[Federal Register Volume 69, Number 44 (Friday, March 5, 2004)]
[Proposed Rules]
[Pages 10362-10364]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-4929]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NM-218-AD]
RIN 2120-AA64


Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. 
(EMBRAER) Model EMB-135BJ and EMB-145XR Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain EMBRAER Model EMB-135BJ 
and EMB-145XR series airplanes. This proposal would require repetitive 
inspections for cracking in the firewall of the auxiliary power unit 
(APU), and repair of the firewall if necessary. This proposal would 
also provide an optional terminating action for the repetitive 
inspections. This action is necessary to detect and correct cracking in 
the APU firewall, which could result in reduced structural integrity of 
the firewall, and a consequent uncontained APU fire that could spread 
to the airplane structure. This action is intended to address the 
identified unsafe condition.

DATES: Comments must be received by April 5, 2004.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2003-NM-218-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. 2003-NM-218-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 Empresa Brasileira de Aeronautica S.A. (EMBRAER), PO Box 
343--CEP 12.225, Sao Jose dos Campos--SP, Brazil. This information may 
be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Todd Thompson, Aerospace Engineer, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-1175; fax (425) 227-1149.

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

[[Page 10363]]

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 2003-NM-218-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. 2003-NM-318-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Departmento de Aviacao Civil (DAC), which is the airworthiness 
authority for Brazil, notified the FAA that an unsafe condition may 
exist on certain EMBRAER EMB-135BJ and EMB-145XR series airplanes. The 
DAC advises that it has received reports of cracking in the firewall of 
the auxiliary power unit (APU). The cracking was caused by differential 
pressure between the inside and outside of the APU compartment. Such 
cracking, if not detected and corrected, could result in reduced 
structural integrity of the firewall and a consequent uncontained APU 
fire that could spread to the airplane structure.

Explanation of Relevant Service Information

    EMBRAER has issued Service Bulletins 145-53-0037 (for Model EMB-
145XR series airplanes), dated April 30, 2003; and 145LEG-53-0010 (for 
Model EMB-135BJ series airplanes), dated June 5, 2003. These service 
bulletins describe procedures for repetitively inspecting the APU 
firewall for cracking, and repairing the APU firewall if necessary.
    The service bulletins specify that if any crack is found it should 
be repaired per the applicable structural repair manual (SRM). If any 
crack is found that exceeds the limits specified in the applicable SRM, 
a new APU firewall should be installed per Part II of the service 
bulletin. Replacement of the APU firewall with a new part would 
eliminate the need for the repetitive inspections. The service 
bulletins also describe procedures for doing an operational test each 
time an APU firewall is replaced. Accomplishment of the actions 
specified in the service bulletins is intended to adequately address 
the identified unsafe condition. The DAC classified these service 
bulletins as mandatory and issued Brazilian airworthiness directive 
2003-07-02, dated August 18, 2003, to ensure the continued 
airworthiness of these airplanes in Brazil.

FAA's Conclusions

    These airplane models are manufactured in Brazil and are type 
certificated for operation in the United States under the provisions of 
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, the DAC has kept us informed of the 
situation described above. We have examined the findings of the DAC, 
reviewed all available information, and determined that AD action is 
necessary for products of this type design that are certificated for 
operation in the United States.

Explanation of Requirements of Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would require accomplishment of 
the actions specified in the service bulletin described previously, 
except as discussed below.
    Consistent with the findings of the DAC, the proposed AD would 
allow repetitive inspections to continue in lieu of the terminating 
action. In making this determination, we considered that long-term 
continued operational safety in this case will be adequately ensured by 
repetitive inspections to detect cracking in the APU firewall before it 
represents a hazard to the airplane.

Clarification of Repair Information

    If any cracking exceeds the limits specified in the service 
bulletin, the APU firewall must be replaced with a new APU firewall per 
the Accomplishment Instructions of the applicable service bulletin.

Cost Impact

    We estimate that 40 airplanes of U.S. registry would be affected by 
this proposed AD.
    It would take approximately 1 work hour per airplane to accomplish 
the proposed repetitive inspections, at an average labor rate of $65 
per work hour. Based on these figures, the cost impact of the proposed 
repetitive inspections on U.S. operators is estimated to be $2,600, or 
$65 per airplane, per inspection cycle.
    The cost impact figure discussed above is 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 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.
    If an operator chooses to do the optional terminating action, 
rather than continue the repetitive inspections, it would take about 60 
work hours per airplane to accomplish the replacement of the APU 
firewall, at an average labor rate of $65 per work hour. Required parts 
would cost about $7,784 per airplane. Based on these figures, we 
estimate the cost of this optional terminating action to be $11,684 per 
airplane.

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

[[Page 10364]]

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:

Empresa Brasileira De Aeronautica S.A. (EMBRAER): Docket 2003-NM-
218-AD.

    Applicability: Model EMB-135BJ series airplanes as listed in 
EMBRAER Service Bulletin 145LEG-53-0010, dated June 5, 2003; and 
Model EMB-145XR series airplanes as listed in EMBRAER Service 
Bulletin 145-53-0037, dated April 30, 2003; certificated in any 
category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To detect and correct cracking in the firewall of the auxiliary 
power unit (APU), which could result in reduced structural integrity 
of the firewall, and a consequent uncontained APU fire that could 
spread to the airplane structure, accomplish the following:

Initial Inspection

    (a) Within 200 flight hours or 90 days after the effective date 
of this AD, whichever is first: Do a detailed inspection of the APU 
firewall for cracking, per Part I of the Accomplishment Instructions 
of EMBRAER Service Bulletin 145-53-0037 (for Model EMB-145XR series 
airplanes), dated April 30, 2003; or Service Bulletin 145LEG-53-0010 
(for Model EMB-135BJ series airplanes), dated June 5, 2003; as 
applicable.

    Note 1: For the purposes of this AD, a detailed inspection is 
defined as: ``An intensive visual examination of a specific 
structural area, system, installation, or assembly to detect damage, 
failure, or irregularity. Available lighting is normally 
supplemented with a direct source of good lighting at intensity 
deemed appropriate by the inspector. Inspection aids such as mirror, 
magnifying lenses, etc., may be used. Surface cleaning and elaborate 
access procedures may be required.''

Repetitive Inspections/Repair

    (b) If no cracking is found during any inspection required by 
paragraph (a) of this AD: Repeat the inspection required by 
paragraph (a) of this AD thereafter at intervals not to exceed 200 
flight hours or 90 days, whichever is first. Accomplishment of the 
replacement specified in paragraph (d) of this AD terminates the 
repetitive inspections required by this paragraph.
    (c) If any cracking is found during any inspection required by 
paragraph (a) of this AD: Before further flight, determine if the 
cracking can be repaired per Part I of the Accomplishment 
Instructions of EMBRAER Service Bulletin 145-53-0037, dated April 
30, 2003; or Service Bulletin 145LEG-53-0010, dated June 5, 2003; as 
applicable.
    (1) If the cracking can be repaired: Before further flight, 
repair the cracking per Part I of the Accomplishment Instructions of 
the applicable service bulletin. Repeat the inspection required by 
paragraph (a) of this AD thereafter at intervals not to exceed 200 
flight hours or 90 days, whichever is first.
    (2) If the cracking cannot be repaired: Before further flight, 
replace the APU firewall with a new firewall by accomplishing all of 
the actions per Part II of the Accomplishment Instructions of the 
applicable service bulletin. Accomplishment of the replacement 
terminates the repetitive inspections required by paragraphs (b) and 
(c)(1) of this AD.

Optional Terminating Action

    (d) Replacement of the APU firewall with a new firewall by 
accomplishing all of the actions per Part II of the Accomplishment 
Instructions of EMBRAER Service Bulletin 145-53-0037, dated April 
30, 2003; or 145LEG-53-0010, dated June 5, 2003; as applicable; 
constitutes terminating action for the repetitive inspections 
required by paragraphs (b) and (c)(1) of this AD.

Alternative Methods of Compliance

    (e) In accordance with 14 CFR 39.19, the Manager, International 
Branch, ANM-116, Transport Airplane Directorate, FAA, is authorized 
to approve alternative methods of compliance for this AD.

    Note 2: The subject of this AD is addressed in Brazilian 
airworthiness directive 2003-07-02, dated August 18, 2003.


    Issued in Renton, Washington, on February 20, 2004.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-4929 Filed 3-4-04; 8:45 am]
BILLING CODE 4910-13-P