[Federal Register Volume 72, Number 127 (Tuesday, July 3, 2007)]
[Proposed Rules]
[Pages 36378-36380]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-12836]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28380; Directorate Identifier 2007-NM-088-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400, 747-400D, and 
747-400F Series Airplanes; Model 757-200 Series Airplanes; and Model 
767-200, 767-300, and 767-300F Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Boeing Model 747-400, 747-400D, 747-400F, 757-200, 767-200, 
767-300, and 767-300F series airplanes. This proposed AD would require 
inspecting to determine the date code of the time delay relay for the 
cargo fire suppression system, and replacing the relay if necessary. 
This proposed AD results from a report indicating that failure of a 
time delay relay on an ELMS (electrical load management system) panel 
led to testing of other time delay relays at Boeing and at the 
supplier. Similar relays are used in the cargo fire suppression system. 
The time delay relay controls when the fire bottles discharge. We are 
proposing this AD to ensure there is sufficient fire suppressant to 
control a cargo fire if the airplane is more than the relay delay time 
from a suitable airport, which could result in an uncontrollable fire 
in the cargo compartment.

DATES: We must receive comments on this proposed AD by August 17, 2007.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9:00 
a.m. and 5:00 p.m., Monday through Friday, except Federal holidays.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for the service information identified in this 
proposed AD.

FOR FURTHER INFORMATION CONTACT: Binh V. Tran, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 917-6485; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``FAA-2007-
28380; Directorate Identifier 2007-NM-088-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in

[[Page 36379]]

the AD docket shortly after the Docket Management System receives them.

Discussion

    We have received a report indicating that failure of a time delay 
relay on a Boeing Model 777 ELMS (electrical load management system) 
panel led to testing of other time delay relays at Boeing and at the 
supplier. Similar relays are used in the cargo fire suppression system. 
Although there have been no reported in-service failures of the cargo 
fire suppression time delay relays, the testing showed that, at 
elevated temperatures, thermal expansion can cause pre-existing cracks 
in the timing module substrates to widen and cause an electrical open 
circuit that prevents power from reaching the relay coil. The relay 
operates normally at reduced temperatures.
    The time delay relays of the fire suppression system in Boeing 
Model 747-400, 747-400D, 747-400F, 757-200, 767-200, 767-300, and 767-
300F series airplanes can have the same condition. There are two Halon 
bottles in the cargo fire suppression system on these airplanes. The 
first bottle discharges immediately after the cargo fire discharge 
switch is pressed. The second bottle of fire suppressant discharges 
after a period of time controlled by the time delay relay. If there is 
a cargo fire and the time delay relay has failed, the second bottle 
will not discharge. Although the first bottle discharges, the available 
Halon may not be enough to control a cargo fire. This condition, if not 
corrected, could result in insufficient fire suppressant to control a 
cargo fire if the airplane is more than the relay delay time from a 
suitable airport, which could result in an uncontrollable fire in the 
cargo compartment.

Relevant Service Information

    We have reviewed the Boeing service bulletins listed in the 
following table.

                        Boeing Service Bulletins
------------------------------------------------------------------------
    Boeing Special Attention Service
               Bulletin--                       For Boeing Model--
------------------------------------------------------------------------
747-26-2281, dated July 24, 2006.......  747-400, 747-400D, and 747-400F
                                          series airplanes.
757-26-0051, dated July 28, 2006.......  757-200 series airplanes.
767-26-0131, dated July 24, 2006.......  767-200, 767-300, and 767-300F
                                          series airplanes.
------------------------------------------------------------------------

    The service bulletins describe procedures for inspecting the time 
delay relay in the Main Equipment Center to determine if it was 
manufactured during a certain date range, and replacing any relay 
within that date range with a relay not manufactured during that date 
range, or with a relay that has been tested by the supplier and found 
to be unaffected by the thermal expansion. The service bulletins permit 
flight for 30 days after finding a relay that was manufactured within 
the suspect date range. Accomplishing the actions specified in the 
service information is intended to adequately address the unsafe 
condition.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other airplanes 
of this same type design. For this reason, we are proposing this AD, 
which would require accomplishing the actions specified in the service 
information described previously.
    Operators should note that, consistent with the Boeing service 
information, this proposed AD allows operators to continue flight for 
30 days after finding a relay that was manufactured within the suspect 
date range. In making this determination, we consider that, in the case 
of this AD, long-term continued operational safety is adequately 
assured by replacing a suspect relay within the specified time limit.

Costs of Compliance

    There are about 1,871 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 702 airplanes of 
U.S. registry. The proposed inspection would take about 1 work hour per 
airplane, at an average labor rate of $80 per work hour. Based on these 
figures, the estimated cost of the proposed AD for U.S. operators is 
$56,160, or $80 per airplane.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the 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. 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the AD docket. See the 
ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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.

[[Page 36380]]

Sec.  39.13  [Amended]

    2. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2007-28380; Directorate Identifier 2007-NM-
088-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by August 
17, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to the Boeing airplane models, certificated 
in any category, identified in the service bulletins specified Table 
1 of this AD.

                   Table 1.--Applicability of This AD
------------------------------------------------------------------------
                                         As identified in Boeing Special
             Boeing model--                Attention Service Bulletin--
------------------------------------------------------------------------
747-400, 747-400D, and 747-400F series   747-26-2281, dated July 24,
 airplanes.                               2006.
757-200 series airplanes...............  757-26-0051, dated July 28,
                                          2006.
767-200, -300, and -300F series          767-26-0131, dated July 24,
 airplanes.                               2006.
------------------------------------------------------------------------

Unsafe Condition

    (d) This AD results from a report indicating that failure of a 
time delay relay on a Boeing Model 777 ELMS (electrical load 
management system) panel led to testing of other time delay relays 
at Boeing and at the supplier. Similar relays are used in the cargo 
fire suppression system. We are issuing this AD to ensure there is 
sufficient fire suppressant to control a cargo fire if the airplane 
is more than the relay delay time from a suitable airport, which 
could result in uncontrollable fire in the cargo compartment.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Service Bulletin Reference

    (f) The term ``service bulletin,'' as used in this AD, means the 
Accomplishment Instructions of the following service bulletins, as 
applicable:
    (1) For Model 747-400, 747-400D, and 747-400F series airplanes: 
Boeing Special Attention Service Bulletin 747-26-2281, dated July 
24, 2006;
    (2) For Model 757-200 series airplanes: Boeing Special Attention 
Service Bulletin 757-26-0051, dated July 28, 2006; and
    (3) For Model 767-200, -300, and -300F series airplanes: Boeing 
Special Attention Service Bulletin 767-26-0131, dated July 24, 2006.

Inspection

    (g) Within 24 months after the effective date of this AD: Do a 
general visual inspection of the part number (P/N) TDH6103-1204, -
1804, and -6003 time delay relay, as applicable, in the Main 
Equipment Center to determine if the relay was manufactured during a 
certain date range, in accordance with the applicable service 
bulletin.

Replacement

    (h) Within 30 days after finding a relay manufactured during the 
date range specified in the service bulletin, as required by 
paragraph (g) of this AD: Replace the relay with a relay that was 
not manufactured during the specified date range, or with a relay 
that has been tested by the supplier and found to be unaffected by 
thermal expansion, in accordance with the applicable service 
bulletin.

Parts Installation

    (i) As of the effective date of this AD, no person may install a 
time delay relay, P/N TDH6103-1204, -1804, or -6003, on any airplane 
if the relay has a date code between 0000 and 0343 and does not have 
an additional date code with the letter ``T.''

Alternative Methods of Compliance (AMOCs)

    (j)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your appropriate principal inspector (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.

    Issued in Renton, Washington, on June 22, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-12836 Filed 7-2-07; 8:45 am]
BILLING CODE 4910-13-P