Airworthiness Directives; Aerospatiale Model SN-601 (Corvette) Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-365-AD]

RIN 2120-AA64

Airworthiness Directives; Aerospatiale Model SN-601 (Corvette)

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 all Aerospatiale Model SN-601

(Corvette) series airplanes. This proposal would require repetitive

inspections, and repair if necessary, of the locking indication system

of the drag strut jack on the main landing gear (MLG) to detect

corrosion and damage resulting from its operation. This proposal would

also require replacement of seals and backup rings with new parts. This

proposal is prompted by issuance of mandatory continuing airworthiness

information by a foreign civil airworthiness authority. The actions

specified by the proposed AD are intended to prevent failure of the

locking indication system of the drag strut jack on the MLG due to

corrosion. Such corrosion could prevent the MLG from locking and result

in the subsequent collapse of the MLG.

DATES: Comments must be received by October 12, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-114,

Attention: Rules Docket No. 98-NM-365-AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055-4056. Comments may be inspected at this

location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except

Federal holidays.

The service information referenced in the proposed rule may be

obtained from Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex

03, France. This information may be examined at the FAA, Transport

Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager,

International Branch, ANM-116, FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)

227-2110; 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 notice may be changed in

light of the comments received.

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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 notice must submit a self-addressed,

stamped postcard on which the following statement is made: ``Comments

to Docket Number 98-NM-365-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. 98-NM-365-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

The Direction Generale de l'Aviation Civile (DGAC), which is the

airworthiness authority for France, notified the FAA that an unsafe

condition may exist on all Aerospatiale Model SN-601 (Corvette) series

airplanes. The DGAC advises that one occurrence of corrosion has been

reported in the locking indication system of the drag strut jack on the

main landing gear (MLG). Such corrosion could cause failure of the

locking indication system of the drag strut jack, which could prevent

the MLG from locking and result in the subsequent collapse of the MLG.

Explanation of Relevant Service Information

Messier-Dowty, the manufacturer of the affected MLG, has issued

Technical Instruction No. 20403, Issue 2, dated March 1998, which

describes procedures for repetitive inspections to detect corrosion and

other damage, and repair if necessary, of the locking indication system

of the drag strut jack on the MLG. The Technical Instruction also

describes procedures for verification of the free displacement of the

plungers, replacement of damaged parts with new parts, and replacement

of all seals and back up rings with new parts. Accomplishment of the

actions specified in the technical instruction is intended to

adequately address the identified unsafe condition. The DGAC classified

this technical instruction as mandatory and issued French airworthiness

directive 98-179-021(B), dated May 6, 1998, in order to assure the

continued airworthiness of these airplanes in France.

FAA's Conclusions

This airplane model is manufactured in France 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 DGAC has kept the FAA informed

of the situation described above. The FAA has examined the findings of

the DGAC, 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 accomplishment of

the actions specified in the technical instruction described

previously.

Cost Impact

The FAA estimates that 2 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 8 work

hours per airplane to accomplish the proposed inspection, and that the

average labor rate is $60 per work hour. The cost of required parts

would be minimal. Based on these figures, the cost impact of the

proposed AD on U.S. operators is estimated to be $960, or $480 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.

Regulatory Impact

The regulations proposed herein would 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

proposal would not have sufficient federalism implications to warrant

the preparation of a Federalism Assessment.

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:

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:

Aerospatiale: Docket 98-NM-365-AD.

Applicability: All Model SN-601 (Corvette) series airplanes,

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 (b) 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 locking indication system of the drag

strut jack on the main landing gear (MLG) due to corrosion that

could prevent the MLG from locking and result in the subsequent

collapse of the MLG, accomplish the following:

(a) Within 3,600 flight hours or 36 months after the effective

date of this AD, whichever

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occurs first, perform a detailed visual inspection to detect certain

discrepancies of the locking indication system on the drag strut

jack on the MLG, in accordance with Messier-Dowty Technical

Instruction No. 20403, Issue 2, dated March 1998. Prior to

reassembling the parts, replace all the seals and backup rings with

new parts, in accordance with the Technical Instruction.

(1) If no corrosion is found on either plunger, prior to further

flight, inspect for the free displacement of both plungers, in

accordance with the Technical Instruction.

(i) If the displacement of both plungers is free without any

hard points, repeat the inspection required by paragraph (a) of this

AD thereafter at intervals not to exceed 72 months.

(ii) If the displacement of either plunger is not free, prior to

further flight, replace the plunger with a new plunger, in

accordance with the Technical Instruction. Repeat the inspection

required by paragraph (a) of this AD thereafter at intervals not to

exceed 72 months.

(2) If corrosion is found on either plunger, prior to further

flight, replace the plunger with a new plunger, in accordance with

the Technical Instruction. Repeat the inspection thereafter at

intervals not to exceed 72 months.

(3) If no corrosion, marking, binding, or peening is found on

any disassembled part removed from the stacking, other than the

plungers, repeat the inspection thereafter at intervals not to

exceed 72 months.

(4) If any corrosion, marking, binding or peening is found on

any disassembled parts removed from the stacking, other than the

plungers, prior to further flight, replace the part with a new part,

in accordance with the Technical Instruction. Repeat the inspection

thereafter at intervals not to exceed 72 months.

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.''

Alternative Methods of Compliance

(b) 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, 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, 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

(c) 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 French

airworthiness directive 98-179-021(B), dated May 6, 1998.

Issued in Renton, Washington, on September 3, 1999.

Dorenda D. Baker,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-23621 Filed 9-9-99; 8:45 am]

BILLING CODE 4910-13-P