark 50 series airplanes: If any tube having
P/N 200259300 with a change in section (stepped bore) is found
installed during the inspection required by paragraph (a) of this
AD, prior to further flight, replace the DSU with a new or
serviceable DSU having P/N 200684004, in accordance with Fokker
Service Bulletin SBF50-32-029, dated February 11, 1994.
(d) For F27 Mark 100, 200, 300, 400, 600, and 700 series
airplanes: If any tube having P/N 200259300 with a change in section
(stepped bore) is found installed during the inspection required by
paragraph (a) of this AD, prior to further flight, re-identify the
DSU in accordance with Fokker Service Bulletin F27/32-167, dated
November 19, 1993. Following accomplishment of the re-
identification, prior to further flight, perform an ultrasonic
inspection to detect cracks in the re-identified DSU's, in
accordance with that service bulletin.
(1) For airplanes equipped with any DSU re-identified as P/N
200684003, 200261003, or 200485003: If no crack is detected, no
further action is required by this AD.
(2) For airplanes equipped with any DSU re-identified as P/N
200684002, 200261002, or 200485002: If no crack is detected,
accomplish paragraph (c)(2)(i) and (c)(2)(ii) of this AD.
(i) Repeat the ultrasonic inspection required by paragraph (d)
of this AD thereafter at intervals not to exceed 1,500 flight
cycles.
(ii) At the next MLG overhaul, but no later than 12,000 flight
cycles after the effective date of this AD, rework and re-identify
the DSU again, or replace the DSU with a re-identified DSU, in
accordance with the service bulletin. Accomplishment of the rework
and re-identification, or replacement constitutes terminating action
for the repetitive inspection requirements of this AD.
(3) If any crack signal indication of any DSU tube is greater
than or equal to 80 percent, prior to further flight, replace the
DSU with a re-identified DSU, in accordance with the applicable
service bulletin.
(4) If any crack signal indication of any DSU tube is greater
than or equal to 1 percent but less than 80 percent, accomplish
paragraph (d)(4)(i) and (d)(4(ii) of this AD.
(i) Repeat the ultrasonic inspection required by paragraph (d)
of this AD thereafter at intervals not to exceed 1,500 flight
cycles.
(ii) At the next MLG overhaul, but no later than 12,000 flight
cycles after the effective date of this AD, replace the DSU with a
re-identified DSU, in accordance with the service bulletin.
Accomplishment of the replacement constitutes terminating action for
the repetitive inspection requirements of 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 24, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-27924 Filed 10-30-96; 8:45 am]
BILLING CODE 4910-13-U
