[Federal Register Volume 63, Number 193 (Tuesday, October 6, 1998)]
[Rules and Regulations]
[Pages 53562-53564]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-26659]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-272-AD; Amendment 39-10819; AD 98-21-11]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-700 and -800 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 737-700 and -800 series 
airplanes. This action requires a one-time inspection to determine the 
serial numbers of the fire detector assemblies and elements for the 
auxiliary power unit (APU) and engines, and replacement of the 
assemblies or elements with new or serviceable parts, if necessary. 
This amendment is prompted by a report indicating that certain fire 
detector elements were not checked for leaks during manufacturing and, 
therefore, may not have the correct set points for the fire warning 
system. The actions specified in this AD are intended to prevent 
failure of the APU or engine fire detection systems to detect a fire in 
a timely manner, which could result in egress of an APU or engine 
compartment fire to other parts of the airplane.

DATES: Effective October 21, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before December 7, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-272-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    Information pertaining to this AD may be examined at the FAA, 
Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., 
Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Bernie Gonzalez, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2682; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: The FAA has received a report from the 
manufacturer of the auxiliary power unit (APU) and engine fire 
detectors installed on Boeing Model 737-700 and -800 series airplanes 
indicating that certain fire detector elements were not checked for 
leaks during manufacturing and may be leaking helium gas. Any leaking 
would cause the set point for the fire warning system to rise, which 
may lead to an undetected fire and delayed flight crew response. 
Failure of the APU or engine fire detection system to detect a fire in 
a timely manner, if not corrected, could result in egress of an APU or 
engine compartment fire to other parts of the airplane.

FAA's Determination

    In order to ensure that APU and engine fire detection assemblies 
and elements that were not checked for leaks during manufacturing are 
not installed on the affected airplanes, the FAA has determined that 
verification of the serial numbers of these components, and replacement 
of parts having certain serial numbers, is necessary. Accomplishment of 
these actions will adequately address failure of the APU or engine fire 
detection system.

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 737-700 and -800 series 
airplanes of the same type design, this AD is being issued to prevent 
failure of the APU or engine fire detection system to detect a fire in 
a timely manner, which could result in egress of an APU or engine 
compartment fire to other parts of the airplane. This AD requires a 
one-time inspection to determine the serial numbers of the fire 
detector assemblies and elements for the APU and engines, and 
replacement of the assemblies or

[[Page 53563]]

elements with new or serviceable parts, if necessary. The actions are 
required to be accomplished in accordance with the Boeing 737 Aircraft 
Maintenance Manual.

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 98-NM-272-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, 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:

98-21-11  Boeing: Amendment 39-10819. Docket 98-NM-272-AD.

    Applicability: Model 737-700 and -800 series airplanes; line 
positions 1 through 81 inclusive, except line positions 73 and 80; 
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 (c) 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 failure of the auxiliary power unit (APU) or engine 
fire detection system to detect a fire in a timely manner, which 
could result in egress of an APU or engine compartment fire to other 
parts of the airplane, accomplish the following:
    (a) Within 21 days after the effective date of this AD, perform 
a one-time inspection of the APU and engine fire detector assemblies 
to determine the serial number of the assemblies and the elements. 
Replace any fire detector assembly or element as required by 
paragraph (a)(1), (a)(2), or (a)(3) of this AD in accordance with 
procedures specified in Chapters 26-11-01-401 and 26-15-01-401 of 
the Boeing 737 Aircraft Maintenance Manual, as applicable.

    Note 2: The serial number of the fire detector assembly is 
stamped on the support tube.

    (1) If any assembly having a serial number 100 through 999 
inclusive is installed, prior to further flight, replace it with a 
new or serviceable assembly having a serial number 1000 or higher.
    (2) If any element of the APU fire detectors having a serial 
number 1 through 1999 inclusive is installed, prior to further 
flight, replace it with a new or serviceable element having a serial 
number 2000 or higher.
    (3) If any element of the engine fire detectors having a serial 
number 1 through 4999 inclusive is installed, prior to further 
flight, replace it with a new or serviceable element having a serial 
number 5000 or higher.
    (b) As of the effective date of this AD, no person shall install 
on any airplane an APU or engine fire detector assembly or element 
having a serial number listed in paragraph (b)(1), (b)(2), or (b)(3) 
of this AD.
    (1) For the APU or engine fire detector assembly: Boeing part 
numbers S332T100-27, -28, -29, -30, -31, -38, -42, -43, and -44; 
Whittaker part numbers 902013, 902014, 902015-01, 902016-01, 902017-
01, 902018-01, 902020, 902862, and 902864; serial numbers 100 
through 999 inclusive.
    (2) For APU fire detector elements: Whittaker part numbers 8880-
01, -02, and -03; serial numbers 1 through 1999 inclusive.
    (3) For engine fire detector elements: Whittaker part numbers 
8870-01, -02, -03, and -04; serial numbers 1 through 4999 inclusive.
    (c) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (d) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the

[[Page 53564]]

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.
    (e) This amendment becomes effective on October 21, 1998.

    Issued in Renton, Washington, on September 29, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-26659 Filed 10-5-98; 8:45 am]
BILLING CODE 4910-13-P