[Federal Register Volume 69, Number 120 (Wednesday, June 23, 2004)]
[Proposed Rules]
[Pages 34971-34974]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-14181]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NM-286-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-200B, -200C, -200F, -
300, -400, -400D, and -400F Series Airplanes; and Model 747SP 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 747-200B, -
200C, -200F, -300, -400, -400D, and -400F series airplanes; and Model 
747SP series airplanes. This proposal would require repetitive 
functional tests of the auxiliary power unit (APU) and engine fire 
shutoff switches and repetitive replacements of the APU and engine fire 
shutoff switches. This proposal would also provide an optional 
terminating action for the repetitive inspections and replacements. 
This action is necessary to prevent mineral build-up on the APU and 
engine fire shutoff switches, which could lead to failure of the 
switches to discharge fire suppressant in the affected area and could 
result in an uncontrolled fire that could spread to the strut, wing, or 
aft body of the airplane. This action is intended to address the 
identified unsafe condition.

DATES: Comments must be received by August 9, 2004.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

[[Page 34972]]

Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2002-NM-286-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2002-NM-286-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 or 2000 or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplanes, 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: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 917-6501; fax (425) 917-6590.

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 action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2002-NM-286-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. 2002-NM-286-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that, during a routine 
maintenance check, several squib circuits failed when the engine fire 
extinguishing system test was performed on certain Boeing Model 747 
series airplanes. One of the reports indicated that the fire handle 
switches failed to provide current to several squibs because of 
internal continuity failures. An investigation revealed that Lucas 
humidifiers distribute air containing minerals from the potable water 
supply. The humidified air contaminates the auxiliary power unit (APU) 
and engine fire shutoff switches. This condition, if not corrected, 
could result in mineral build-up on the APU and engine fire shutoff 
switches, which could lead to failure of the switches to discharge fire 
suppressant in the affected area and could result in an uncontrolled 
fire that could spread to the strut, wing, or aft body of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-26A2274, Revision 1, dated January 9, 2003, which describes the 
following procedures:
    1. Performing repetitive functional tests of the APU and engine 
fire shutoff switches;
    2. Performing repetitive replacements of the APU and engine fire 
shutoff switches with new or serviceable switches; and
    3. Deactivation of the Lucas (also known as TRW Systemes 
Aeronautiques) flight deck humidifier, part numbers (P/N) M01AA0101, 
M01AB0101, M01AB0102, or M01AB0103, which would eliminate the need for 
the repetitive functional tests and replacements.
    Accomplishment of the actions specified in the service bulletin 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 service bulletin described previously, except as described below.

Difference Between Service Bulletin and Proposed Rule

    Operators should note that the service bulletin specifies one of 
the initial compliance times as ``after the airplane has 12 calendar 
months of service but within 18 calendar months since airplane delivery 
* * *.'' However, this proposed AD specifies the one initial compliance 
time as ``within 18 months since the date of issuance of the original 
Airworthiness Certificate or the original Export Certificate of 
Airworthiness.'' This decision is based on our determination that 
``since airplane delivery'' may be interpreted differently by different 
operators. We find that our proposed terminology is generally 
understood within the industry and records will always exist that 
establish these dates with certainty. We also did not include reference 
to ``after the airplane has 12 calendar months of service'' because 
accomplishing the initial actions within 18 months of service would 
provide an acceptable level of safety. Thus our proposed compliance 
time would include any airplanes that may have been operating since 
delivery.
    Although the service bulletin recommends accomplishing the initial 
replacement at ``18 calendar months from issue date of the service 
bulletin,'' this proposed AD requires accomplishing the replacement 
``within 36 months after the effective date of this AD.'' We find that 
a compliance time of ``within 36 months after the effective date of 
this AD'' represents an appropriate interval of time to address the 
identified unsafe condition and allows affected airplanes to continue 
to operate during that interval without compromising safety.
    Also, operators should note that the service bulletin states that 
``Operators

[[Page 34973]]

who perform the 90 calendar day inspection and the 18 calendar month 
cleaning can avoid the required test interval shown in Figure 1, by 
deactivation of the Lucas Flight Deck Humidifier.'' However, this 
proposed AD specifies that if the optional deactivation of the 
humidifier is accomplished, operators are required to replace the 
switches with new or serviceable switches before further flight 
following the deactivation. If a flight deck humidifier is deactivated 
shortly before a required replacement or a required functional test, it 
may be possible that any one of the switches could have a latent type 
of failure. To address this unsafe condition, we have added the 
requirement to replace all switches before further flight following 
deactivation of the humidifier, as stated in paragraph (e) of this 
proposed AD. We have also added requirements as stated in paragraph (f) 
of this proposed AD to ensure functional tests and replacements of 
switches are accomplished for operators that reactivate the Lucas 
humidifier.
    We have coordinated these changes with the manufacturer.

Cost Impact

    There are approximately 316 airplanes of the affected design in the 
worldwide fleet. We estimate that 50 airplanes of U.S. registry would 
be affected by this proposed AD, and that the average labor rate is $65 
per work hour. Table 1 provides the estimated costs for U.S. operators 
to comply with this proposed AD.

                                            Table 1.--Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per
                             Action                                 Work hours       airplane       Total cost
----------------------------------------------------------------------------------------------------------------
Inspection and Functional Test (per test cycle).................          10-14        $650-910   $32,500-45,500
                                                                  (depending on
                                                                       airplane
                                                                         model)
----------------------------------------------------------------------------------------------------------------

    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 proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect 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, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    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 2002-NM-286-AD.

    Applicability: Model 747-200B, -200C, -200F, -300, -400, -400D, 
and -400F series airplanes; and Model 747SP series airplanes; as 
listed in Boeing Alert Service Bulletin 747-26A2274, Revision 1, 
dated January 9, 2003; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent mineral build-up on the auxiliary power unit (APU) 
and engine fire shutoff switches, which could lead to failure of the 
switches to discharge fire suppressant in the affected area and 
could result in an uncontrolled fire that could spread to the strut, 
wing, or aft body of the airplane, accomplish the following:

Service Bulletin References

    (a) The term ``service bulletin,'' as used in this AD, means the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
26A2274, Revision 1, dated January 9, 2003.

Initial and Repetitive Functional Test

    (b) At the later of the compliance times specified in paragraphs 
(b)(1) and (b)(2) of this AD, perform a functional test of the APU 
and engine fire shutoff switches, in accordance with the service 
bulletin. Repeat the functional test thereafter at intervals not to 
exceed 18 months.
    (1) Within 18 months since the date of issuance of the original 
Airworthiness Certificate or the original Export Certificate of 
Airworthiness.
    (2) Within 90 days after the effective date of this AD.

Fire Shutoff Switch Failure

    (c) If any fire shutoff switch fails during any functional test 
required by paragraph (b) or (f) of this AD, before further flight, 
replace the switch with a new or serviceable switch, in accordance 
with the service bulletin. Repeat the switch replacement thereafter 
at intervals not to exceed 36 months.

Replacement

    (d) Within 36 months after the effective date of this AD, 
replace all APU and engine fire shutoff switches that have not been 
previously replaced per paragraph (c) of this AD with new or 
serviceable switches, in accordance with the service bulletin. 
Repeat the switch replacement thereafter at intervals not to exceed 
36 months.

Deactivation of Lucas Humidifier

    (e) Operators may terminate the repetitive requirements of 
paragraphs (b), (c), and (d) of this AD by accomplishing the actions 
in paragraphs (e)(1) and (e)(2) of this AD, except as provided by 
paragraph (f) of this AD.

[[Page 34974]]

    (1) Deactivate the Lucas humidifier, part number (P/N) 
M01AA0101, M01AB0101, M01AB0102, or M01AB0103, in accordance with 
the service bulletin.
    (2) Before further flight following the deactivation specified 
in paragraph (e)(1) of this AD, replace all APU and engine fire 
shutoff switches with new or serviceable switches in accordance with 
the service bulletin.

Reactivation of Lucas Humidifier

    (f) For any airplanes on which Lucas humidifier, P/N M01AA0101, 
M01AB0101, M01AB0102, or M01AB0103 is reactivated after the 
effective date of this AD: Do the requirements of paragraphs (f)(1) 
and (f)(2) of this AD at the times specified in those paragraphs.
    (1) Within 18 months after reactivating the humidifier, and 
thereafter at intervals not to exceed 18 months, do the functional 
test required by paragraph (b) of this AD.
    (2) Within 36 months after reactivating the humidifier, and 
thereafter at intervals not to exceed 36 months, replace all APU and 
engine fire shutoff switches that have not been previously replaced 
per paragraph (c) of this AD. Do the replacements per paragraph (d) 
of this AD.

Actions Accomplished per Previous Issue of Service Bulletin

    (g) Actions accomplished before the effective date of this AD 
per Boeing Alert Service Bulletin 747-26A2274, dated August 29, 
2002, are considered acceptable for compliance with the 
corresponding action specified in this AD.

Alternative Methods of Compliance

    (h) In accordance with 14 CFR 39.19, the Manager, Seattle 
Aircraft Certification Office, FAA, is authorized to approve 
alternative methods of compliance for this AD.

    Issued in Renton, Washington, on June 16, 2004.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-14181 Filed 6-22-04; 8:45 am]
BILLING CODE 4910-13-P