[Federal Register Volume 69, Number 47 (Wednesday, March 10, 2004)]
[Rules and Regulations]
[Pages 11299-11303]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-5069]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2003-NM-258-AD; Amendment 39-13516; AD 2004-05-21]
RIN 2120-AA64
Airworthiness Directives; Bombardier Model DHC-8-102, -103, -106,
-201, -202, -301, -311, and -315 Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to certain Bombardier airplanes as listed above. This
action requires lubrication of the flap actuators, repetitive
measurements (``checks'') of the backlash of the flap actuators,
determination of the next backlash measurement interval, and
replacement of discrepant actuators with new or overhauled actuators if
necessary. This action is necessary to prevent the mechanical
disconnection of a flap actuator, which, if followed by failure of the
flap panel's second actuator due to increased loading, could result in
flap asymmetry and consequent loss of controllability of the airplane.
This action is intended to address the identified unsafe condition.
DATES: Effective March 25, 2004.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 25, 2004.
Comments for inclusion in the Rules Docket must be received on or
before April 9, 2004.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 2003-NM-258-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9 a.m. and 3 p.m., Monday through Friday, except
Federal holidays. Comments may be submitted via fax to (425) 227-1232.
Comments may also be sent via the Internet using the following address:
[email protected]. Comments sent via the Internet must contain
``Docket No. 2003-NM-258-AD'' in the subject line and need not be
submitted in triplicate. Comments sent via fax or the Internet as
attached electronic files must be formatted in Microsoft Word 97 or
2000 or ASCII text.
The service information referenced in this AD may be obtained from
Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt
Boulevard, Downsview, Ontario M3K 1Y5, Canada. This information may be
examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue,
SW., Renton, Washington; or at the FAA, New York Aircraft Certification
Office, FAA, 1600 Stewart Avenue, suite 410, Westbury, New York; or at
the Office of the Federal Register, 800 North Capitol Street, NW.,
suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Ezra Sasson, Aerospace Engineer,
Systems and Flight Test Branch, ANE-172, New York Aircraft
Certification Office, FAA, 1600 Stewart Avenue, suite 410, Westbury,
New York 11590; telephone (516) 228-7320; fax (516) 794-5531.
SUPPLEMENTARY INFORMATION: Transport Canada Civil Aviation (TCCA),
which is the airworthiness authority for Canada, notified the FAA that
an unsafe condition may exist on certain Bombardier Model DHC-8-102, -
103,
[[Page 11300]]
-106, -201, -202, -301, -311, and -315 airplanes. TCCA advises that
field reports indicate that the ballscrew and nut assembly of the flap
drive actuators may wear to the extent that the ballscrew mechanically
disconnects from the ballnut. There have been four known incidents that
involved actuator disconnect. The mechanical disconnection of the
ballscrew from the ballnut can lead to binding of the flap system. If
both actuators of an extended flap panel disconnect, the affected panel
may be aerodynamically backdriven, resulting in asymmetric flaps. This
condition, if not corrected, could result in loss of controllability of
the airplane.
Maintenance Schedule
Analysis of new data indicates the need to reduce the current
interval specified in the Bombardier Model DHC-8 maintenance program
for measuring the backlash of the flap ballscrew actuators. Based on
the new data, the FAA and TCCA have determined that this interval must
be reduced from a ``2C'' check (currently a maximum of 10,000 flight
hours) to a variable interval (a maximum of 3,000 flight cycles) that
is based on each previous backlash measurement and actuator wear rate.
Explanation of Relevant Service Information
Bombardier has issued Alert Service Bulletin A8-27-98, dated
February 20, 2003, which describes procedures for measuring the
backlash of the flap actuators. The service bulletin also provides the
means to calculate each subsequent interval for repeating the backlash
measurement, based on the wear rate and previous backlash measurement.
If a certain backlash length is exceeded, the service bulletin
recommends replacing the actuator with a serviceable actuator before
further flight.
Bombardier has revised certain procedures for lubricating the flap
actuators, which are described in the temporary revisions (TRs) to the
de Havilland Dash-8 Maintenance Program Manual listed in the following
table:
de Havilland Maintenance Program Manual TRs
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Model PSM No. de Havilland TR No. Task No.
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DHC-8-102, -103, and -106 airplanes..... 1-8-7 MRB-143............................... 2750/04
DHC-8-201 and -202 airplanes............ 1-82-7 MRB 2-21.............................. 2750/04
DHC-8-301, -311, and -315 airplanes..... 1-83-7 MRB 3-152............................. 2750/04
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These TRs introduce procedures that incorporate use of new lubrication
tools and a particular grease that will improve lubrication of the flap
actuators and consequently reduce component wear.
Accomplishment of the actions specified in the service information
is intended to adequately address the identified unsafe condition. TCCA
mandated accomplishment of this service information and issued Canadian
airworthiness directive CF-2002-26R1, dated October 6, 2003, to ensure
the continued airworthiness of these airplanes in Canada.
FAA's Conclusions
These airplane models are manufactured in Canada and are 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, TCCA has kept the FAA informed of
the situation described above. The FAA has examined the findings of
TCCA, 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 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, this AD is being issued to prevent the mechanical
disconnection of a flap actuator, which, if followed by failure of the
panel's second actuator due to increased loading, could result in flap
asymmetry and consequent loss of controllability of the airplane. This
AD requires a one-time actuator lubrication, repetitive measurements
(``checks'') of the backlash of the flap actuators, determination of
each subsequent backlash check interval, and replacement of discrepant
actuators with new or overhauled actuators if necessary. The actions
are required to be accomplished in accordance with the service
information described previously. The compliance times for the initial
measurement range from 30 days to 3,000 total accumulated flight cycles
on the actuator, with each subsequent interval ranging from 45 to 3,000
flight cycles, depending on each previous measurement and the wear
rate. The FAA and TCCA agree on the following minor variations between
the airworthiness directives:
1. Part A., paragraph 1., of the TCCA airworthiness directive
mandates revising the TCCA-approved maintenance schedule by
incorporating the applicable flap actuator lubrication task specified
in the maintenance program manual TRs described previously. This (FAA)
AD requires a one-time lubrication, but the lubrication maintenance
schedule is not expressly required by this AD, because the lubrication
schedule itself does not address the unsafe condition identified in
this (FAA) AD. Rather, the lubrication schedule was established to
reduce wear and tear on the flap actuators (thereby extending actuator
life and decreasing costs).
2. Part A., paragraph 3., of the TCCA airworthiness directive
mandates a specific compliance time, task card, and lubrication tools
and grease for the lubrication. This (FAA) AD does not include these
requirements, which are specified in the task card as part of the
maintenance manual TRs (and specified in part A., paragraph 2., of the
TCCA airworthiness directive); operators are expected to comply with
the current, MRB-required task card. If an operator cannot comply with
this AD because the specific grease or tools are unavailable within the
required compliance time, the FAA may consider requests to extend the
compliance time, as provided by paragraph (f) of this AD, if data are
presented to justify such an extension.
3. The TCCA airworthiness directive mandates sending an inspection
report to Bombardier or the actuator manufacturer (Hamilton
Sundstrand). This (FAA) AD does not require such a report.
4. The TCAA airworthiness directive requires that certain actions
be done ``not later than during the next A-check.'' Paragraph (a)(2) of
this (FAA) AD identifies that interval as 500 flight
[[Page 11301]]
hours, which for all affected operators is the same as the A-check.
5. In this (FAA) AD, Notes 1 through 12 of the TCCA airworthiness
directive have been either excluded as redundant or incorporated as
guidance into the requirements.
Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All
communications received on or before the closing date for comments will
be considered, and this rule may be amended in light of the comments
received. Factual information that supports the commenter's ideas and
suggestions is extremely helpful in evaluating the effectiveness of the
AD action and determining whether additional rulemaking action would be
needed.
Submit comments using the following format:
Organize comments issue-by-issue. For example,
discuss a request to change the compliance time and a request to change
the service bulletin reference as two separate issues.
For each issue, state what specific change to
the AD is being requested.
Include justification (e.g., reasons or data)
for each request.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the 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 that
summarizes each FAA-public contact concerned with the substance of this
AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this rule must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 2003-NM-258-AD.'' The postcard will be date stamped
and returned to the commenter.
Regulatory Impact
The regulations adopted herein will not have a substantial direct
effect 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, it
is determined that this final rule does not have federalism
implications under Executive Order 13132.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and that it is not a ``significant regulatory
action'' under Executive Order 12866. It has been determined further
that this action involves an emergency regulation under DOT Regulatory
Policies and Procedures (44 FR 11034, February 26, 1979). If it is
determined that this emergency regulation otherwise would be
significant under DOT Regulatory Policies and Procedures, a final
regulatory evaluation will be prepared and placed in the Rules Docket.
A copy of it, if filed, 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
0
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends part 39 of
the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
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]
0
2. Section 39.13 is amended by adding the following new airworthiness
directive:
2004-05-21 Bombardier, Inc. (Formerly de Havilland, Inc.): Amendment
39-13516. Docket 2003-NM-258-AD.
Applicability: Model DHC-8-102, -103, -106, -201, -202, -301, -
311, and -315 airplanes; certificated in any category; serial
numbers 003 and subsequent; equipped with any flap actuator having
part number 734181, 734374, or 755216.
Compliance: Required as indicated, unless accomplished
previously.
To prevent the mechanical disconnection of a flap actuator,
which, if followed by failure of the flap panel's second actuator
due to increased loading, could result in flap asymmetry and
consequent loss of controllability of the airplane, accomplish the
following:
Actuator Lubrication
(a) Lubricate the flap actuators at the later of the times
specified in paragraphs (a)(1) and (a)(2) of this AD, in accordance
with the product support manuals (PSMs) and temporary revisions
(TRs) to the maintenance program manual listed in Table 1 of this
AD.
(1) Within 2,500 flight hours or 18 months after the most recent
flap actuator lubrication, whichever occurs first.
(2) Within 500 flight hours after the effective date of this AD.
Table 1.--de Havilland Maintenance Program Manual TRs
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TR PSM Task No.
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MRB-143................................. 1-8-7 2750/04
MRB 2-21................................ 1-82-7 2750/04
MRB 3-152............................... 1-83-7 2750/04
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Initial Backlash Measurement
(b) Table 2 of this AD identifies service information references
for the backlash measurement. Operators may have previously used one
of these references to measure the actuator backlash.
[[Page 11302]]
Table 2.--Backlash Measurement References
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Reference Date
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Bombardier Alert Service Bulletin October 31, 2001.
A8-27-95.
Bombardier Alert Service Bulletin April 17, 2002.
A8-27-95, Revision A.
Bombardier Alert Service Bulletin February 20, 2003.
A8-27-98.
DHC-8 Maintenance Task Card Manual, November 23, 2001, or later
Task No. 2750/18. revisions issued before the
effective date of this AD.
Transport Canada Airworthiness May 2, 2002.
Directive CF-2002-26.
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Measure the backlash of each actuator at the applicable time
specified in paragraph (b)(1) or (b)(2) of this AD, in accordance
with the Accomplishment Instructions of the applicable Hamilton
Sundstrand Service Bulletin 734181-27-A5 or 734374-27-A5, both of
which form part of Bombardier Alert Service Bulletin A8-27-98, dated
February 20, 2003.
(1) If the most recent backlash measurement has been done before
the effective date of this AD in accordance with a reference listed
in Table 2 of this AD: Do the applicable action specified in Table 3
of this AD.
Table 3.--Intervals: Backlash Measurement Done Previously
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If the measurement was-- Then--
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Do the initial measurement within the
later of:
(i) <= 0.027 inch............ 3,000 flight cycles since the most recent
measurement, or 90 days after the
effective date of this AD.
(ii) 0.027 inch The applicable interval specified in
and < 0.060 inch, and the Service Bulletin A8-27-98, or 90 days
wear rate is recorded or can after the effective date of this AD.
be calculated.
(iii) 0.027 inch The applicable interval, based on a wear
and < 0.060 inch, but the rate of 0.010 inch per 1,000 flight
wear rate is unknown or cycles, as specified in Service Bulletin
cannot be calculated due to A8-27-98, or 90 days after the effective
lack of data. date of this AD.
(iv) = 0.060 inch The applicable interval specified in
and < 0.070 inch, and the Service Bulletin A8-27-98, or 30 days
wear rate is recorded or can after the effective date of this AD.
be calculated.
(v) = 0.060 inch The applicable interval, based on a wear
and < 0.070 inch, but the rate of 0.010 inch per 1,000 flight
wear rate is unknown or cycles, as specified in Service Bulletin
cannot be calculated due to A8-27-98, or 30 days after the effective
lack of data. date of this AD.
(vi) < 0.050 inch, but not 1,000 flight cycles since the most recent
recorded. measurement, or 90 days after the
effective date of this AD.
(vii) = 0.070 inch Replace the flap actuator with a new or
overhauled part: Before further flight.
------------------------------------------------------------------------
(2) If no backlash measurement has been done as of the effective
date of this AD in accordance with a reference listed in Table 2 of
this AD: Do the next measurement at the applicable time specified in
Table 4 of this AD.
Table 4.--Intervals: No Prior Backlash Measurement
------------------------------------------------------------------------
If the actuator, since new or Then do the initial measurement
overhauled, has accumulated-- within--
------------------------------------------------------------------------
(i) <= 3,000 total flight cycles....... 3,000 total flight cycles since
new or overhauled, or within
180 days after the effective
date of this AD, whichever
occurs later.
(ii) 3,000 total flight 60 days after the effective
cycles. date of this AD.
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Determination of Subsequent Intervals
(c) After each actuator backlash measurement required by this
AD, determine (calculate) the next measurement interval by the
applicable time specified in Table 5 of this AD. To determine each
interval, use paragraph 2.A.(4)(b) and Figure 4 of the applicable
Hamilton Sundstrand Service Bulletin 734181-27-A5 or 734374-27-A5,
both of which form part of Bombardier Alert Service Bulletin A8-27-
98, dated February 20, 2003. Alternatively, the Bombardier
spreadsheet ``Dash 8 Q100/200/300 Flap Ballscrew Backlash Data, Data
Recording and Charting Utility,'' document number BM--DHI--RM--
APP01, may be used.
Table 5.--Timeframe To Determine Subsequent Intervals
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Determine (calculate) the next
For any recorded backlash that was-- interval--
------------------------------------------------------------------------
(1) = 0.060 inch and < 0.070 Within 45 flight cycles after
inch. the recorded completion of
backlash measurement.
(2) 0.027 inch and < 0.060 Within 30 days after the
inch. recorded completion of
backlash measurement.
(3) <= 0.027 inch...................... Within 3,000 flight cycles
after the recorded completion
of backlash measurement.
(4) Not done because the actuator was Before the accumulation of
new or newly overhauled. 3,000 total flight cycles on
the actuator.
------------------------------------------------------------------------
[[Page 11303]]
Subsequent Repetitive Measurements
(d) After the initial backlash measurement required by paragraph
(b) of this AD, repeat each subsequent measurement within the
applicable interval specified in paragraph (c) of this AD, in
accordance with paragraph 2.A.(1) of the applicable Hamilton
Sundstrand Service Bulletin 734181-27-A5 or 734374-27-A5, both of
which form part of Bombardier Alert Service Bulletin A8-27-98, dated
February 20, 2003.
Follow-on and Corrective Actions
(e) After each backlash measurement required by paragraph (b) or
(d) of this AD, do the actions required by paragraph (e)(1) or
(e)(2), as applicable, of this AD. Do the actions in accordance with
the Accomplishment Instructions of Bombardier Alert Service Bulletin
A8-27-98, dated February 20, 2003.
(1) For any measured backlash of less than 0.070 inch: Repeat
the measurement within the interval specified in paragraph (c) of
this AD.
(2) For any measured backlash of 0.070 inch or more: Replace the
actuator with a new or overhauled actuator before further flight.
Alternative Methods of Compliance
(f) In accordance with 14 CFR 39.19, the Manager, New York
Aircraft Certification Office (ACO), FAA, is authorized to approve
alternative methods of compliance for this AD.
Incorporation by Reference
(g) Unless otherwise specified in this AD, the actions must be
done in accordance with Bombardier Alert Service Bulletin A8-27-98,
dated February 20, 2003; and the de Havilland temporary revisions to
the applicable de Havilland Dash-8 Program Support Manuals listed in
Table 6 of this AD:
Table 6.--de Havilland Temporary Revisions
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Service information PSM Task No. Date
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Temporary Revision MRB-143.................... 1-8-7 2750/04......................... May 18, 2001.
Temporary Revision MRB 2-21................... 1-82-7 2750/04......................... May 18, 2001.
Temporary Revision MRB 3-152.................. 1-83-7 2750/04......................... May 18, 2001.
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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 Bombardier, Inc., Bombardier
Regional Aircraft Division, 123 Garratt Boulevard, Downsview,
Ontario M3K 1Y5, Canada. Copies may be inspected at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington; or at the FAA, New York Aircraft Certification Office,
FAA, 1600 Stewart Avenue, suite 410, Westbury, New York; or at the
Office of the Federal Register, 800 North Capitol Street, NW., suite
700, Washington, DC.
Note 1: The subject of this AD is addressed in Canadian
airworthiness directive CF-2002-26R1, dated October 6, 2003.
Effective Date
(h) This amendment becomes effective on March 25, 2004.
Issued in Renton, Washington, on March 1, 2004.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-5069 Filed 3-9-04; 8:45 am]
BILLING CODE 4910-13-P