[Federal Register Volume 63, Number 171 (Thursday, September 3, 1998)]
[Proposed Rules]
[Pages 46925-46927]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-23743]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-143-AD]
RIN 2120-AA64


Airworthiness Directives; de Havilland Model DHC-7 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 all de Havilland Model DHC-
7 series airplanes, that currently requires certain structural 
inspections, and repair, if necessary. This action would require 
certain structural inspection. 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 in certain significant 
structural areas, which could reduce the structural integrity of these 
airplanes.

DATES: Comments must be received by October 5, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-143-AD, 1061 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 York Aircraft Certification Office, 10 Fifth Street, 
Third Floor, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT:
Serge Napoleon, 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) 256-7512; fax (516) 568-2716.


[[Page 46926]]


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-143-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-143-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On March 6, 1997, the FAA issued AD 97-06-08, amendment 39-9965 (62 
FR 12531, March 17, 1997), applicable to all de Havilland Model DHC-7 
series airplanes, to require certain structural inspections, and 
repair, if necessary. That action was prompted by a structural re-
evaluation, which identified certain significant structural items to 
inspect for fatigue cracking as these airplanes approach and exceed the 
manufacturer's original design life. The requirements of that AD are 
intended to prevent fatigue cracking in these areas which, if not 
detected and corrected in a timely manner, could reduce the structural 
integrity of these airplanes.

Actions Since Issuance of Previous Rule

    Since the issuance of AD 97-06-08, which identified six significant 
structural areas for repetitive structural inspections to detect 
fatigue cracking, Transport Canada Aviation (TCA), which is the 
airworthiness authority for the Canada, identified a seventh area that 
also requires repetitive structural inspections to detect fatigue 
cracking. Such cracking, if not detected and corrected in a timely 
manner, could reduce the structural integrity of these airplanes.

Explanation of Relevant Service Information

    The manufacturer has issued de Havilland Dash 7 Maintenance Manual, 
Product Support Manual (PSM) 1-7-2, Chapter 5, Section 5-60-00, 
Temporary Revisions (TR) 5-99 and 5-97, both dated December 22, 1997, 
which describe procedures for Supplementary Inspection Program (SIP) 
tasks for the additional inspection to detect cracks in the fastener 
holes located on the left and right wing at stringers 6 and 8. 
Accomplishment of this inspection will ensure the continued structural 
airworthiness of Model DHC-7 series airplanes. TCA classified these 
TR's as mandatory and issued Canadian airworthiness directive CF-94-
19R1, dated January 26, 1998, in order to assure the continued 
airworthiness of these airplanes in Canada.

FAA's Conclusions

    This airplane model is manufactured in Canada 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, TCA has kept the FAA informed of the 
situation described above. The FAA has examined the findings of TCA, 
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 State, the proposed AD would supersede AD 97-06-08 to 
continue to require certain structural inspections, and repair, if 
necessary. This proposed action also would require an additional 
structural inspection to detect cracks in the fastener holes located on 
the left and right wing at stringers 6 and 8. The actions would be 
required to be accomplished in accordance with the service information 
described previously.

Cost Impact

    There are approximately 50 airplanes of U.S. registry that would be 
affected by this proposed AD.
    The inspections that are currently required by AD 97-06-08, and 
retained in this AD, take approximately 15 work hours per airplane to 
accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of the currently required actions on 
U.S. operators is estimated to be $45,000, or $900 per airplane, per 
inspection cycle.
    The new inspection that is proposed in this AD action would take 
approximately 3 work hours per airplane to accomplish, at an average 
labor rate $60 per work hour. Based on these figures, the cost impact 
of the proposed requirements of this AD on U.S. operators is estimated 
to be $9,000, or $180 per airplane, per inspection cycle.
    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.

[[Page 46927]]

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 39-9965 (62 FR 
12531, March 17, 1997), and by adding a new airworthiness directive 
(AD), to read as follows:

De Havilland Inc.: Docket 98-NM-143-AD. Supersedes AD 97-06-08, 
Amendment 39-9965.

    Applicability: All Model DHC-7 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 (f) 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 ensure the continued structural integrity of these airplanes, 
accomplish the following:

Restatement of Requirements of AD 97-06-08, Amendment 39-9965

    (a) Within 6 months after April 21, 1997 (the effective date of 
AD 97-06-08, amendment 39-9965), incorporate into the FAA-approved 
maintenance inspection program the inspections and inspection 
intervals defined in DHC-7 Maintenance Manual (PSM 1-7-2), Chapter 
5, Section 5-06-00, Temporary Revision (TR 5-84), dated June 15, 
1994; and inspect the significant structural items prior to the 
thresholds specified in TR 5-84 of PSM 1-7-2. Repeat the inspections 
thereafter at the intervals specified in TR 5-84 of PSM 1-7-2.
    (b) Prior to further flight, repair any discrepancies detected 
during any inspection required by paragraph (a) of this AD in 
accordance with one of the following:
    (1) The DHC-7 Maintenance Manual; or
    (2) The DHC-7 Structural Repair Manual; or
    (3) Other data meeting the certification basis of the airplane 
which is approved by the Manager, New York Aircraft Certification 
Office (ACO), FAA, Engine and Propeller Directorate; or
    (4) Data meeting the certification basis of the airplane which 
is approved by Transport Canada Aviation.

New Requirements of This AD

    (c) Incorporate into the FAA-approved maintenance inspection 
program the inspections and inspection intervals defined in the DHC-
7 Maintenance Manual PSM 1-7-2, Supplementary Inspection Program 
(SIP), Chapter 5, Section 5-60-00, Temporary Revision (TR 5-99), 
dated December 22, 1997, at the applicable time specified in 
paragraph (c)(1) or (c)(2) of this AD; and inspect the significant 
structural items prior to the thresholds specified in TR 5-99 of PSM 
1-7-2. Thereafter, repeat the inspection at the intervals specified 
in TR 5-99 of PSM 1-7-2.
    (1) For airplanes that have accumulated 38,000 or more total 
flight cycles as of the effective date of this AD: Incorporate 
within 2,000 flight cycles after the effective date of this AD.
    (2) For airplanes that have accumulated less than 38,000 total 
flight cycles as of the effective date of this AD: Incorporate prior 
to the accumulation of 40,000 total flight cycles.
    (d) Incorporate into the FAA-approved maintenance inspection 
program the inspections and inspection intervals as defined in the 
DHC-7 Maintenance Manual, Chapter 5, Section 5-60-00, (PSM 1-7-2), 
Supplementary Inspection Program (SIP), Temporary Revision TR 5-97, 
dated December 22, 1997, at the applicable time specified in 
paragraph (d)(1) or (d)(2) of this AD; and inspect the significant 
structural items prior to the thresholds specified in TR 5-97 of PSM 
1-7-2. Thereafter, repeat the inspection at the intervals specified 
in TR 5-99 of PSM 1-7-2.
    (1) For airplanes that have accumulated 19,000 or more total 
flight cycles as of the effective date of this AD: Incorporate 
within 1,000 flight cycles after the effective date of this AD.
    (2) For airplanes that have accumulated less than 19,000 total 
flight cycles as of the effective date of this AD: Incorporate prior 
to the accumulation of 20,000 total flight cycles.
    (e) All inspection results, positive or negative, must be 
reported to de Havilland in accordance with ``Introduction,'' 
paragraph 5, of DHC-7 Maintenance Manual (PSM 1-7-2), Chapter 5, 
Section 5-60-00, Temporary Revision (TR 5-84), dated June 15, 1994. 
Information collection requirements contained in this regulation 
have been approved by the Office of Management and Budget (OMB) 
under the provisions of the Paperwork Reduction Act of 1980 (44 
U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-
0056.
    (f) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.

    (g) 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 3: The subject of this AD is addressed in Canadian 
airworthiness directive CF-94-19R1, dated January 26, 1998.

    Issued in Renton, Washington, on August 28, 1998.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-23743 Filed 9-2-98; 8:45 am]
BILLING CODE 4910-13-M