[Federal Register Volume 62, Number 42 (Tuesday, March 4, 1997)]
[Rules and Regulations]
[Pages 9679-9680]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-5159]
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Rules and Regulations
Federal Register
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Federal Register / Vol. 62, No. 42 / Tuesday, March 4, 1997 / Rules
and Regulations
[[Page 9679]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-26-AD; Amendment 39-9954; AD 97-05-10]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737 Series 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 all Boeing Model 737 series airplanes. This action
requires removal of the main rudder power control unit (PCU) and
replacement with a serviceable unit. This amendment is prompted by a
report of the installation of an incorrect bolt on the main rudder PCU.
The actions specified in this AD are intended to prevent cracking of
the bearing of the main rudder PCU due to installation of an incorrect
bolt; such cracking could result in seizure of the bearing and
resultant uncommanded rudder movement.
DATES: Effective March 19, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 19, 1997.
Comments for inclusion in the Rules Docket must be received on or
before May 5, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 97-NM-26-AD, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056.
The service information referenced in this AD may be obtained from
Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington
98124-2207. This information may be examined 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.
FOR FURTHER INFORMATION CONTACT: Kenneth W. Frey, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue,
SW., Renton, Washington; telephone (206) 227-2673; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: The FAA has received a report of cracking of
the internal summing lever assembly bearing of the main rudder power
control unit (PCU) on a Model 737 series airplane. Investigation
revealed that a Hi-Lock bolt had been installed in the lever assembly
bearing instead of the correct bolt, Boeing Part Number (P/N) 66-22749-
1. Apparently, installation of the incorrect bolt was approved by the
repair station performing the installation. The Hi-Lock bolt has a
larger radius in the shoulder-to-shank transition than the correct
bolt. The larger bolt radius created an interference fit that caused
the inner race of the bearing to crack. Such cracking, if not detected
and corrected, could cause the bearing to seize and, consequently, lead
to an uncommanded rudder movement.
Explanation of Relevant Service Information
The FAA has reviewed Boeing Service Letter, 737-SL-27-112-B, dated
February 6, 1997, which lists serial numbers of certain PCU's of the
main rudder that have been identified as those having incorrect bolts.
The service letter describes procedures for removal of those PCU's from
the airplanes, and a one-time visual inspection to detect cracking of
the lever assembly bearing with a 10-power magnification and strong
light, a one-time eddy current inspection, and repair, if necessary,
before the PCU can be reinstalled on the airplane.
Explanation of the Requirements of the Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other Boeing Model 737 series airplanes of the same
type design, this AD is being issued to prevent cracking of the bearing
of the main rudder power control unit (PCU) due to the installation of
an incorrect bolt; such cracking could result in seizure of the bearing
and a consequent uncommanded rudder movement. This AD requires removal
of the PCU and replacement with a serviceable unit. This AD also
prohibits installation of a subject PCU on any airplane in the future
unless the PCU has been inspected (visually and by eddy current) to
detect cracking, repaired (if necessary), and tested. The actions are
required to be accomplished in accordance with the service letter
described previously.
This AD also requires that operators submit a report to the FAA of
the inspection results whenever a PCU is inspected for cracking.
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.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to
[[Page 9680]]
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 97-NM-26-AD.'' The postcard will be date stamped and
returned to the commenter.
Regulatory Impact
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.
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
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
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:
97-05-10 Boeing: Amendment 39-9954. Docket 97-NM-26-AD.
Applicability: Model 737 series airplanes, having a main rudder
power control unit (PCU) that is identified in Boeing Service Letter
737-SL-27-112-B, dated February 6, 1997; 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 (d) 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 cracking and seizing of the internal summing lever
assembly bearing of the main rudder power control unit (PCU), which
could result in uncommanded rudder movement, accomplish the
following:
(a) Within 90 days after the effective date of this AD, remove
the main rudder PCU and replace it with a serviceable unit in
accordance with Boeing Service Letter 737-SL-27-112-B, dated
February 6, 1997.
(b) As of 90 days after the effective date of this AD, no person
shall install on any airplane a main rudder PCU having a serial
number specified in Boeing Service Letter 737-SL-27-112-B, dated
February 6, 1997, unless the following actions have been
accomplished in accordance with Boeing Service Letter 737-SL-27-112-
B, dated February 6, 1997.
(1) Remove the internal summing lever assembly of the main
rudder PCU in accordance with the service letter.
(2) Perform a one-time visual inspection using 10-power
magnification and strong light to detect cracking of the bearing, in
accordance with the service letter.
(i) If no cracking is detected during the visual inspection,
perform an eddy current inspection to detect cracking of the bearing
in accordance with the service letter.
(A) If no cracking is detected during the eddy current
inspection, the unit may be reinstalled on the airplane after it is
reassembled and tested in accordance with the service letter.
(B) If any cracking is detected during the eddy current
inspection, before reinstallation of the PCU on any airplane, repair
the lever assembly, reassemble, and test; in accordance with the
service letter.
(ii) If any cracking is detected during the visual inspection,
before reinstallation of the PCU on any airplane, repair the lever
assembly, reassemble, and test, in accordance with the service
letter.
(c) Within 14 days after accomplishing the requirements of
paragraph (b) of this AD, submit a report of any cracked PCU bearing
to the Manager, Seattle Aircraft Certification Office (ACO), FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, WA
98055-4056; fax (206) 227-1181. The report shall include the
information specified in paragraphs (c)(1) and (c)(2) of this AD.
Information collection requirements contained in this regulation
have been approved by the Office of Management and Budget (OMB)
under the provisions of the Paperwork Reduction Act of 1980 (44
U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-
0056.
(1) The PCU part number and serial number.
(2) The date of the inspection and the inspection findings.
(d) 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, Seattle ACO. Operators shall submit
their requests through an appropriate FAA Principal Maintenance
Inspector, who may add comments and then send it to the Manager,
Seattle ACO.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(e) 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.
(f) The actions shall be done in accordance with Boeing Service
Letter 737-SL-27-112-B, dated February 6, 1997. 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 Boeing Commercial Airplane Group, P.O. Box 3707,
Seattle, Washington 98124-2207. 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.
(g) This amendment becomes effective on March 19, 1997.
Issued in Renton, Washington, on February 25, 1997.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-5159 Filed 2-28-97; 12:40 pm]
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