Airworthiness Directives; Aerospatiale Model ATR42-200, ATR42- 300, and ATR42-320 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-94-AD]

RIN 2120-AA64

Airworthiness Directives; Aerospatiale Model ATR42-200, ATR42-

300, and ATR42-320 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing

airworthiness directive (AD), applicable to certain Aerospatiale Model

ATR42-300 and ATR42-320 series airplanes, that currently requires

inspections to determine the proper installation of rivets in certain

key holes and to detect cracks in the area of the key holes where

rivets are missing; and correction of discrepancies. This action would

increase the compliance time for the existing requirements and expand

the

[[Page 57410]]

applicability of the existing AD to include additional airplanes. This

action also would require various inspections of the subject area for

discrepancies, and corrective actions, if necessary; and replacement of

certain cargo door hinges with new hinges. For certain airplanes, this

action would also require replacement of friction plates, stop

fittings, and bolts 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 fatigue cracks of the cargo door skin, certain

frames, and entry door stop fittings and friction plates, which could

result in reduced structural integrity of the airplane.

DATES: Comments must be received by November 24, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 98-NM-94-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.

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-94-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-94-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

On September 10, 1993, the FAA issued AD 93-18-04, amendment 39-

8689 (58 FR 53853, October 19, 1993), applicable to certain

Aerospatiale Model ATR42-300 and ATR42-320 series airplanes, to require

an inspection to determine the proper installation of rivets in the key

holes of certain fuselage frames; an inspection to detect cracks in

area of the key holes where rivets are missing; and correction of

discrepancies. That action was prompted by the discovery of cracks

around key holes on fuselage frames 25 and 27 where rivets were

missing. The requirements of that AD are intended to prevent the loss

of strength of the fuselage frames.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, the Direction Generale de l'Aviation

Civile (DGAC), which is the airworthiness authority for France, advises

that Aerospatiale has continued fatigue testing of Aerospatiale Model

ATR42-300 and ATR42-320 series airplanes. The DGAC has determined that,

in addition to fuselage frames 25 and 27 there are other areas that

require inspection and modification, if applicable, to ensure that

fatigue cracks do not progress undetected and reduce the structural

integrity of the airplane. These additional areas of concern include

cargo door fasteners and hinges; certain standard fuselage frames;

forward entry door stops, door stop bolts, friction and plates; and

upper corners. Additionally, the DGAC has determined that the subject

area on certain Model ATR42-200 series airplanes, which were not

affected by AD 93-18-04, is identical to that on the affected Model

ATR42-300 and ATR42-320 series airplanes. Therefore, all of these

airplanes may be subject to the unsafe condition and should have

fuselage frames 25 and 27 inspected.

Explanation of Relevant Service Information

Aerospatiale has issued Service Bulletin ATR42-53-0070, Revision 2,

dated March 22, 1993, which describes procedures for a general visual

inspection to determine the proper installation of rivets in the key

holes of certain fuselage frames; and corrective action, if necessary.

The corrective actions involve performing an eddy current inspection to

detect cracks in the area of the key holes where rivets are missing,

and installing rivets in uncracked holes.

Aerospatiale has issued Service Bulletin ATR42-52-0058, Revision 1,

dated March 1, 1995, which describes procedures for replacement of the

hinges on the cargo compartment door and fuselage with new improved

hinges. The replacement procedures include inspections for fastener

type and tolerances, hole diameters, or cracking, and repair; as

applicable.

Aerospatiale has issued Service Bulletin ATR42-53-0076, Revision 2,

dated October 15, 1996, which describes procedures for a general visual

inspection of certain fuselage frames for proper installation of

rivets, and corrective action, if necessary. The corrective actions

involve a general visual inspection for cracks in the tooling or key

holes, and installation of rivets in uncracked holes.

Aerospatiale also has issued Service Bulletin ATR42-52-0052,

Revision 1, dated March 2, 1993, which describes procedures for an eddy

current inspection of forward entry door stop holes to detect cracking;

a detailed visual inspection of forward entry door friction plates to

detect wear; and corrective action, if necessary. The corrective action

involves replacement of door stop fittings and friction plates with new

parts.

Aerospatiale also has issued Service Bulletin ATR42-52-0059, dated

February 16, 1995, which describes procedures for replacement of

forward entry door friction plates, upper corner stop fittings, and

bolts with parts of an improved design.

Accomplishment of the actions specified in the service bulletins is

intended to adequately address the identified unsafe condition. The

DGAC classified these service bulletins as

[[Page 57411]]

mandatory and issued French airworthiness directive 92-044-046(B)R2,

dated November 5, 1997, in order to assure the continued airworthiness

of these airplanes in France.

FAA's Conclusions

These airplane models are manufactured in France 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 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 supersede AD 93-18-04 to

require accomplishment of the actions specified in the service

bulletins described previously. The actions would be required to be

accomplished in accordance with the service bulletins described

previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

Operators should note that, although certain service bulletins

described previously specify that the manufacturer may be contacted for

disposition of certain repair conditions, this proposal would require

the repair of those conditions to be accomplished in accordance with a

method approved by the FAA or the DGAC (or its delegated agent). In

light of the type of repair that would be required to address the

identified unsafe condition, and in consonance with existing bilateral

airworthiness agreements, the FAA has determined that, for this

proposed AD, a repair approved by either the FAA or the DGAC would be

acceptable for compliance with this proposed AD.

Cost Impact

There are approximately 106 airplanes of U.S. registry that would

be affected by this proposed AD.

The general visual inspection of fuselage frames 25 and 27 that is

proposed in this AD action would take approximately 3 work hours per

airplane to accomplish, at an average labor rate of $60 per work hour.

Based on these figures, the cost impact of this inspection proposed by

this AD on U.S. operators is estimated to be $180 per airplane.

The cargo door hinge and skin replacement that is proposed in this

AD action would take approximately 250 work hours per airplane to

accomplish, at an average labor rate of $60 per work hour. Required

parts would cost approximately $9,880 per airplane. Based on these

figures, the cost impact of the door structure replacement proposed by

this AD on U.S. operators is estimated to be $24,880 per airplane.

The general visual inspection of the key and tooling holes that is

proposed in this AD action would take approximately 100 work hours per

airplane to accomplish, at an average labor rate of $60 per work hour.

Based on this figure, the cost impact of this inspection proposed by

this AD on U.S. operators is estimated to be $6,000 per airplane.

The eddy current and detailed visual inspections of the forward

entry door stop fitting and friction plate that are proposed in this AD

action would take approximately 2 work hours per airplane to

accomplish, at an average labor rate of $60 per work hour. Based on

this figure, the cost impact of these inspections proposed by this AD

on U.S. operators is estimated to be $120 per airplane.

The replacement of the forward entry door stop fitting, friction

plate, and upper door corner that is proposed in this AD action would

take approximately 50 work hours per airplane to accomplish. The

manufacturer has committed previously to its customers that it will

bear the cost of replacement parts. As a result, the cost of those

parts is not attributable to this proposed AD. Based on this figure,

the cost impact of the replacement proposed by this AD on U.S.

operators is estimated to be $3,000 per airplane.

The cost impact figures discussed above are based on assumptions

that no operator has yet accomplished any of the current or 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 removing amendment 39-8689 (58 FR

53853, October 19, 1993), and by adding a new airworthiness directive

(AD), to read as follows:

Aerospatiale: Docket 98-NM-94-AD. Supersedes AD 93-18-04, Amendment

39-8689.

Applicability: All Model ATR42-200, ATR42-300, and ATR42-320

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 (h) 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

[[Page 57412]]

been eliminated, the request should include specific proposed

actions to address it.

Compliance: Required as indicated, unless accomplished

previously.

To prevent fatigue cracks of the cargo door skin, certain

frames, entry door stop fittings, or friction plates, which could

result in reduced structural integrity of the airplane, accomplish

the following:

Frame 25 and 27 Inspection

(a) For airplanes having serial numbers 005 through 016

inclusive, 018 through 030 inclusive, 032 through 036 inclusive,

038, 040, 042, 043, 048 through 062 inclusive, 064 through 090

inclusive, 092 through 094 inclusive, and 096 through 228 inclusive:

Prior to the accumulation of 36,000 total flight cycles, or within

180 days after the effective date of this AD, whichever occurs

later, conduct a general visual inspection of fuselage frames 25 and

27 to verify the proper installation of a rivet in each of the key

holes, in accordance with Aerospatiale Service Bulletin ATR42-53-

0070, Revision 2, dated March 22, 1993.

Note 2: For the purposes of this AD, a general visual inspection

is defined as ``A visual examination of an interior or exterior

area, installation, or assembly to detect obvious damage, failure,

or irregularity. This level of inspection is made under normally

available lighting conditions such as daylight, hangar lighting,

flashlight, or drop-light, and may require removal or opening of

access panels or doors. Stands, ladders, or platforms may be

required to gain proximity to the area being check.''

Note 3: Inspection of fuselage frames 25 and 27 accomplished

prior to the effective date of this AD in accordance with

Aerospatiale Service Bulletin ATR42-53-0070, dated June 10, 1991, or

Revision 1, dated June 12, 1992, is considered acceptable for

compliance with the requirements of paragraph (a) of this AD.

(1) If a rivet is installed in each of the key holes, no further

action is required by this paragraph.

(2) If a rivet is not installed in each of the key holes, prior

to further flight, perform an eddy current inspection of each open

key hole to detect cracks, in accordance with the service bulletin.

(i) If no crack is found during the eddy current inspection,

prior to further flight, install a rivet in the open key hole in

accordance with the service bulletin. After such installation, no

further action is required by this paragraph for that key hole.

(ii) If any crack is found during the eddy current inspection,

prior to further flight, repair the crack in accordance with a

method approved by the Manager, International Branch, ANM-116, FAA,

Transport Airplane Directorate, or the Direction Generale de

l'Aviation Civile (DGAC) (or its delegated agent). For a repair

method to be approved by the Manager, International Branch, ANM-116,

as required by this paragraph, the Manager's approval letter must

specifically reference this AD.

Inspection and Modification of Cargo Door Structure

(b) For airplanes equipped with a cargo compartment door on

which Aerospatiale Modification 3191 has not been accomplished:

Prior to the accumulation of 27,000 total flight cycles, or within

180 days after the effective date of this AD, whichever occurs

later, except as provided by paragraph (c) of this AD, replace the

hinges on the cargo compartment door and fuselage (including

inspections for fastener type and tolerances, hole diameters, or

cracking, and repair; as applicable) with new improved hinges, in

accordance with paragraph 2. of the Accomplishment Instructions of

Aerospatiale Service Bulletin ATR42-52-0058, Revision 1, dated March

1, 1995.

(c) Where the instructions in Aerospatiale Service Bulletin

ATR42-52-0058, Revision 1, dated March 1, 1995, specify that ATR is

to be contacted for a repair, prior to further flight, repair in

accordance with a method approved by the Manager, International

Branch, ANM-116, or the DGAC (or its delegated agent).

Frame Inspection

(d) For airplanes having serial numbers 003 through 208

inclusive: Prior to the accumulation of 36,000 total flight cycles,

or within 180 days after the effective date of this AD, whichever

occurs later, conduct a general visual inspection of the identified

fuselage frames for proper installation of a rivet in each of the

tooling and key holes, in accordance with Aerospatiale Service

Bulletin ATR42-53-0076, Revision 2, dated October 15, 1996.

(1) If a rivet is installed in each of the tooling or key holes,

no further action is required by this paragraph.

(2) If a rivet is not installed in each of the tooling and key

holes, prior to further flight, perform a detailed visual inspection

of each open tooling or key hole to detect cracks, in accordance

with the service bulletin.

Note 4: 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.''

(i) If no crack is found during the detailed visual inspection

required by paragraph (d)(2) of this AD, prior to further flight,

install a rivet in the open hole in accordance with the service

bulletin.

(ii) If any crack is found during the visual inspection required

by paragraph (d)(2) of this AD, prior to further flight, repair the

crack in accordance with a method approved by the Manager,

International Branch, ANM-116, or the DGAC (or its delegated agent).

Inspection and/or Replacement of Entry Door Structure

(e) For Model ATR42-300 series airplanes having serial numbers

listed in Aerospatiale Service Bulletin ATR42-52-0052, Revision 1,

dated March 2, 1993: Except as provided by paragraph (f) of this AD,

prior to the accumulation of 10,000 total flight cycles, or within

90 days after the effective date of this AD, whichever occurs later,

accomplish the requirements of paragraphs (e)(1) and (e)(2) of this

AD.

(1) Perform an eddy current inspection of the forward entry door

stop holes to detect cracking, in accordance with the service

bulletin. If any cracking is detected, prior to further flight,

replace any cracked forward entry door stop fitting with a new

fitting, in accordance with the service bulletin.

(2) Perform a detailed visual inspection of the forward entry

door friction plates for wear, in accordance with the service

bulletin. If wear is found on any friction plate, and the wear has a

depth equal to or greater than 0.8mm (0.0315 in.), prior to further

flight, replace the friction plate with a new or serviceable part in

accordance with the service bulletin.

(f) For Model ATR42-300 series airplanes listed in Aerospatiale

Service Bulletin ATR42-52-0052, Revision 1, dated March 2, 1993,

accomplishment of the requirements of paragraph (g) of this AD at

the time specified in paragraph (e) of this AD constitutes

terminating action for the requirements of paragraph (e) of this AD.

(g) For Model ATR42-300 series airplanes listed in Aerospatiale

Service Bulletin ATR42-52-0059, dated February 16, 1995: Prior to

the accumulation of 18,000 total flight cycles, or within 180 days

after the effective date of this AD, whichever occurs later,

accomplish the requirements of paragraphs (g)(1), (g)(2), and (g)(3)

of this AD in accordance with the service bulletin.

(1) Replace the forward entry door friction plates with improved

friction plates.

(2) Replace the upper corners of the forward entry door surround

structure with improved door surround corners.

(3) Replace the forward entry door stop fittings and bolts with

improved fittings and bolts.

Alternative Methods of Compliance

(h) 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.

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 5: 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

(i) 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 6: The subject of this AD is addressed in French

airworthiness directive 92-044-046(B)R2, dated November 5, 1997.

[[Page 57413]]

Issued in Renton, Washington, on October 19, 1999.

D.L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-27792 Filed 10-22-99; 8:45 am]

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