AD 97-19-04

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AD Number:
97-19-04
Document Type:
AD Final Rules
Docket Number:
97-NM-221-AD
Subject Heading:
Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-145 Series Airplanes
Subject:
Auxiliary Power Unit (APU) Firewall
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
09/24/1997
Make:
Embraer S.A.
Model:
EMB-145 | EMB-145ER
Product Type:
Aircraft
Product Subtype:
Large Airplane
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39 [62 FR 47360 NO. 174 09/09/97]
Comments:
Updated RGL applicability to match AD applicability; CAR C-11-185
AIRWORTHINESS DIRECTIVES FINAL RULES: 97-19-04
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   97-NM-221-AD

AMENDMENT:   39-10124

AD NUMBER:   97-19-04

SUBJECT HEADING:   Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-145 Series Airplanes

ACTION:   Final rule; request for comments

SUMMARY:   This amendment adopts a new airworthiness directive (AD) that is applicable to certain EMBRAER Model EMB-145 series airplanes. This action requires repetitive visual inspections to detect cracks in the firewall of the auxiliary power unit (APU), and repair, if necessary. This AD also requires installation of a visco-elastic damper blanket on the firewall, which constitutes terminating action for the repetitive inspection requirements. This amendment is prompted by reports indicating that cracks were found in the firewall of the APU due to vibration of the firewall. The actions specified in this AD are intended to prevent such cracking, which could result in reduced structural integrity of the fuselage and empennage in the event that a fire penetrates through the firewall of the APU.

DATES:   Effective September 24, 1997. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of September 24, 1997. Comments for inclusion in the Rules Docket must be received on or before October 9, 1997.

ADDRESSES:   Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 97-NM-221-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
The service information referenced in this AD may be obtained from Empresa Brasileira de Aeronautica S.A. (EMBRAER), P.O. 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; or at the FAA, Small Airplane Directorate, Atlanta Aircraft Certification Office, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:   Curtis Jackson, Aerospace Engineer, Airframe and Propulsion Branch, ACE-117A, FAA, Small Airplane Directorate, Atlanta Aircraft Certification Office, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia 30349; telephone (770) 703-6083; fax (770) 703-6097.

SUPPLEMENTARY INFORMATION:  
The Departamento de Aviacao Civil (DAC), which is the airworthiness authority for Brazil, recently notified the FAA that an unsafe condition may exist on certain EMBRAER Model EMB-145 series airplanes. The CTA advises that it has received reports indicating that, during a routine inspection, cracks were found in the firewall of the auxiliary power unit (APU). In one incident, the crack was 24 inches in length. The cause of such cracking has been attributed to vibration of the firewall in the location where the recessed area of the shell is spot welded to the firewall. Cracking in the firewall of the APU, if not corrected, could result in reduced structural integrity of the fuselage and empennage in the event that a fire penetrates through the firewall of the APU.

Explanation of Relevant Service Information
EMBRAER has issued Service Bulletin 145-53-0004, dated July 28, 1997, which describes procedures for repetitive visual inspections to detect cracks in the firewall of the APU. The service bulletin also describes procedures for installation of a visco-elastic damper blanket on the firewall, which eliminates the need for the repetitive inspections. The DAC issued Brazilian airworthiness directive NPR/AD-97-145-02, dated July 30, 1997, in order to assure the continued airworthiness of these airplanes in Brazil.

FAA's Conclusions
This airplane model is manufactured in Brazil and is 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 the FAA informed of the situation described above. The FAA has 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 Rule
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, this AD is being issued to prevent cracking in the firewall of the APU, which could result in reduced structural integrity of the fuselage and empenage in the event that a fire penetrates through the firewall of the APU. This AD requires repetitive visual inspections to detect cracks in the firewall of the APU, and repair, if necessary. This AD also requires installation of a visco-elastic damper blanket on the firewall, which constitutes terminating action for the repetitive inspection requirements. The inspections and installation are required to be accomplished in accordance with the service bulletin described previously.

Differences Between the AD and the Relevant Service Information
Operators should note that, although the referenced service bulletin specifies that the manufacturer must be contacted for disposition of certain conditions, this AD requires the repair of those conditions to be accomplished in accordance with a method approved by the FAA.

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 97-NM-221-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.

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.

§ 39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive:

REGULATORY TEXT:  
97-19-04 EMPRESA BRASILEIRA DE AERONAUTICA S.A.: Amendment 39-10124. Docket 97-NM-221-AD.
Applicability: Model EMB-145 series airplanes, serial numbers 145004 through 145019 inclusive; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 cracking in the firewall of the auxiliary power unit (APU), which could result in reduced structural integrity of the fuselage and empennage in the event that a fire penetrates through the firewall of the APU, accomplish the following:

(a) Within 50 flight hours after the effective date of this AD, perform a visual inspection to detect cracks in the firewall of the APU, in accordance with EMBRAER Service Bulletin 145-53-0004, dated July 28, 1997.

(1) If no crack is detected, repeat the visual inspection thereafter at intervals not to exceed 100 flight hours.

(2) If any crack is detected, prior to operation of the APU, repair it in accordance with a method approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate.

(b) Within 200 flight hours after the effective date of this AD, install the visco-elastic damper blanket on the firewall in accordance with EMBRAER Service Bulletin 145-53-0004, dated July 28, 1997. Accomplishment of the installation constitutes terminating action for the repetitive inspection requirements of this AD.

(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, Atlanta Aircraft Certification Office (ACO), FAA, Small 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, Atlanta ACO.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO.

(d) 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.

(e) The inspection and installation shall be done in accordance with EMBRAER Service Bulletin 145-53-0004, dated July 28, 1997. 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 Empresa Brasileira de Aeronautica S.A. (EMBRAER), P.O. Box 343 - CEP 12.225, Sao Jose dos Campos - SP, Brazil. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Small Airplane Directorate, Atlanta Aircraft Certification Office, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 3: The subject of this AD is addressed in Brazilian airworthiness directive NPR/AD-97-145-02, dated July 30, 1997.

(f) This amendment becomes effective on September 24, 1997.

FOOTER: