[Federal Register Volume 64, Number 169 (Wednesday, September 1, 1999)]
[Rules and Regulations]
[Pages 47653-47656]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-22532]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-111-AD; Amendment 39-11282; AD 99-18-16]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400, 757-200, 767-200, 
and 767-300 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 747-400, 757-200, 767-200, and 
767-300 series airplanes. This action requires repetitive checks to 
detect certain failures in the warning electronic unit (WEU) or modular 
avionic warning electronic assembly (MAWEA); repetitive tests to detect 
any failure of tactile, visual, or aural alert generated by the WEU or 
MAWEA; and corrective action, if necessary. This AD also provides for 
an optional terminating action for the repetitive checks and tests. 
This amendment is prompted by a report of a MAWEA power supply failure 
due to inadequate over-voltage protection. The actions specified in 
this AD are intended to detect and correct such a failure, which could 
result in loss of visual, aural, and tactile alerts to the flightcrew. 
Absence of such alerts could result in the flightcrew being unaware 
that an immediate or appropriate action should be taken in the event of 
an unsafe condition.

DATES: Effective September 16, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 16, 1999.
    Comments for inclusion in the Rules Docket must be received on or 
before November 1, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-

[[Page 47654]]

111-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: Sheila I. Mariano, 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) 227-2675; fax (425) 
227-1181.

SUPPLEMENTARY INFORMATION: The FAA has received a report that, during a 
production flight test of a Boeing Model 747-400 series airplane, the 
flight test group noticed a power supply failure on the status page of 
the engine indication and crew alerting system (EICAS). Investigation 
revealed that the automated bench test procedure for the modular 
avionic warning electronic assembly (MAWEA) overstressed the 5.7 volt 
over-voltage clamp circuit which resulted in the failure of the circuit 
to protect the warning cards in the MAWEA. A slow failure of the MAWEA 
power supply could result in the gradual degradation of available 
visual, aural, and tactile alerts. Absence of such alerts could result 
in the flightcrew not being aware and not taking immediate or 
appropriate action in the event of an unsafe condition (i.e., a fire, 
overspeed condition, autopilot disconnect, stall, not in takeoff 
configuration, or landing gear not extended).
    The warning electronic unit (WEU) power supply units on certain 
Boeing 757-200, 767-200, and 767-300 series airplanes are identical to 
those on the MAWEA power supply on the affected Boeing Model 747-400 
series airplanes. Therefore, all of these airplanes may be subject to 
the same unsafe condition.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletins 747-31-
2288, dated December 17, 1998, and Revision 1, dated January 28, 1999 
(for Model 747-400 series airplanes); 757-31-0066, Revision 1, dated 
December 17, 1998 (for Model 757-200 series airplanes); and 767-31-
0106, Revision 1, dated December 17, 1998 (for Model 767-200 and 767-
300 series airplanes). These service bulletins describe procedures for 
replacement (including system functional tests) of the MAWEA or WEU 
power supply with a new power supply.

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 747-400, 757-200, 767-200, and 
767-300 series airplanes of the same type design, this AD is being 
issued to detect and correct failure of the MAWEA or WEU, which could 
result in loss of any visual, aural, or tactile alert to the flightcrew 
when an unsafe condition exists. This AD requires repetitive checks of 
the status page on the EICAS display system for any MAWEA or WEU 
failure; repetitive system functional tests to detect the loss of any 
visual, aural, or tactile alert; and replacement of the MAWEA or WEU 
power supply with a new power supply, if necessary. This AD also 
provides for an optional terminating action for the repetitive checks 
and functional tests. The replacement, if accomplished, shall be 
accomplished in accordance with the service bulletins described 
previously.

Interim Action

    This is considered to be interim action. The FAA may consider 
further rulemaking action to require the accomplishment of the optional 
terminating action currently specified in this AD. However, the 
proposed compliance time for accomplishment of that action is 
sufficiently long so that prior notice and time for public comment will 
be practicable.

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 99-NM-111-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.

[[Page 47655]]

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:

99-18-16 Boeing: Amendment 39-11282. Docket 99-NM-111-AD.

    Applicability: Model 747-400 series airplanes, line numbers 1121 
through 1177 inclusive; Model 757-200 series airplanes, line numbers 
761 through 828 inclusive; and Model 767-200 and 767-3300 series 
airplanes, line numbers 668 through 723 inclusive; equipped with 
either a modular avionics warning electronic assembly (MAWEA) or a 
warning electronics unit (WEU) power supply, part number 285T0035-
201; 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 (f) 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 detect and correct failure of the MAWEA or WEU, which could 
result in a gradual degradation and eventual loss of visual, aural, 
or tactile alerts to the flightcrew, accomplish the following:

Model 747-400 Series Airplanes: Checks and Functional Tests

    (a) For Model 747-400 series airplanes: Within 15 days after the 
effective date of this AD, check the status page of the engine 
indication and crew alerting system (EICAS) for any MAWEA failure; 
and perform the system functional tests required by paragraphs 
(a)(1), (a)(2), (a)(3), (a)(4), and (a)(5) of this AD to detect loss 
of any visual, aural, or tactile alert. Thereafter, repeat the EICAS 
status page check and the system functional tests before each 
flight.

    Note 2: The following tests are an abbreviated version of 
Section 3, Work Instructions, of Boeing Service Bulletin 747-31-
2288, dated December 17, 1998, and Revision 1, dated January 28, 
1999.

    (1) Perform a takeoff (T/O) configuration warning test to check 
the T/O configuration warning card, master monitors A and B, and 
left and right aural synthesizer cards.
    (i) Set the parking brake.
    (ii) Initiate the following central maintenance computer (CMC) 
ground test--31 indication/recording: T/O warning.
    (iii) Verify that the left and right master warning lights (MWL) 
illuminate and the siren is heard from both the left and right 
speakers.
    (2) Perform an altitude alert test to check the crew alert 
module.
    (i) Verify the parking brake is still set.
    (ii) Set the selected altitude on the mode control panel (MCP) 
to approximately 400 feet above the current altitude.
    (iii) Verify that the box around the current altitude on the 
altitude tape becomes bright white.
    (iv) Set the selected altitude on the MCP to 10,000 feet.
    (v) Verify the aural warning owl is not activated.
    (3) Perform a stall warning test to check the left and right 
stall management module cards.
    (i) Ensure that the air data computers (ADC) are operational.
    (ii) Initiate the following CMC ground test--27 stall warning: 
Left.
    (iii) Verify that both stick shakers activate.
    (iv) Initiate the following CMC ground test--27 stall warning: 
Right.
    (v) Verify that both stick shakers activate.
    (4) Perform an autopilot (A/P) disconnect test to check the left 
and right clacker wailer card.
    (i) Press and hold the A/P disconnect on either control wheel.
    (ii) Verify the wailer aural is heard over the left and right 
speakers and MWL's.
    (iii) Release the A/P disconnect switch.
    (5) Perform a MAWEA card light emitting diode (LED) test per 
Airplane Maintenance Manual (AMM) task 31-51-00-715-014, ``MAWEA 
operational test,'' to verify that no red LED on the MAWEA circuit 
cards illuminate.

    Note 3: The EICAS status page check and the system functional 
tests are considered maintenance functions that require airplane log 
book entree and maintenance release prior to flight.

Model 757-200, 767-200, and 767-300 Series Airplanes: Checks and 
Functional Tests

    (b) For Model 757-200, 767-200, and 767-300 series airplanes: 
Within 15 days after the effective date of this AD, check the status 
page of the EICAS for any WEU failure; and perform the Work 
Instructions in Section 3, Part 1, of Boeing Service Bulletin 757-
31-0066, Revision 1, dated December 17, 1998 (for Model 757-200 
series airplanes); or Boeing Service Bulletin 767-31-0106, Revision 
1, dated December 17, 1998 (for Model 767-200 and 767-300 series 
airplanes); as applicable; to detect loss of any visual, aural, or 
tactile alert. Thereafter, repeat the EICAS status page check and 
the Work Instructions in Section 3, Part 1 of the applicable service 
bulletin before each flight.

    Note 4: The EICAS status page check and performance of the Work 
Instructions in Section 3, Part 1, of the applicable service 
bulletin are considered maintenance functions that require airplane 
log book entree and maintenance release prior to flight.

Corrective Action

    (c) If any failure of the MAWEA or WEU, as applicable, or the 
loss of any visual, aural, or tactile alert is detected during any 
test required by either paragraph (a) or (b) of this AD, prior to 
further flight, replace the power supply of the MAWEA or WEU with a 
new power supply, P/N 285T0035-202 Mod A, in accordance with either 
Boeing Service Bulletin 747-31-2288, dated December 17, 1998, or 
Revision 1, dated January 28, 1999 (for Model 747-400 series 
airplanes); 757-31-0066, Revision 1, dated December 17, 1998 (for 
Model 757-200 series airplanes); or 767-31-0106, Revision 1, dated 
December 17, 1998 (for Model 767-200 and 767-300 series airplanes); 
as applicable. Accomplishment of this action constitutes terminating 
action for the repetitive inspection requirements of this AD.

    Note 5: Page 59 of Boeing Service Bulletin 747-31-2288, Revision 
1, dated January 28, 1999, incorrectly references the Boeing 767 AMM 
as the appropriate source of service information for accomplishment 
of the removal and installation of the power supply. However, the 
correct reference is the Boeing 747 AMM.

Spares

    (d) As of the effective date of this AD, no person shall install 
a MAWEA or WEU power supply, part number 285T0035-201, on any 
airplane.

Optional Terminating Action

    (e) Replacement of the power supply of the MAWEA or WEU with a 
new power supply, P/N 285T0035-202 Mod A, in accordance with Boeing 
Service Bulletin 747-31-2288, dated December 17, 1998, or Revision 
1, dated January 28, 1999 (for Model 747-400 series airplanes); 757-
31-0066, Revision 1, dated December 17, 1998 (for Model 757-200 
series airplanes); or 767-31-0106, Revision 1, dated December 17, 
1998 (for Model 767-200 and 767-300 series airplanes); as 
applicable; constitutes terminating action for the repetitive system 
functional tests and EICAS status page checks required by this AD.

Alternative Methods of Compliance

    (f) 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 6: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Manager, Seattle ACO.

[[Page 47656]]

Special Flight Permits

    (g) 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.

Incorporation by Reference

    (h) The replacement, if accomplished, shall be done in 
accordance with Boeing Service Bulletin 747-31-2288, dated December 
17, 1998, or Boeing Service Bulletin 747-31-2288, Revision 1, dated 
January 28, 1999; Boeing Service Bulletin 757-31-0066, Revision 1, 
dated December 17, 1998; or Boeing Service Bulletin 767-31-0106, 
Revision 1, dated December 17, 1998; as applicable. 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.
    (i) This amendment becomes effective on September 16, 1999.

    Issued in Renton, Washington, on August 24, 1999.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-22532 Filed 8-31-99; 8:45 am]
BILLING CODE 4910-13-P