[Federal Register Volume 61, Number 170 (Friday, August 30, 1996)]
[Proposed Rules]
[Pages 45914-45916]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-22143]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-163-AD]
RIN 2120-AA64


Airworthiness Directives; de Havilland Model DHC-8-102 and -103 
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 de Havilland Model DHC-8-
102 and -103 series airplanes. This proposal would require repetitive 
external inspections to detect cracks in the skin exterior of the 
fuselage at floor level, and repair, if necessary. This proposal also 
would require repetitive internal inspections to detect cracks of the 
subject area, which terminates the repetitive external inspections. 
This proposal is prompted by a report that one of the tasks in the 
Maintenance Program Airworthiness Limitations List inadvertently 
excluded certain airplanes from the instructions for the inspections. 
The actions specified by the proposed AD are intended to prevent 
undetected cracking of the frames and skin panels of the fuselage, 
which could result in reduced structural integrity of the airplane.

DATES: Comments must be received by October 8, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-163-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.

FOR FURTHER INFORMATION CONTACT: Jon Hjelm, Aerospace Engineer, Systems 
and Equipment Branch, ANE-172, FAA, New York Aircraft Certification 
Office, Engine and Propeller Directorate, 10 Fifth Street, Third Floor, 
Valley Stream, New York 11581; telephone (516) 256-7523; 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 95-NM-163-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-103, Attention: Rules 
Docket No. 95-NM-163-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    Transport Canada Aviation, which is the airworthiness authority for 
Canada, has notified the FAA that an unsafe condition may exist on 
certain de Havilland Model DHC-8-102 and -103 series airplanes. 
Transport Canada advises that, in a previous issue of the Maintenance 
Program Airworthiness Limitations List (ALL), certain modified 
airplanes were inadvertently excluded from instructions for performing 
one of the required maintenance tasks.
    The ALL contains mandatory damage tolerance inspections of the 
fuselage [required by section 25.571 (``Damage tolerance and fatigue 
evaluation of structure'') of the Federal Aviation Regulations (14 CFR 
25.571), amendment 25-45] that are part of the type certificate of 
these airplanes. The instructions for these inspections are in the form 
of inspection ``maintenance task cards'' and are contained in the Dash 
8 Maintenance Program Manual PSM 1-8-7.
    Maintenance Task Card 5310/30C contains instructions for performing 
internal visual inspections to detect cracks of the left- and right-
hand fuselage frames at the floor level. It also contains an 
effectivity listing, which specifies those airplanes on which the 
inspection is necessary. The effectivity of this task card lists 
airplanes on which de Havilland Modification 8/0427 has not been 
installed, but inadvertently

[[Page 45915]]

excludes from the list the airplanes on which that modification has 
been installed. Both the modified and unmodified airplanes must receive 
these inspections, however.
    Since the ALL is incorporated into the Dash 8 Maintenance Program 
Manual, and since the ALL's effectivity for this necessary inspection 
is incorrect, the fuselage frames of the modified airplanes may not 
have been inspected. Without these necessary inspections, cracking 
could occur and go undetected. Additionally, cracking of the fuselage 
frames is often associated with secondary cracking of the fuselage 
skin. Such cracking of the frames and skin panels of the fuselage at 
the floor level, if not detected and corrected, could result in reduced 
structural integrity of the airplane.

Explanation of Relevant Service Information

    De Havilland has issued Service Bulletin 8-53-48, dated August 26, 
1994, which describes procedures for repetitive external detailed 
visual inspections to detect cracks in the left-and right-hand skin 
exterior of the fuselage at the floor level on Model DHC-8 series 
airplanes on which de Havilland Modification 8/0427 has been installed. 
The service bulletin also describes procedures for repetitive internal 
visual inspections to detect cracks of the fuselage frames. 
Accomplishment of the internal inspection eliminates the need for the 
repetitive external inspections. In addition, the service bulletin 
describes procedures for reporting all cracks to Bombardier Regional 
Aircraft Division.
    Transport Canada Aviation classified this service bulletin as 
mandatory and issued Canadian airworthiness directive CF-94-17, dated 
September 9, 1994, in order to assure the continued airworthiness of 
these airplanes in Canada.

FAA's Conclusion

    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, Transport Canada Aviation has kept 
the FAA informed of the situation described above. The FAA has examined 
the findings of Transport Canada Aviation, 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, the 
proposed AD would require repetitive external detailed visual 
inspections to detect cracks in the left-and right-hand skin exterior 
of the fuselage at the floor level. The proposed AD also would require 
repetitive internal visual inspections to detect cracks of the fuselage 
frames; initiation of these inspections would constitute terminating 
action for the repetitive external inspection requirements. The actions 
would be required to be accomplished in accordance with the service 
bulletin described previously.
    This proposed AD would be applicable only to airplanes on which de 
Havilland Modification 8/0427 has been installed, and on which 
Maintenance Program Manual PSM 1-8-7, Task 5310/30C (Section 3-53, page 
12, dated August 10, 1993) has not been accomplished.

Differences Between the Proposal and the Related Service 
Information

    Operators should note that, although the service bulletin specifies 
that operators are to contact Bombardier Regional Aircraft Division for 
``disposition of all cracks,'' this proposed AD would require that 
operators accomplish the repair of any cracking in accordance with the 
de Havilland DHC-8 Structural Repair Manual, or in accordance with a 
method approved by Transport Canada Aviation or the FAA.

Cost Impact

    The FAA estimates that 80 airplanes of U.S. registry would be 
affected by this proposed AD.
    The proposed external inspections would take approximately 1 work 
hour per airplane to accomplish, at an average labor rate of $60 per 
work hour. Based on these figures, the cost impact of the proposed AD 
on U.S. operators is estimated to be $4,800, or $60 per airplane, per 
inspection.
    The proposed internal inspections 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 the proposed AD 
on U.S. operators is estimated to be $14,400, or $180 per airplane, per 
inspection.
    The cost impact figures discussed above are 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:

de Havilland, Inc.: Docket 95-NM-163 AD.

    Applicability: Model DHC-8-102 and 103 series airplanes having 
serial numbers 101 through 180, inclusive; on which de Havilland 
Modification 8/0427 has been installed, and on which Maintenance 
Program Manual PSM 1-8-7, Task 5310/30C (Section 3-53, page 12, 
dated August 10, 1993) has not been accomplished; certificated in 
any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability

[[Page 45916]]

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 (c) 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 undetected cracking of the frames and skin panels of 
the fuselage, which could result in reduced structural integrity of 
the airplane, accomplish the following:
    (a) Prior to the accumulation of 15,343 total flight cycles, or 
within 200 landings after the effective date of this AD, whichever 
occurs later, perform an external detailed visual inspection to 
detect cracks in the left- and right-hand skin exterior of the 
fuselage at floor level, in accordance with paragraph III, External 
Inspection, of the Accomplishment Instructions of de Havilland 
Service Bulletin S.B. 8-53-48, dated August 26, 1994.
    (1) If no crack is detected, repeat the external detailed visual 
inspection thereafter at intervals not to exceed 750 landings.
    (2) If any crack is detected, prior to further flight, perform 
an internal visual inspection to detect cracks of the fuselage 
frames in accordance with the service bulletin. Accomplishment of 
this internal visual inspection constitutes terminating action for 
the repetitive external detailed visual inspections required by of 
paragraph (a)(1) of this AD.
    (i) If no crack is detected during the internal inspection, 
prior to further flight, repair the cracked area(s) found during the 
external inspection, in accordance with the de Havilland DHC-8 
Structural Repair Manual; or in accordance with a method approved by 
Transport Canada; or in accordance with a method approved by the 
Manager, New York Aircraft Certification Office (ACO), FAA, Engine 
and Propeller Directorate. Repeat the internal inspection thereafter 
at intervals specified in accordance with the Dash 8 Maintenance 
Program Manual.
    (ii) If any crack is detected during the internal inspection, 
prior to further flight, repair all cracks found during both the 
external and internal inspections, in accordance with the de 
Havilland DHC-8 Structural Repair Manual, or in accordance with a 
method approved by Transport Canada Aviation; or in accordance with 
a method approved by the Manager, New York ACO, FAA, Engine and 
Propeller Directorate. Repeat the internal inspection thereafter at 
intervals specified in accordance with the Dash 8 Maintenance 
Program Manual.
    (b) Prior to the accumulation of 31,000 flight cycles, or within 
12 months after the effective date of this AD, whichever occurs 
later, perform an internal visual inspection to detect cracking of 
the fuselage frames, in accordance with de Havilland Service 
Bulletin S.B. 8-53-48, dated August 26, 1994. Accomplishment of the 
internal visual inspection constitutes terminating action for the 
repetitive external detailed visual inspections required by 
paragraph (a)(1) of this AD.
    (1) If no cracking is detected during the internal inspection, 
repeat the internal inspection thereafter at intervals specified in 
accordance with the Dash 8 Maintenance Program Manual.
    (2) If any cracking is detected during the internal inspection, 
prior to further flight, repair it in accordance with the de 
Havilland DHC-8 Structural Repair Manual, or in accordance with a 
method approved by Transport Canada Aviation; or in accordance with 
a method approved by the Manager, New York ACO, FAA, Engine and 
Propeller Directorate. Repeat the internal inspection thereafter at 
intervals specified in accordance with the Dash 8 Maintenance 
Program Manual.
    (c) 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 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.

    (d) 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.

    Issued in Renton, Washington, on August 23, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-22143 Filed 8-29-96; 8:45 am]
BILLING CODE 4910-13-P