[4910-13-U] 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 [61 FR 48820  NO. 181  09/17/96]

[Docket No. 96-NM-216-AD; Amendment 39-9757; AD 96-19-10]

RIN 2120-AA64

Airworthiness Directives; Boeing Model 767 Series Airplanes

AGENCY:  Federal Aviation Administration, DOT.

ACTION:  Final rule; request for comments.

SUMMARY:  This amendment adopts a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 
767 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 reports of interruptions 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 2, 1996.
	The incorporation by reference of certain publications 
        listed in the regulations is approved by the Director of the 
Federal Register as of October 2, 1996.
	Comments for inclusion in the Rules Docket must be 
        received on or before November 18, 1996.
ADDRESSES:  Submit comments in triplicate to the Federal 
Aviation Administration (FAA), Transport Airplane 
Directorate, ANM-103, Attention:  Rules Docket No. 96-NM-
216-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:  
Chris Hartonas, Aerospace 
Engineer, Systems and Equipment Branch, ANM-130S, FAA, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, 
SW., Renton, Washington; telephone (206) 227-2864; fax 
(206) 227-1181.

SUPPLEMENTARY INFORMATION: 
The FAA recently received a report indicating that interruptions 
of electrical power occurred during flight on a Boeing Model 767 
series airplane.  These power interruptions resulted in the loss of 
battery power to the hot battery bus (HBB).  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 
messages on the Engine Indication and Crew Alerting System 
(EICAS); 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.
Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service 
Bulletin 767-24A0112, Revision 1, 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 
wire, 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 other Boeing Model 767 series 
airplanes of the same type design, this AD is being issued 
to prevent interruption of the 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 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 
wire, 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 
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-216-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. 
§ 39.13 - [Amended]
2.  Section 39.13 is amended by adding the following new 
airworthiness directive:

96-19-10  BOEING:  Amendment 39-9757.  Docket 96-NM-216-AD.
Applicability:  Model 767 series airplanes, as listed in 
Boeing Alert Service Bulletin 767-24A0112, Revision 1, 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 767-24A0112, Revision 1, 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 electrical 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 767-24A0112, Revision 1, dated August 
           8, 1996.  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.
	(e)This amendment becomes effective on October 2, 1996.

FOR FURTHER INFORMATION CONTACT:  Chris Hartonas, Aerospace 
Engineer, Systems and Equipment Branch, ANM-130S, FAA, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, 
SW., Renton, Washington; telephone (206) 227-2864; fax 
(206) 227-1181.

Last modification on 1999-06-15 by Michael Blume