[Federal Register Volume 66, Number 179 (Friday, September 14, 2001)]
[Proposed Rules]
[Pages 47901-47903]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-23070]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-174-AD]
RIN 2120-AA64


Airworthiness Directives; Dornier Model 328-300 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Dornier Model 328-300 
series airplanes. This proposal would require, for certain airplanes, a 
one-time torque test (inspection) of the attachment bolts of the 
forward engine mount vibration isolators to determine if the bolts are 
adequately torqued, and corrective action, if necessary. For all 
airplanes, this proposal would prohibit installation of an attachment 
bolt on the forward engine mount vibration isolators, unless the 
attachment bolt is torqued within certain limits. These actions are 
necessary to prevent failure of the engine mount, which could result in 
separation of the engine from the airplane. This action is intended to 
address the identified unsafe condition.

DATES: Comments must be received by October 15, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-174-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. 2001-NM-174-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 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Fairchild Dornier, Dornier Luftfahrt GmbH, P.O. Box 1103, 
D-82230 Wessling, Germany. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Tom Groves, Aerospace Engineer, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-1503; 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 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 2001-NM-174-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. 2001-NM-174-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority 
for Germany, notified the FAA that an unsafe condition may exist on 
certain Dornier Model 328-300 series airplanes. The LBA advises that, 
during an engine replacement, it was discovered that a certain section 
of the Aircraft Maintenance Manual (AMM) provides incorrect torque 
values for the attachment bolts of the forward engine mount vibration 
isolators. Because this discrepancy exists in the AMM, it is probable 
that any airplane on which a forward engine mount has been removed or 
replaced since the airplane was manufactured has attachment bolts that 
have been inadequately torqued. This condition, if not corrected, could 
result in failure of the engine mount, which could result in separation 
of the engine from the airplane.

Explanation of Relevant Service Information

    Dornier has issued Service Bulletin SB-328J-71-109, dated March 26, 
2001, including Aircraft Maintenance Manual

[[Page 47902]]

(AMM) Temporary Revision (TR) 71-130, dated March 8, 2001. The service 
bulletin describes procedures for a one-time torque test (which the 
service bulletin refers to as an inspection) of the attachment bolts of 
the forward engine mount vibration isolators on the left- and right-
hand sides of the airplane, to determine if the bolts are adequately 
torqued, and corrective action, if necessary. If any bolt on a 
vibration isolator is inadequately torqued, the corrective action 
involves replacing all bolts on the affected isolator. Procedures for 
such replacement include performing a visual inspection to determine 
the condition of components of the vibration isolator, removing the 
existing bolts and washers that attach the forward engine mount 
vibration isolators to the engine, installing new bolts to reattach the 
forward engine mount vibration isolators to the engine, and torquing 
the new bolts to adequate torque values. Accomplishment of the actions 
specified in the service bulletin is intended to adequately address the 
identified unsafe condition.
    The LBA classified this service bulletin as mandatory and issued 
German airworthiness directive 2001-163, dated June 14, 2001, in order 
to assure the continued airworthiness of these airplanes in Germany.
    For the convenience of operators, the service bulletin includes TR 
71-130, dated March 8, 2001, which includes revised torque values for 
the attachment bolts of the forward engine mount vibration isolators.

FAA's Conclusions

    This airplane model is manufactured in Germany 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 LBA has kept the FAA informed of 
the situation described above. The FAA has examined the findings of the 
LBA, 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 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, the proposed AD would require, for certain 
airplanes, accomplishment of the actions specified in the service 
bulletin described previously, except as discussed below. For all 
airplanes, the proposed AD would prohibit installation of an attachment 
bolt on the forward engine mount vibration isolators, unless the 
attachment bolt is torqued within certain limits.

Difference Between This Proposed AD and the Foreign AD

    The foreign AD specifies a compliance time of 2,500 flight cycles 
after the first removal or reinstallation of the forward engine mount 
vibration isolator for the inspection of the attachment bolts of the 
forward engine mount vibration isolators to determine if the bolts are 
adequately torqued, and corrective action, if necessary. The FAA finds 
that, since some airplanes may have already passed this threshold, it 
is necessary to allow a grace period for compliance with this proposed 
AD, so that no airplane will be grounded upon the effective date of the 
AD. Therefore, this proposed AD would require accomplishment of the 
proposed actions within 2,500 flight cycles after the first removal or 
reinstallation of the forward engine mount vibration isolator, or 
within 30 days after the effective date of this AD, whichever comes 
later.

Difference Between This Proposed AD and the Service Bulletin

    As part of the corrective actions for any inadequately torqued bolt 
on a vibration isolator, the service bulletin specifies a visual 
inspection to determine the condition of components of the vibration 
isolator. However, the service bulletin does not specifically state 
what type of visual inspection must be done or what corrective actions 
must be done if any components of the vibration isolator are damaged. 
Review of Aircraft Maintenance Manual Job Instruction Card 71-20-00, 
which the service bulletin refers to as an additional source of service 
information for accomplishment of this inspection, show that a detailed 
visual inspection and replacement of any damaged vibration isolator 
component with a new component is necessary. Therefore, paragraph (b) 
of this proposed AD clarifies that the procedures for replacement of 
the attachment bolts for the vibration isolator include a detailed 
visual inspection to determine the condition of vibration isolator 
components and replacement of any damaged components with new ones. 
Also, Note 2 of the proposed AD defines a detailed visual inspection.

Cost Impact

    The FAA estimates that 36 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 2 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the proposed AD on U.S. operators is estimated to be 
$4,320, or $120 per airplane.
    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 proposed 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.

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 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:

[[Page 47903]]

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:

Dornier Luftfahrt GMBH: Docket 2001-NM-174-AD.

    Applicability: Model 328-300 series airplanes, on which a 
forward engine mount vibration isolator has been removed or 
reinstalled since the date of manufacture of the airplane, 
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 (d) 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 engine mount, which could result in 
separation of the engine from the airplane, accomplish the 
following:

One-Time Inspection

    (a) For airplanes on which a forward engine mount vibration 
isolator has been removed or reinstalled prior to the effective date 
of this AD: Within 2,500 flight cycles after the first removal or 
reinstallation of a forward engine mount vibration isolator, or 
within 30 days after the effective date of this AD, whichever comes 
later, do a one-time torque test (inspection) of the attachment 
bolts of the forward engine mount vibration isolators on the left- 
and right-hand sides of the airplane to determine if the bolts are 
adequately torqued, according to Dornier Service Bulletin SB-328J-
71-109, dated March 26, 2001, including Aircraft Maintenance Manual 
(AMM) Temporary Revision (TR) 71-130, dated March 8, 2001.

Replacement of Bolts

    (b) During the inspection required by paragraph (a) of this AD, 
if the torque value of any attachment bolt is found to be outside 
the limits specified in Dornier Service Bulletin SB-328J-71-109, 
dated March 26, 2001, including AMM TR 71-130, dated March 8, 2001: 
Before further flight, do all actions associated with replacing all 
bolts on the vibration isolator on which the improperly torqued bolt 
was found (including performing a detailed visual inspection to 
determine the condition of components of the vibration isolator and 
replacement of any damaged components with new components, removing 
the existing bolts and washers that attach the forward engine mount 
vibration isolators to the engine, installing new bolts to reattach 
the forward engine mount vibration isolators to the engine, and 
torquing the new bolts to adequate torque values), according to the 
service bulletin.

    Note 2: For the purposes of this AD, a detailed visual 
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.''

Torque Requirements

    (c) For all airplanes: As of the effective date of this AD, no 
one may install an attachment bolt on the forward engine mount 
vibration isolators on any airplane, unless the attachment bolt is 
torqued within the limits specified in Dornier 328-300 AMM TR 71-
130, dated March 8, 2001.

Alternative Methods of Compliance

    (d) 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, International Branch, ANM-116, 
Transport Airplane Directorate, FAA. Operators shall submit their 
requests through an appropriate FAA Principal Maintenance Inspector, 
who may add comments and then send it to the Manager, International 
Branch, ANM-116.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.

Special Flight Permits

    (e) 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.

    Note 4: The subject of this AD is addressed in German 
airworthiness directive 2001-163, dated June 14, 2001.



    Issued in Renton, Washington, on September 7, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-23070 Filed 9-13-01; 8:45 am]
BILLING CODE 4910-13-U