[Federal Register Volume 61, Number 198 (Thursday, October 10, 1996)]
[Rules and Regulations]
[Pages 53035-53038]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-25814]



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  Federal Register / Vol. 61, No. 198 / Thursday, October 10, 1996 / 
Rules and Regulations  

[[Page 53035]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-205-AD; Amendment 39-9767; AD 96-20-01]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777-200 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 777-200 series airplanes. This 
action requires a one-time inspection to determine the serial numbers 
of various switch modules on the overhead panel and control stand, and 
replacement of switch modules with new improved modules. This AD also 
requires repetitive tests of the cargo fire extinguishing system, and 
one-time tests of the fuel crossfeed valve, pack, trim air, and 
alternate flap control switches; and repair or replacement of switch 
modules with new improved modules, if necessary. This amendment is 
prompted by a report indicating that the flight crew received a warning 
of fire in the forward cargo compartment during flight; later 
inspection revealed that the metered fire bottles failed to discharge 
due to suspected contamination of the arming switch contacts of the 
cargo fire extinguishing system. The actions specified in this AD are 
intended to minimize contamination of the switch contacts and 
consequent failure of the switches, which, if not corrected, could 
result in inability of the flight crew to activate the cargo fire 
extinguishing, fuel, air conditioning, and alternate flap systems.

DATES: Effective October 25, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 25, 1996.
    Comments for inclusion in the Rules Docket must be received on or 
before December 9, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-205-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: Jeffrey Duven, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington; telephone (206) 227-
2688; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: The FAA received a report indicating that 
the flight crew received a warning of fire in the forward cargo 
compartment of a Boeing Model 777-200 series airplane during flight. In 
response to the warning, the flight crew pushed the forward arming and 
cargo fire discharge switches in an attempt to discharge the fire 
extinguishing bottles in the forward cargo compartment; subsequently, 
the flight crew landed the airplane safely. During a subsequent 
inspection, no evidence of smoke or fire was found in the forward cargo 
compartment. Both dump bottles of the fire extinguishing system 
(bottles 1A and 1B) had discharged. (Discharge of extinguishant from 
these dump bottles will bring a fire to a controllable level.) None of 
the three fire bottles of the metered system (bottles 2A, 2B, and 2C) 
had discharged. (If the fire bottles of the metered system do not 
discharge, the capability of the fire extinguishing system to suppress 
a sustained fire is reduced.) Additionally, the ventilation control 
mode for fire did not operate as designed. (The ventilation control for 
fire prevents smoke from entering the main deck and maintains the 
necessary concentration of Halon extinguishant in the cargo 
compartment.)
    The false fire warning may have been caused by the high moisture 
content of the cargo located in the forward cargo compartment. Moisture 
has been known to trigger false detections in other cargo smoke 
detection systems. Failure of the fire bottles to discharge may have 
been caused by contamination of the arming switch contacts of the cargo 
fire extinguishing system. This contamination is a result of particles 
originating from a component internal to the switch. The internal 
component is made from a polyester material that has been found to be 
subject to knicking and chafing during assembly and subsequent 
operation of the switch. When the switch is pushed and activated, 
particles from the polyester material can contaminate the switch 
contacts and can prevent the switch from activating.
    Subsequent to the report of the incident described previously, the 
FAA received several additional reports of failures of switches that 
are used in systems of the airplane other than the cargo fire 
extinguishing system, including the fuel, air conditioning, and 
alternate flaps systems. The FAA has determined that the switches in 
these systems are equally susceptible to the contamination described 
previously.
    Contamination of the switch contacts and consequent failure of the 
switches, if not corrected, could result in inability of the flight 
crew to activate the cargo fire extinguishing, fuel, air conditioning, 
and alternate flap systems.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
777-26A0004, dated June 21, 1996. The alert service bulletin describes 
procedures for a one-time inspection to determine the serial numbers of 
the switch modules of the forward arming switch, the aft arming switch, 
and the discharge switch of the cargo fire extinguishing system; and 
replacement of certain switch modules with new improved modules, if 
necessary. These new improved switch modules are made of a more 
resilient nylon material that will reduce contamination. The alert 
service bulletin also describes procedures for functional tests of the 
cargo fire extinguishing system following

[[Page 53036]]

accomplishment of the inspection/replacement. The alert service 
bulletin references Boeing Component Service Bulletin 233W3212-80-01, 
dated June 21, 1996, as an additional source of service information for 
accomplishment of the inspection/replacement.
    The FAA also has reviewed and approved Boeing Alert Service 
Bulletin 777-31A0013, dated August 29, 1996. The alert service bulletin 
describes procedures for a one-time inspection to determine the serial 
numbers of the switch modules of the alternate flaps arm switch on the 
P10 control stand, the forward and aft fuel crossfeed switches on the 
fuel/fuel jettison module assembly, and the left and right air 
conditioning pack and trim air switches on the air conditioning module 
assembly; and replacement of certain switch modules with new improved 
modules.
    The alert service bulletin also describes procedures for a one-time 
functional test of the fuel crossfeed valve switches; and a one-time 
operational test of the pack switches, the trim air switches, and the 
alternate flap control switches following accomplishment of the 
inspection/replacement.
    This alert service bulletin references two other service bulletins 
as additional sources of service information for accomplishing the 
inspection/replacement:
    1. Boeing Component Service Bulletin 233W3204-21-01, dated August 
29, 1996 (for the pack and trim air switches); and
    2. Boeing Component Service Bulletin 233W3203-28-01, dated August 
29, 1996 (for the fuel crossfeed valve switches).

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 777-200 series airplanes of the 
same type design, this AD is being issued to minimize contamination of 
the switch contacts and consequent failure of the switches, which, if 
not corrected, could result in inability of the flight crew to activate 
the cargo fire extinguishing, fuel, air conditioning, and alternate 
flap systems. This AD requires a one-time inspection to determine the 
serial numbers of various switch modules on the overhead panel and 
control stand, and replacement of switch modules with new improved 
modules. This AD also requires repetitive tests of the cargo fire 
extinguishing system, and one-time tests of the fuel crossfeed valve, 
pack, trim air, and alternate flap control switches; and repair or 
replacement of switch modules with new improved modules, if necessary. 
The repair is required to be accomplished in accordance with normal 
maintenance practices. Other actions are required to be accomplished in 
accordance with the alert service bulletins described previously.
    This AD also prohibits dispatch of an airplane with any air 
conditioning pack or fuel crossfeed valve inoperative until the one-
time inspection of the switch modules of alternate flaps arm switch, 
the fuel crossfeed switches, and the air conditioning pack and trim air 
switches is accomplished, switch modules are replaced (as necessary), 
and the one- time tests of the fuel crossfeed valve, pack, trim air, 
and alternate flap control switches are accomplished.

Differences Between Relevant Service Information and AD

    1. Operators should note that Boeing Alert Service Bulletin 777-
31A0013 identifies the new improved switch modules as those on which 
the first four digits of the serial number are 9544 or greater. 
However, the FAA has been advised that switch modules on which the 
first four digits of the serial number are 9634, 9635, 9636, 9637, and 
9638 were potentially subjected to excessive heat and pressure during 
the manufacturing process and are subject to internal shorting, which 
can cause malfunction of a switch. ``New improved modules'' are defined 
in this AD as those on which the first four digits of the serial number 
are 9544 or greater, excluding 9634, 9635, 9636, 9637, and 9638.
    2. In addition, the effectivity listing specified in Boeing Alert 
Service Bulletin 777-26A0004 does not address recently delivered 
airplanes having line positions 33 and subsequent. Further, the 
effectivity listing specified in Boeing Alert Service Bulletin 777-
31A0013 does not address airplanes having line positions 37 and 
subsequent. This AD, however, requires that the actions of paragraph 
(a), (b), or (c), as applicable, be accomplished on airplanes having 
line positions 1 through 40 (inclusive).
    3. While the effect of all AD's, in conjunction with section 39.3 
of the Federal Aviation Regulations (14 CFR 39.3), is to prohibit 
installation of ``bad'' parts after the deadline for their replacement, 
the FAA has determined that it is appropriate to make this prohibition 
explicit in this case because of the commonality of the part number of 
the ``bad'' and ``good'' parts. The intent of paragraph (d) of this AD 
is to ensure that any replacement of a switch module associated with 
certain flight-critical systems that is accomplished as of 30 days 
after the effective date of this AD is consistent with the original 
intent of the AD; that is, the switch module must be replaced with a 
new improved switch module [that is, a module on which the first four 
digits of the serial number are 9544 or greater (excluding 9634 through 
9638 inclusive)].

Interim Action

    The requirements of this AD are considered to be interim action. 
The FAA has determined that as many as 76 switches on these airplanes 
may be equally susceptible to the addressed contamination problems. 
This AD requires actions to address the 10 switches that are associated 
with the most flight-critical systems. The FAA is considering 
additional rulemaking to address other switches that are susceptible to 
contamination.

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.

[[Page 53037]]

    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-205-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:

96-20-01 Boeing: Amendment 39-9767. Docket 96-NM-205-AD.

    Applicability: Model 777-200 series airplanes having line 
positions 1 through 40 inclusive, 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 (e) 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 minimize contamination of the switch contacts and 
consequent failure of the switches, which, if not corrected, could 
result in inability of the flight crew to activate the cargo fire 
extinguishing, fuel, air conditioning, and alternate flap systems; 
accomplish the following:
    (a) For airplanes having line positions 1 through 40 inclusive: 
Within 30 days after the effective date of this AD, accomplish the 
requirements of paragraphs (a)(1) and (a)(2) of this AD in 
accordance with Boeing Alert Service Bulletin 777-26A0004, dated 
June 21, 1996.

    Note 2: Boeing Alert Service Bulletin 777-26A0004 references 
Boeing Component Service Bulletin 233W3212-80-01, dated June 21, 
1996, as an additional source of service information for 
accomplishment of the one-time inspection and replacement.
    (1) Perform a one-time inspection to determine the serial 
numbers of the switch modules of the forward arming switch, the aft 
arming switch, and the discharge switch of the cargo fire 
extinguishing system; in accordance with the alert service bulletin. 
If the first four digits of the serial number of the switch module 
are less than 9544, or if the first four digits of the serial number 
of the switch module are 9634, 9635, 9636, 9637, or 9638, prior to 
further flight, replace the switch module with a new improved module 
(that is, a module on which the first four digits of the serial 
number are 9544 or greater, excluding 9634 through 9638 inclusive) 
in accordance with the alert service bulletin. And
    (2) Perform a functional test of the cargo fire extinguishing 
system in accordance with paragraph III.C. of the Accomplishment 
Instructions of the alert service bulletin. Thereafter, repeat the 
functional test at intervals not to exceed 12 months.
    (i) If the cargo fire extinguishing system fails any functional 
test required by paragraph (a)(2) of this AD and the failure is 
determined to be caused by a defective switch module, prior to 
further flight, replace any discrepant switch module in that system 
with a new improved module (a module on which the first four digits 
of the serial number are 9544 or greater, excluding 9634 through 
9638 inclusive) in accordance with the alert service bulletin.
    (ii) If the cargo fire extinguishing system fails any functional 
test required by paragraph (a)(2) of this AD and the failure is 
determined to be caused by a condition other than a defective switch 
module, prior to further flight, repair in accordance with normal 
maintenance practices.
    (b) For airplanes having line positions 2 through 9 inclusive, 
11 through 13 inclusive, 15 through 17 inclusive, and 19 through 36 
inclusive: The airplane may not be dispatched with any air 
conditioning pack or fuel crossfeed valve inoperative. Once the 
actions required by paragraph (c) of this AD are accomplished, the 
airplane may be dispatched with one or both air conditioning packs 
and one fuel crossfeed valve inoperative, in accordance with the 
provisions and limitations specified in the Master Minimum Equipment 
List (MMEL).
    (c) For airplanes having line positions 1 through 40 inclusive: 
Within 30 days after the effective date of this AD, accomplish the 
requirements of paragraphs (c)(1) and (c)(2) in accordance with 
Boeing Alert Service Bulletin 777-31A0013, dated August 29, 1996.

    Note 3: Boeing Alert Service Bulletin 777-31A0013 references 
Boeing Component Service Bulletin 233W3204-21-01, dated August 29, 
1996 (for the pack and trim air switches), and Boeing Component 
Service Bulletin 233W3203-28-01, dated August 29, 1996 (for the fuel 
crossfeed valve switches), as additional sources of service 
information for accomplishment of the one-time inspection and 
replacement.

    (1) Perform a one-time inspection to determine the serial 
numbers of the switch modules of the alternate flaps arm switch on 
the P10 control stand, the forward and aft fuel crossfeed switches 
on the fuel/fuel jettison module assembly, and the left and right 
air conditioning pack and trim air switches on the air conditioning 
module assembly; in accordance with the Accomplishment Instructions 
of the alert service bulletin, with the exception of paragraph A of 
those Accomplishment Instructions. In lieu of that paragraph of the 
alert service bulletin, accomplish the following: Open the circuit 
breakers listed in Table 1 of this AD and attach ``DO-NOT-CLOSE'' 
tags:

           Table 1.--Circuit Breakers to Be Opened and Tagged           
------------------------------------------------------------------------
    Location (panel/grid)             Name             Circuit breaker  
------------------------------------------------------------------------
P110/L23....................  FUEL XFEED VLV FWD..  C28629.             

[[Page 53038]]

                                                                        
P310/G9.....................  FUEL XFEED VLV AFT..  C28612.             
P310/A8.....................  SNSR EXC 1..........  C27513.             
P310/D3.....................  FSEU 1..............  C27601.             
P210/F21....................  SNSR EXC 2..........  C27514.             
P210/K4.....................  FSEU 2..............  C27602.             
P11/D6......................  OPAS 1..............  C23603.             
P11/G20.....................  OPAS 2..............  C23602.             
P11/B7......................  OPAS 3..............  C23605.             
P210/K8.....................  SLATS ELEC CNTL RLY   C27630.             
                               PWR.                                     
P110/K17....................  FLAPS ELEC CNTL RLY   C27631.             
                               PWR.                                     
P110/F4.....................  OVHD INST & PNL LTS/  C33410.             
                               FWD PNL FLOOD LTS.                       
P110/G4.....................  AISLE STAND INST &    C33492.             
                               PNL LTS.                                 
P110/N25....................  MD & T CHANNEL 1....  C33605.             
P310/B3.....................  MD & T CHANNEL 3....  C33610.             
P310/F4.....................  MD & T CHANNEL 4....  C33611.             
P210/M3.....................  MD & T CHANNEL 5....  C33604.             
------------------------------------------------------------------------

    If the first four digits of the serial number of the switch 
module are less than 9544; or if the first four digits of the serial 
number of the switch module are 9634, 9635, 9636, 9637, or 9638; 
prior to further flight, replace the switch module with a new 
improved switch module (a module on which the first four digits of 
the serial number are 9544 or greater, excluding 9634 through 9638 
inclusive) in accordance with the alert service bulletin.

    Note 4: Opening the three OPAS circuit breakers will disable 
control of the air conditioning packs from the air conditioning 
control panel. If it is desired to turn on the air conditioning pack 
during incorporation of the alert service bulletin, the pack should 
be turned on before opening the OPAS circuit breakers.

    (2) Perform a one-time functional test of the fuel crossfeed 
valve switches, a one-time operational test of the pack switches, a 
one-time operational test of the trim air switches, and a one-time 
operational test of the alternate flap control switches in 
accordance with paragraphs III.F., III.G., III.H., and III.I., 
respectively, of the Accomplishment Instructions of the alert 
service bulletin.
    (i) If any switch module fails any test required by paragraph 
(c)(2) of this AD and the failure is determined to be caused by a 
defective switch module, prior to further flight, replace any 
discrepant switch module in that system with a new improved module 
(a module on which the first four digits of the serial number are 
9544 or greater, excluding 9634 through 9638 inclusive) in 
accordance with the alert service bulletin.
    (ii) If any switch module fails any test required by paragraph 
(c)(2) of this AD and the failure is determined to be caused by a 
condition other than a defective switch module, prior to further 
flight, repair in accordance with normal maintenance practices.
    (d) For airplanes having line positions 1 through 40 inclusive: 
As of 30 days after the effective date of this AD, no person shall 
install on any airplane a switch module on which the first four 
digits of the serial number are less than 9544, or a switch module 
on which the first four digits of the serial number are 9634, 9635, 
9636, 9637, or 9638 at the locations listed in paragraphs (d)(1) 
through (d)(6) of this AD:
    (1) the discharge switch of the cargo fire extinguishing system;
    (2) the alternate flaps arm switch on the P10 control stand;
    (3) the forward and aft arming switches of the cargo fire 
extinguishing system;
    (4) the forward and aft fuel crossfeed switches on the fuel/fuel 
jettison module assembly;
    (5) the left and right air conditioning pack switches on the air 
conditioning module assembly; and
    (6) the left and right trim air switches on the air conditioning 
module assembly.
    (e) 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 5: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (f) 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.
    (g) The inspection and replacement shall be done in accordance 
with Boeing Alert Service Bulletin 777-26A0004, dated June 21, 1996, 
and Boeing Alert Service Bulletin 777-31A0013, dated August 29, 
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.
    (h) This amendment becomes effective on October 25, 1996.

    Issued in Renton, Washington, on October 2, 1996.
Ronald T. Wojnar,


Manager, Transport Airplane Directorate, Aircraft Certification 
Service.

[FR Doc. 96-25814 Filed 10-9-96; 8:45 am]
BILLING CODE 4910-13-P