Airworthiness Directives; Bombardier Model DHC-8-101, -102, -103, -106, -201, -202, -301, -311, and -315 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-335-AD]

RIN 2120-AA64

Airworthiness Directives; Bombardier Model DHC-8-101, -102, -103,

-106, -201, -202, -301, -311, and -315 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 Bombardier Model DHC-8-101, -

102, -103, -106, -201, -202, -301, -311, and -315 series airplanes.

This proposal would require repetitive detailed visual inspections and

high frequency eddy current inspections to detect cracking of the wing

upper skin and ladder plates at over wing access panels between certain

stations; and repair, if necessary. 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 detect and correct fatigue cracking of the wing ladder

plates, which, if not corrected, could reduce the structural integrity

of the wing.

DATES: Comments must be received by October 4, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 98-NM-335-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 Bombardier, Inc., Bombardier Regional Aircraft Division,

Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. This information

may be examined at the FAA, Transport Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington; or at the FAA, Engine and Propeller

Directorate, New

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York Aircraft Certification Office, 10 Fifth Street, Third Floor,

Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT: Franco Pieri, Aerospace Engineer,

Airframe and Propulsion Branch, ANE-171, FAA, Engine and Propeller

Directorate, New York Aircraft Certification Office, 10 Fifth Street,

Third Floor, Valley Stream, New York 11581; telephone (516) 256-7526;

fax (516) 568-2716.

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-335-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-335-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

The Transport Canada Civil Aviation (TCCA), which is the

airworthiness authority for Canada, notified the FAA that an unsafe

condition may exist on all Bombardier Model DHC-8-101, -102, -103, -

106, -201, -202, -301, -311, and -315 series airplanes. The TCCA

advises that fatigue cracking of the wing ladder plate has been found

on DHC-8 series airplanes. This cracking has been attributed to

repeated fatigue load cycles. This condition, if not corrected, could

result in reduced structural integrity of the wing.

Explanation of Relevant Service Information

Bombardier has issued de Havilland Temporary Revision TR MTC-15,

dated September 18, 1998, of the de Havilland Maintenance Program

Manual PSM 1-8-7 (for Model DHC-8-100 series airplanes); de Havilland

Temporary Revision TR MTC 2-14, dated September 18, 1998, of the de

Havilland Maintenance Program Manual PSM 1-82-7 TC (for Model DHC-8-200

series airplanes); and de Havilland Temporary Revision TR MTC 3-14,

dated September 18, 1998, of the de Havilland Maintenance Program

Manual PSM 1-83-7 TC (for Model DHC-8-300 series airplanes). These

temporary revisions describe procedures for repetitive detailed visual

inspections and high frequency eddy current (HFEC) inspections to

detect cracking of the wing upper skin and ladder plates at over wing

access panels between station YW42.00 and YW171.20.

Bombardier also has issued de Havilland Airworthiness Limitations

List Temporary Revision TR AWL-59, dated September 10, 1998, of the de

Havilland Maintenance Program Manual PSM 1-8-7 (for Model DHC-8-100

series airplanes); de Havilland Airworthiness Limitations List

Temporary Revision TR AWL2-11, dated September 10, 1998, of de

Havilland Maintenance Program Manual PSM 1-82-7 (for Model DHC-8-200

series airplanes); and de Havilland Airworthiness Limitations List

Temporary Revision TR AWL3-64, dated September 10, 1998, of de

Havilland Maintenance Program Manual PSM 1-83-7 (for Model DHC-8-300

series airplanes). These temporary revisions describe the compliance

times associated with the repetitive detailed visual inspections and

HFEC inspections described previously.

Accomplishment of the actions specified in the temporary revisions

is intended to adequately address the identified unsafe condition. The

TCCA classified these temporary revisions as mandatory and issued

Canadian airworthiness directive CF-98-30, dated August 31, 1998, in

order to assure the continued airworthiness of these airplanes in

Canada.

FAA's Conclusions

These airplane models are manufactured in Canada 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 TCCA has kept the FAA informed

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

the TCCA, 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 temporary revisions described previously,

except as discussed below.

Differences Between Proposed Rule and Service Information

Operators should note that, although the Canadian airworthiness

directive and the temporary revisions 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

TCCA (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 TCCA would be acceptable for compliance with this

proposed AD.

Operators also should note that, although the Canadian

airworthiness directive affects Bombardier Model DHC-8-314 series

airplanes, Bombardier Model DHC-8-314 series airplanes are not type

certificated in the United States. Therefore, the proposed AD does not

affect those airplanes.

Cost Impact

The FAA estimates that 166 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 40 work

hours per airplane to accomplish the proposed inspections, 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

$398,400, or $2,400 per airplane, per inspection cycle.

The cost impact figure discussed above is based on assumptions that

no

[[Page 48335]]

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:

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket 98-NM-335-

AD.

Applicability: All Model DHC-8-101, -102, -103, -106, -201, -

202, -301, -311, and -315 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 (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 detect and correct fatigue cracking of the wing ladder plates,

which if not corrected, could reduce the structural integrity of the

wing, accomplish the following:

Inspection for DHC-8-100 and -300 Series Airplanes

(a) At the applicable compliance time listed in paragraph

(a)(1), (a)(2), or (a)(3) of this AD, perform a detailed visual

inspection to detect cracking of the skin and a high frequency eddy

current (HFEC) inspection of the ladder plates at over wing access

panels between station YW42.00 and YW171.20, in accordance with de

Havilland Temporary Revision TR MTC-15, dated September 18, 1998, of

the de Havilland Maintenance Program Manual PSM-1-8-7 TC (for Model

DHC-8-100 series airplanes); or de Havilland Temporary Revision TR

MTC 3-14, dated September 18, 1998, of the de Havilland Maintenance

Program Manual PSM 1-83-7 (for Model DHC-8-300 series airplanes); as

applicable. Repeat the inspections thereafter at intervals not to

exceed 10,000 flight cycles.

(1) For airplanes that have accumulated 5,000 or fewer total

flight cycles as of the effective date of this AD, accomplish the

inspection prior to the accumulation of 10,000 total flight cycles.

(2) For airplanes that have accumulated more than 5,000 total

flight cycles, but fewer than 38,501 total flight cycles as of the

effective date of this AD, accomplish the inspection prior to the

accumulation of [5,522 + (0.8955 x N Accumulated)] total cycles. ``N

Accumulated'' is defined as the total number of flight cycles as of

the effective date of this AD.

(3) For airplanes that have accumulated 38,501 or more total

flight cycles as of the effective date of this AD, accomplish the

inspection within 1,500 flight cycles after the effective date of

this AD.

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.''

Inspection for DHC-8-200 Series Airplanes

(b) At the applicable compliance time listed in paragraph (b)(1)

or (b)(2) of this AD, perform a detailed visual inspection of the

skin and an HFEC inspection to detect cracking of the ladder plates

at over wing access panels between station YW42.00 and YW171.20, in

accordance with de Havilland Temporary Revision TR MTC 2-14, dated

September 18, 1998, of the de Havilland Maintenance Program Manual

PSM 1-82-7. Repeat the inspections thereafter at intervals not to

exceed 10,000 flight cycles.

(1) For airplanes that have accumulated 5,000 or fewer total

flight cycles as of the effective date of this AD, accomplish the

inspection prior to the accumulation of 10,000 total flight cycles.

(2) For airplanes that have accumulated more than 5,000 total

flight cycles, but fewer than 38,501 total flight cycles as of the

effective date of this AD, accomplish the inspection prior to the

accumulation of [5,522 + (0.8955 x N Accumulated)] total cycles,

where ``N Accumulated'' is defined as the total number of flight

cycles as of the effective date of this AD.

Repair

(c) If any crack is detected during any inspection required by

this AD, prior to further flight, repair in accordance with a method

approved by the Manager, New York Aircraft Certification Office

(ACO), FAA, Engine and Propeller Directorate; or the Transport

Canada Civil Aviation (TCCA) (or its delegated agent). For a repair

method to be approved by the Manager, New York ACO, as required by

this paragraph, the Manager's approval letter must specifically

reference this AD.

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, New York Aircraft Certification

Office (ACO), FAA, Engine and Propeller Directorate. Operators shall

submit their requests through an appropriate FAA Principal

Maintenance Inspector, who may add comments and then send it to the

Manager, New York ACO.

Note 3: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the New York ACO.

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 Canadian

airworthiness directive CF-98-30, dated August 31, 1998.

Issued in Renton, Washington, on August 30, 1999.

Vi L. Lipski,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-23064 Filed 9-2-99; 8:45 am]

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