[Federal Register Volume 64, Number 79 (Monday, April 26, 1999)]
[Proposed Rules]
[Pages 20226-20229]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-10346]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-133-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-100, -200, -300, -400,
and -500 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directive (AD), which would have superseded an existing AD that is
applicable to certain Boeing Model 737-100, -200, -300, -400, and -500
series airplanes. The existing AD currently requires an inspection of
reworked aileron/elevator power control units (PCU's) and rudder PCU's
to determine if reworked PCU manifold cylinder bores containing chrome
plating are installed, and replacement of the cylinder bores with bores
that have been reworked using the oversize method or the steel sleeve
method, if necessary. This action, among other items, revises the
previously proposed rule by expanding the applicability of the existing
AD to include airplanes equipped with certain rudder PCU's. The actions
specified by this new proposed AD are intended to prevent a reduced
rate of movement of the elevator, aileron, or rudder due to
contamination of hydraulic fluid from chrome plating chips; such
reduced rate of movement, if not corrected, could result in reduced
controllability of the airplane.
DATES: Comments must be received by May 21, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 97-NM-133-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 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.
FOR FURTHER INFORMATION CONTACT: Don Kurle, Senior Engineer, Systems
and Equipment Branch, ANM-130S, FAA, Transport Airplane Directorate,
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-2798; fax (425) 227-1181.
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
[[Page 20227]]
statement is made: ``Comments to Docket Number 97-NM-133-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-114, Attention: Rules
Docket No. 97-NM-133-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 Boeing Model 737-100, -200, -300, -400, and -500 series
airplanes, was published as a notice of proposed rulemaking (NPRM) in
the Federal Register on February 19, 1998 (63 FR 8369). That NPRM would
have superseded AD 97-09-14, amendment 39-10010 (62 FR 24008, May 2,
1997), to continue to require an inspection of reworked aileron/
elevator power control units (PCU's) and rudder PCU's to determine if
reworked PCU manifold cylinder bores containing chrome plating are
installed, and replacement of the cylinder bores with bores that have
been reworked using the oversize method or the steel sleeve method, if
necessary. That NPRM would have expanded the applicability of the
existing AD to include airplanes equipped with rudder PCU's having part
number (P/N) 65C37052-(). That NPRM also would have revised the
existing AD to exclude rudder PCU's (in addition to aileron/elevator
actuators) having serial numbers that contain ``ss'' from the
requirements of the proposed AD. That NPRM was prompted by a review of
the design of the flight control systems on Model 737 series airplanes.
The actions specified in that NPRM were intended to prevent a reduced
rate of movement of the elevator, aileron, or rudder due to
contamination of hydraulic fluid from chrome plating chips; such
reduced rate of movement, if not corrected, could result in reduced
controllability of the airplane.
Actions Since Issuance of Previous Proposal
Due consideration has been given to the comments received in
response to the NPRM.
Two commenters support the proposed rule.
Requests To Add a Certain Rudder PCU to the Requirements of the
Proposed AD
Several commenters state that rudder PCU's having P/N 65C37053-( )
are subject to the identified unsafe condition, and therefore, should
be included in the applicability statement and paragraphs (d) and (f)
of the proposed AD. The commenters note that AD 97-14-04, amendment 39-
10061 (62 FR 35068, June 30, 1997), requires replacement of rudder
PCU's having P/N 65C37052-( ) with PCU's having P/N 65C37053-( ). The
commenters point out that PCU's having P/N 65C37053-( ) are upgraded
from the same base PCU as the PCU's having P/N 65C37052-( ). The FAA
concurs. The FAA inadvertently omitted PCU, P/N 65C37053-( ), from the
requirements of the proposed AD. Therefore, the FAA has revised the
applicability statement and paragraphs (d) and (f) of the supplemental
NPRM accordingly.
Request To Allow Replacement With New Manifolds
One commenter requests that the FAA revise paragraphs (b) and (e)
of the proposed AD to allow PCU manifolds containing chrome plated
cylinder bores to be replaced with new manifolds, in addition to bores
that have been reworked using the oversize method or the steel method.
The commenter states that the original equipment manufacturer has not
produced PCU manifolds with chrome plated cylinder bores since 1985.
The FAA concurs. The FAA has confirmed with Boeing that manifolds with
chrome plated bores have not been produced since 1985. Therefore, the
FAA has revised the requirements of paragraphs (b) and (e) of the
supplemental NPRM to include an option of replacing the cylinder bores
containing chrome plating with PCU manifold cylinder bores that were
manufactured after December 31, 1985, in lieu of replacing the cylinder
bores that have been reworked using the oversize method or steel sleeve
method. In addition, the proposed requirements of those paragraphs have
been revised to allow operators to replace the rudder, aileron, or
elevator PCU with a certain PCU, as applicable.
Request To Delete Reference to Incorrect Service Letter
One commenter requests that the sentence ``accomplish the
replacement in accordance with the service letter'' be deleted from
paragraphs (b) and (e) of the proposed AD. The commenter states the
Boeing Service Letter 737-SL-27-30, dated April 1, 1985, does not
contain any replacement instructions. The commenter contends that the
service letter recommends the removal of the chrome bores and advises
of alternative repair methods.
The FAA concurs partially. The FAA acknowledges that the subject
service letter does not contain replacement procedures for
accomplishment of the requirements of paragraphs (b) and (e) of the AD.
The FAA has consulted with Boeing and determined that the following
chapters of the Boeing 737 Airplane Maintenance Manual (AMM) contain
the appropriate procedures for accomplishment of the actions specified
in paragraphs (b) and (e) of this AD:
Chapter 27-11-71 (for Model 737-100, -200, -300, -400, and
-500 series airplanes) for replacement of the aileron PCU;
Chapter 27-31-101 (for Model 737-100 and -200 series
airplanes), and Chapter 27-31-14 (for Model 737-300, -400, and -500
series airplanes) for replacement of the elevator PCU; and
Chapter 27-21-91 (for Model 737-100, -200, -300, -400, and
-500 series airplanes) for replacement of the rudder PCU.
Therefore, the FAA has revised paragraphs (b) and (e) of the
supplemental NPRM to reference these chapters of the AMM as the
appropriate sources of service information for accomplishment of the
actions specified in paragraphs (b)(1), (b)(2), (b)(3), (e)(1), and
(e)(2), as applicable.
Requests To Accept Previously Approved Alternative Method of
Compliance (AMOC)
Two commenters request that the inspection method specified in
Boeing Service Letter 737-SL-27-120, dated January 28, 1998, be
considered acceptable for compliance with the inspection requirements
of paragraphs (a) and (d) of the proposed AD. One of these commenters
states that the FAA approved this inspection method as an AMOC in
accordance with AD 97-09-14. The other commenter states that the
subject inspection method can be accomplished without removing the
PCU's from the airplanes and disassembling them. The FAA concurs with
the commenters' request. The FAA has added a new paragraph (g)(2) to
the supplemental NPRM to include a statement that reflects this point.
Conclusion
Since some of 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
There are approximately 2,675 Model 737 series airplanes of the
affected design in the worldwide fleet. The FAA
[[Page 20228]]
estimates that 1,091 airplanes of U.S. registry would be affected by
this proposed AD.
The actions that are currently required by AD 97-09-14, and
retained in this proposed AD, take approximately 5 work hours per
airplane to accomplish, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of the currently required
actions on U.S. operators is estimated to be $327,300, or $300 per
airplane.
The new actions that are proposed in this AD action would take
approximately 5 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the cost
impact of the proposed requirements of this AD on U.S. operators is
estimated to be $300 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 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. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-10010 (62 FR
24008, May 2, 1997), and by adding a new airworthiness directive (AD),
to read as follows:
Boeing: Docket 97-NM-133-AD. Supersedes AD 97-09-14, Amendment 39-
10010.
Applicability: Model 737-100, -200, -300, -400, and -500 series
airplanes, certificated in any category; equipped with the following
power control units (PCU):
a rudder PCU, having part number (P/N) 65-44861-( ), P/
N 65C37052-( ), or P/N 65C37053-( ) (except those having serial
numbers that contain ``ss''), and a serial number less than 1252A;
or
an aileron or elevator PCU having P/N 65-44761-( )
(except those having serial numbers that contain an ``ss'') and a
serial number less than 5360A.
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 (g)(1)
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 a reduced rate of movement of the elevator, aileron,
or rudder, which, if not corrected, could result in reduced
controllability of the airplane, accomplish the following:
(a) Perform an inspection of reworked or overhauled aileron and
elevator PCU's having P/N 65-44761-( ) (except those having serial
numbers that contain an ``ss''), and a serial number less than
5360A; and rudder PCU's having P/N 65-44861-( ) and a serial number
less than 1252A (except those having serial numbers that contain
``ss''); to determine if reworked PCU manifold cylinder bores
containing chrome plating are installed, in accordance with Boeing
Service Letter 737-SL-27-30, dated April 1, 1985. Accomplish the
inspection at the earlier of the times specified in paragraphs
(a)(1) and (a)(2) of this AD.
(1) Within 5 years or 15,000 flight hours after June 6, 1997
(the effective date of AD 97-09-14, amendment 39-10010), whichever
occurs first.
(2) At the next time the PCU is sent to a repair facility.
(b) If any reworked PCU manifold cylinder bores containing
chrome plating are found to be installed during the inspection
required by paragraph (a) of this AD: Prior to further flight,
accomplish the actions specified in paragraph (b)(1), (b)(2), or
(b)(3) of this AD in accordance with Chapter 27-11-71 (for Model
737-100, -200, -300, -400, and -500 series airplanes), Chapter 27-
31-101 (for Model 737-100 and -200 series airplanes), or Chapter 27-
31-14 (for Model 737-300, -400, and -500 series airplanes) of Boeing
737 Airplane Maintenance Manual (AMM); as applicable.
(1) Replace the cylinder bores with bores that were manufactured
after December 31, 1985, or with bores that have been reworked using
the oversize method or the steel sleeve method specified in Boeing
Service Letter 737-SL-27-30, dated April 1, 1985.
(2) Replace the aileron or elevator PCU with a PCU containing
the letters ``ss'' in its serial number or with a PCU having a
serial number of 5306A or higher.
(3) Replace the rudder PCU with a PCU containing the letters
``ss'' in its serial number or with a PCU having a serial number of
1252A or higher.
(c) As of June 6, 1997, no person shall install a reworked PCU
manifold cylinder bore containing chrome plating on an aileron or
elevator PCU having P/N 65-44761-( ), or on a rudder PCU having P/N
65-44861-( ), on any airplane unless the cylinder bore has been
reworked using the oversize method or the steel sleeve method
specified in Boeing Service Letter 737-SL-27-30, dated April 1,
1985.
(d) Perform an inspection of reworked or overhauled rudder PCU's
having P/N 65C37052-( ) or P/N 65C37053-( ) and a serial number less
than 1252A (except those having serial numbers that contain ``ss'')
to determine if reworked PCU manifold cylinder bores containing
chrome plating are installed, in accordance with Boeing Service
Letter 737-SL-27-30, dated April 1, 1985. Accomplish the inspection
at the earlier of the times specified in paragraphs (d)(1) and
(d)(2) of this AD.
(1) Within 5 years or 15,000 flight hours after the effective
date of this AD, whichever occurs first.
(2) At the next time the PCU is sent to a repair facility.
(e) If any reworked PCU manifold cylinder bores containing
chrome plating are found to be installed during the inspection
required by paragraph (d) of this AD: Prior to further flight,
accomplish the actions specified in paragraph (e)(1) or (e)(2) of
this AD in accordance with Chapter 27-21-91 (for Model 737-100, -
200, -300, -400, and -500 series airplanes) of Boeing 737 Airplane
Maintenance Manual (AMM).
(1) Replace the cylinder bores with bores that were manufactured
after December 31, 1985, or with bores that have been reworked using
the oversize method or the steel sleeve method specified in Boeing
Service Letter 737-SL-27-30, dated April 1, 1985.
(2) Replace the rudder PCU with a PCU containing the letters
``ss'' in its serial
[[Page 20229]]
number or with a PCU having a serial number of 1252A or higher.
(f) As of the effective date of this AD, no person shall install
a reworked PCU manifold cylinder bore containing chrome plating on a
rudder PCU having P/N 65C37052-( ) or
P/N 65C37053-( ) on any airplane unless the cylinder bore has been
reworked using the oversize method or the steel sleeve method
specified in Boeing Service Letter 737-SL-27-30, dated April 1,
1985.
(g)(1) 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 Aircraft Certification
Office (ACO), 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, Seattle ACO.
(g)(2) Alternative methods of compliance, approved previously in
accordance with AD 97-09-14, amendment 39-10010, are approved as
alternative methods of compliance with this AD.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(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 April 20, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-10346 Filed 4-23-99; 8:45 am]
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