[Federal Register Volume 61, Number 184 (Friday, September 20, 1996)]
[Rules and Regulations]
[Pages 49409-49411]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-23851]
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Rules and Regulations
Federal Register
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Federal Register / Vol. 61, No. 184 / Friday, September 20, 1996 /
Rules and Regulations
[[Page 49409]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-NM-223-AD; Amendment 39-9764; AD 96-19-17]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 757 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 certain Boeing Model 757 series airplanes. This action
requires a one-time inspection to detect discrepancies of the main
battery shunt, and replacement with a serviceable part, if necessary.
This action also requires inspection of certain wires, washers, and
brass jam nuts to detect any discrepancy, and replacement with a
serviceable part, if necessary. Additionally, this action requires
inspection, and adjustment if necessary, of the torque and resistance
of the installation of the main battery ground stud. This amendment is
prompted by a report of interruption of electrical power during flight
due to improper installation of the main battery shunt and ground stud
connection of the main battery. The actions specified in this AD are
intended to prevent such electrical power interruptions, which could
result in loss of battery power to the source of standby power for the
airplane.
DATES: Effective October 7, 1996.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of October 7, 1996.
Comments for inclusion in the Rules Docket must be received on or
before November 19, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-223-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: Stephen S. Oshiro, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington;
telephone (206) 227-2793; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: The FAA recently has received reports
indicating that interruptions of electrical power have occurred during
flight, which resulted in the loss of battery power to the hot battery
bus (HBB) on a Boeing Model 767 series airplane. The HBB is the source
of standby power to the airplane. Investigation revealed that the
reported loss of power to the HBB occurred due to cracked shunts,
improper installation of fasteners on the shunt studs, and improper
torque of shunt fasteners. It appears that the improper installation of
fasteners on the shunt studs and improper torque of shunt fasteners
occurred during manufacture.
Loose fasteners on the shunt studs can create an open circuit or
high resistance in the connection of the main battery ground stud,
which can cause an interruption of the battery charger and the loss of
the HBB. The loss of the HBB and associated loads will cause multiple
advisory level Engine Indication and Crew Alerting System (EICAS)
messages; loss of power to the standby buses/loads during standby
operation; and the potential loss of center bus power. Such loss of
standby power could adversely affect the function of the following
systems:
1. the captain's standby instruments,
2. flight control electronics,
3. Very High Frequency (VHF) communications,
4. thrust reverser control,
5. standby ignition,
6. passenger oxygen,
7. fire detection and extinguishing, and
8. wing and engine anti-ice systems, among others.
Improper installation of the main battery shunt and ground stud
connection of the main battery, if not corrected, could cause an
interruption of electrical power and loss of battery power to the HBB
during flight.
The main battery shunts of the main equipment center on the Boeing
Model 767 series airplanes are identical to those installed on the
Boeing Model 757 series airplanes; therefore, both of these models may
be subject to this same unsafe condition. The FAA has addressed this
unsafe condition in Model 767 series airplanes with the issuance of AD
96-19-10, amendment 39-9757, on September 6, 1996.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletin
757-24A0079, dated August 8, 1996, which describes procedures for
inspection of the main battery shunt to detect contaminated fasteners,
missing pressure washers or washers having an incorrect part number, or
damage to the terminal posts or to the plastic base, and replacement of
the main battery shunt, if necessary. The alert service bulletin also
describes inspection of certain wires, washers, and brass jam nuts to
detect any discrepancy, and replacement of any discrepant part with a
serviceable part.
Additionally, the alert service bulletin describes procedures for
an inspection of the main battery ground stud to verify the torque and
resistance, and adjustment of the torque and resistance, if necessary.
Explanation of the Requirements of the Rule
Since an unsafe condition has been identified that is likely to
exist or develop on Boeing Model 757 series airplanes, this AD is being
issued to prevent interruption of electrical power during flight, which
could result in loss of battery power to the source of standby power
for the airplane. This AD requires inspection of the main battery
[[Page 49410]]
shunt to detect contaminated fasteners, missing pressure washers or
washers having an incorrect part number, or damage to the terminal
posts or to the plastic base, and replacement of the main battery
shunt, if necessary. This AD also requires inspection of certain wires,
washers, and brass jam nuts to detect any discrepancy, and replacement
of any discrepant part with a serviceable part. Additionally, this AD
requires an inspection of the main battery ground stud to verify the
torque and electrical resistance, and adjustment of the torque and
resistance, if necessary. The actions are required to be accomplished
in accordance with the alert service bulletin described previously.
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 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 96-NM-223-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:
96-19-17 Boeing: Amendment 39-9764. Docket 96-NM-223-AD.
Applicability: Model 757 series airplanes, as listed in Boeing
Alert Service Bulletin 757-24A0079, dated August 8, 1996;
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 (b) 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 interruptions of electrical power during flight,
which could result in loss of battery power to the source of standby
power for the airplane, accomplish the following:
(a) Within 45 days after the effective date of this AD,
accomplish the actions specified in paragraphs (a)(1), (a)(2) and
(a)(3) of this AD, in accordance with Boeing Alert Service Bulletin
757-24A0079, dated August 8, 1996.
(1) Perform an inspection of the main battery shunt, to detect
any contaminated fasteners, missing pressure washers or washers
having an incorrect part number, or damage to terminal posts or to
the plastic base. If any discrepancy is found, prior to further
flight, replace the main battery shunt, in accordance with the alert
service bulletin.
(2) Perform an inspection of the wires, washers, and brass jam
nuts to detect any contamination or damage. If any discrepancy is
found, prior to further flight, replace the discrepant part with a
serviceable part, in accordance with the alert service bulletin.
(3) Inspect the torque and electrical resistance of the
installation of the main battery ground stud, and adjust the torque
and resistance of the ground stud, in accordance with the alert
service bulletin.
(b) 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 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(c) 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.
(d) The actions shall be done in accordance with Boeing Alert
Service Bulletin 757-24A0079, dated August 8, 1996. This
incorporation by reference was approved by the Director of the
Federal Register in
[[Page 49411]]
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.
(e) This amendment becomes effective on October 7, 1996.
Issued in Renton, Washington, on September 11, 1996.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-23851 Filed 9-19-96; 8:45 am]
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