[Federal Register Volume 71, Number 89 (Tuesday, May 9, 2006)]
[Proposed Rules]
[Pages 26890-26891]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-7015]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-23673; Directorate Identifier 2005-NM-233-AD]
RIN 2120-AA64


Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. 
(EMBRAER) Model EMB-135 and EMB-145, -145ER, -145MR, -145LR, -145XR, -
145MP, and -145EP Airplanes

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

ACTION: Proposed rule; withdrawal.

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SUMMARY: The FAA withdraws a notice of proposed rulemaking (NPRM) that 
proposed a new airworthiness directive (AD) for all EMBRAER Model EMB-
135 and EMB-145, -145ER, -145MR, -145LR, -145XR, -145MP, and -145EP 
airplanes. The proposed AD would have required inspecting to determine 
the

[[Page 26891]]

part number of the ailerons. For airplanes with affected aileron part 
numbers, the proposed AD would have required reworking the aileron 
damper fitting, and for certain airplanes, replacing the rod end of the 
aileron damper assembly with an improved rod end. Since the proposed AD 
was issued, we have received new data indicating that there is no 
unsafe condition associated with structural failure of the rod end of 
the aileron damper. Accordingly, the proposed AD is withdrawn.

ADDRESSES: 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 U.S. 
Department of Transportation, 400 Seventh Street, SW., Room PL-401, 
Washington, DC. This docket number is FAA-2006-23673; the directorate 
identifier for this docket is 2005-NM-233-AD.

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:

Discussion

    We proposed to amend part 39 of the Federal Aviation Regulations 
(14 CFR part 39) with a notice of proposed rulemaking (NPRM) for a new 
AD for all EMBRAER Model EMB-135 and EMB-145, -145ER, -145MR, -145LR, -
145XR, -145MP, and -145EP airplanes. That NPRM was published in the 
Federal Register on January 25, 2006 (71 FR 4067). The NPRM would have 
required inspecting to determine the part number of the ailerons. For 
airplanes with affected aileron part numbers, the NPRM would have 
required reworking the aileron damper fitting. Also, for certain 
airplanes, the NPRM would have required replacing the rod end of the 
aileron damper assembly with an improved rod end. The NPRM resulted 
from reports of structural failure of the rod end of the aileron 
damper, which was caused by insufficient clearance between the lugs of 
the aileron damper fitting and the rod end of the aileron damper. The 
proposed actions were intended to prevent failure of the aileron 
damper, which could result in failure of the aileron actuator and 
consequent reduced controllability of the airplane.

Comments

    EMBRAER requests that we withdraw the NPRM. EMBRAER points out that 
the unsafe condition stated in the NPRM (failure of the aileron damper, 
which could result in failure of the aileron actuator and consequent 
reduced controllability of the airplane) is incorrect. While the NPRM 
was intended to address reports of structural failure of the rod end of 
the aileron damper, there is no unsafe condition caused by such a 
failure. The aileron damper was introduced to improve safety by 
increasing redundancy: the aileron damper prevents vibration of the 
aileron surface in the event of failure of both rods of the aileron 
power control actuator (PCA). Failure of the rod end of the aileron 
damper and subsequent failure of the aileron damper will not cause 
vibration of the aileron surface.
    Further, while failure of the rod ends of the aileron PCA could 
result in reduced controllability of the airplane, this unsafe 
condition is already addressed by another action. EMBRAER notes that 
the FAA has previously issued AD 99-05-04 (64 FR 13894, March 23, 
1999). That AD requires inspections to detect and correct cracking or 
failure of the rod ends of the aileron PCA on all EMBRAER Model EMB-145 
series airplanes.
    EMBRAER further states that repetitive inspections of the aileron 
damper rod ends and fitting lugs for integrity and general condition 
are specified as a Certification Maintenance Requirement (for Model 
EMB-135 airplanes) and a System Inspection Requirement (for Model EMB-
145 airplanes). The failures of the aileron damper rod ends that 
prompted the NRPM were discovered during inspections performed under 
these requirements.
    We agree with the commenter's request to withdraw the NPRM. EMBRAER 
Service Bulletin 145-27-0108, Revision 01, dated April 28, 2005, which 
the NPRM references as the appropriate source of service information 
for the required actions, was issued to correct insufficient clearance 
between the lugs of the aileron damper fitting and the rod end of the 
aileron damper. We have coordinated with EMBRAER and have determined 
that the actions in that service bulletin are not intended to address 
an unsafe condition. Doing those actions may provide an economic 
benefit to operators by preventing the need for an expensive repair in 
the event that damage is detected during routine inspections. Since 
there is no unsafe condition, the proposed AD is unnecessary.

FAA's Conclusions

    Upon further consideration, we have determined that there is no 
unsafe condition associated with structural failure of the rod end of 
the aileron damper. Accordingly, the NPRM is withdrawn.
    Withdrawal of the NPRM does not preclude the FAA from issuing 
another related action or commit the FAA to any course of action in the 
future.

Regulatory Impact

    Since this action only withdraws an NPRM, it is neither a proposed 
nor a final rule and therefore is not covered under Executive Order 
12866, the Regulatory Flexibility Act, or DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979).

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Withdrawal

    Accordingly, we withdraw the NPRM, Docket No. FAA-2006-23673, 
Directorate Identifier 2005-NM-233-AD, which was published in the 
Federal Register on January 25, 2006 (71 FR 4067).

    Issued in Renton, Washington, on April 28, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-7015 Filed 5-8-06; 8:45 am]
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