[Federal Register Volume 64, Number 207 (Wednesday, October 27, 1999)]
[Proposed Rules]
[Pages 57808-57810]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-28086]
[[Page 57808]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-298-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737, 757, and 767 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 Boeing Model 737, 757, and
767 series airplanes. This proposal would require repetitive
inspections of certain motor operated hydraulic shutoff valves to
detect malfunctioning; and replacement with new valves, if necessary.
This proposal also would require eventual replacement of certain
existing valves with new valves, which would constitute terminating
action for the repetitive inspections. This proposal is prompted by
reports that the motor switch contacts on certain hydraulic shutoff
valves were misaligned, causing subsequent malfunction of those valves.
The actions specified by the proposed AD are intended to prevent
failure of the motor operated hydraulic shutoff valves, which could
result in leakage of hydraulic fluid to the engine fire zone, reduced
ability to retract the landing gear, loss of backup electrical power or
other combinations of failures; and consequent reduced controllability
of the airplane.
DATES: Comments must be received by December 13, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-298-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: 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 98055-4056; telephone (425) 227-2673; 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 statement is made: ``Comments
to Docket Number 98-NM-298-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. 98-NM-298-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA received reports indicating that functional testing of the
motors of certain hydraulic shutoff valves of Boeing Model 737, 757,
and 767 series airplanes revealed that the motor switch contacts on the
valves were misaligned. This misalignment could prevent the valve motor
from turning off after it reaches the commanded stop position at the
end of switch travel; such misalignment has been attributed to a design
flaw. If the motor ceases operation and cannot be recommanded to
operate, the related valve cannot open and close for the affected
hydraulic system. Such malfunction could result in failure of the
valve, leakage of hydraulic fluid to the engine fire zone, reduced
ability to retract the landing gear, loss of backup electrical power,
or other combinations of failures; and consequent reduced
controllability of the airplane.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletins
737-29A1073, Revision 2, (for Model 737 series airplanes); 757-29A0048,
Revision 2, (for Model 757 series airplanes), both dated July 1, 1999;
and 767-29A0083, Revision 2, dated July 15, 1999 (for Model 767 series
airplanes). These service bulletins describe procedures for repetitive
inspections of the motor operated hydraulic shutoff valves to verify
proper functioning. The service bulletins also describe procedures for
replacement of any malfunctioning valves with new valves.
Accomplishment of the actions specified in the alert service bulletins
is intended to adequately address the identified unsafe condition.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other products of this same type design, the
proposed AD would require accomplishment of the actions specified in
the alert service bulletins described previously, except as discussed
below.
Differences Between the Alert Service Bulletins and the Proposed AD
Operators should note that this AD proposes to mandate, within 2
years, the replacement of the motor operated hydraulic shutoff valves
described in the alert service bulletins as terminating action for the
repetitive inspections. The FAA has determined that long-term continued
operational safety will be better assured by design changes to remove
the source of the problem, rather than by repetitive inspections. Long-
term inspections may not be providing the degree of safety assurance
necessary for the transport airplane fleet. This, coupled with a better
understanding of the human factors associated with numerous continual
inspections, has led the FAA to consider placing less emphasis on
inspections and more emphasis on design improvements. The proposed
replacement requirement is in consonance with these conditions.
Operators should further note that the Circle Seal motor operated
hydraulic shutoff valves having the replacement
[[Page 57809]]
part numbers (P/N) specified in the alert service bulletins are not
adequate for installation as replacement parts due to intermittent
failures in the valves. The failures prevent the valves from being
moved to the commanded position when commanded to open or close.
However, Circle Seal valves having P/N S270T010-10, S270T010-11, and
S270T010-12 are adequate for installation as replacement parts.
The FAA has approved design changes incorporated into these valves,
and the valves are being installed on airplanes in production.
Cost Impact
There are approximately 3,029 Boeing Model 737 series airplanes of
the affected design in the worldwide fleet. The FAA estimates that
1,234 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, at an average labor rate of $60 per
work hour. Based on these figures, the cost impact of the proposed AD
on U.S. operators is estimated to be $148,080, or $120 per airplane,
per inspection cycle.
There are approximately 802 Boeing Model 757 series airplanes of
the affected design in the worldwide fleet. The FAA estimates that 558
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
proposed inspection, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of the proposed AD on U.S.
operators is estimated to be $100,440, or $180 per airplane, per
inspection cycle.
There are approximately 701 Boeing Model 767 series airplanes of
the affected design in the worldwide fleet. The FAA estimates that 280
airplanes of U.S. registry would be affected by this proposed AD, that
it would take approximately 4 work hours per airplane to accomplish the
proposed inspection, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of the proposed AD on U.S.
operators is estimated to be $67,200, or $240 per airplane, per
inspection cycle.
For all airplanes, it would take approximately 5 work hours per
valve to accomplish the proposed replacement, at an average labor rate
of $60 per work hour.
Required parts and hydraulic fluid would cost approximately $4,316
per airplane. Based on these figures, the cost impact of the valve
replacements proposed by this AD on U.S. operators is estimated to be
$4,616 per airplane, per valve replacement. This proposed AD would
require eventual replacement of approximately 5,000 valves.
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 adding the following new
airworthiness directive:
Boeing: Docket 98-NM-298-AD.
Applicability: Model 737, 757, and 767 series airplanes,
certificated in any category, as listed in the following Boeing
Alert Service Bulletins:
737-29A1073, Revision 2, dated July 1, 1999 (for Model 737
series airplanes);
757-29A0048, Revision 2, dated July 1, 1999 (for Model 757
series airplanes);
767-29A0083, Revision 2, dated July 15, 1999 (for Model 767
series airplanes).
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 (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 failure of the motor operated hydraulic shutoff
valves, which could result in leakage of hydraulic fluid to the
engine fire zone, reduced ability to retract the landing gear, loss
of backup electrical power or other combinations of failures, and
consequent reduced controllability of the airplane, accomplish the
following:
Repetitive Inspections/Corrective Action
(a) Within 6 months after the effective date of this AD: Perform
a general visual inspection to detect malfunctioning of any Circle
Seal motor operated hydraulic shutoff valve having a part number
specified in the ``Existing Part Number'' column (including parts
marked with the suffix ``R'' after the serial number), of Paragraph
2.E. of Boeing Alert Service Bulletin 737-29A1073, Revision 2 (for
Model 737 series airplanes), or 757-29A0048, Revision 2 (for Model
757 series airplanes), both dated July 1, 1999; or 767-29A0083,
Revision 2, dated July 15, 1999 (for Model 767 series airplanes); as
applicable; in accordance with the applicable alert service
bulletin.
Note 2: For the purposes of this AD, a general visual inspection
is defined as: ``A visual examination of an interior or exterior
area, installation, or assembly to detect obvious damage, failure,
or irregularity. This level of inspection is made under normally
available lighting conditions such as daylight, hangar lighting,
flashlight, or drop-light and may require removal or opening of
access panels or doors. Stands, ladders, or platforms may be
required to gain proximity to the area being checked.''
(1) If any malfunction of any valve is detected, prior to
further flight, replace the valve with a new Whittaker valve in
accordance with the applicable service bulletin; or replace any
valve having P/N S270T010-1, -4, or -7, with a new Circle Seal valve
having P/N S270T010-10; replace any valve having P/N S270T010-2, -5,
or -8,
[[Page 57810]]
with a new Circle Seal valve having P/N S270T010-11; and replace any
valve having P/N S270T010-3, -6, or -9, with a new Circle Seal valve
having P/N S270T010-12; as applicable. Repeat the inspection
thereafter at intervals not to exceed 6 months until accomplishment
of the terminating action required by paragraph (b) of this AD.
(2) If no malfunction of any valve is detected, repeat the
inspection thereafter at intervals not to exceed 6 months until
accomplishment of the terminating action required by paragraph (b)
of this AD.
Terminating Action
(b) Within 2 years after the effective date of this AD,
accomplish the replacement of any Circle Seal valve having a P/N
specified in the ``Existing Part Number'' column (including parts
marked with the suffix ``R'' after the serial number), of Paragraph
2.E. of Boeing Alert Service Bulletin 737-29A1073, Revision 2 (for
Model 737 series airplanes); 757-29A0048, Revision 2 (for Model 757
series airplanes), both dated July 1, 1999; or 767-29A0083, Revision
2, dated July 15, 1999 (for Model 767 series airplanes); as required
by either paragraph (b)(1) or (b)(2) of this AD; in accordance with
the applicable service bulletin. Accomplishment of this replacement
constitutes terminating action for the repetitive inspections
required by this AD.
(1) Replace with a new Whittaker valve in accordance with the
applicable service bulletin.
(2) Replace any valve having P/N S270T010-1, -4, or -7, with a
new Circle Seal valve having P/N S270T010-10; replace any valve
having P/N S270T010-2, -5, or -8, with a new Circle Seal valve
having P/N S270T010-11; and replace any valve having P/N S270T010-3,
-6, or -9, with a new Circle Seal valve having P/N S270T010-12.
Spares
(c) As of the effective date of this AD, no person shall install
on any airplane, any part identified in the ``Existing Part Number''
column (including parts marked with the suffix ``R'' after the
serial number), of Paragraph 2.E. of Boeing Alert Service Bulletin
737-29A1073, Revision 2 (for Model 737 series airplanes); 757-
29A0048, Revision 2 (for Model 757 series airplanes), both dated
July 1, 1999; or 767-29A0083, Revision 2, dated July 15, 1999 (for
Model 767 series airplanes); as applicable.
Alternative Methods of Compliance
(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 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.
Note 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
Special Flight Permits
(e) Special flight permits may be issued in accordance with
Secs. 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 21, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-28086 Filed 10-26-99; 8:45 am]
BILLING CODE 4910-13-U
