[Federal Register Volume 59, Number 2 (Tuesday, January 4, 1994)]
[Proposed Rules]
[Pages 266-268]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-22]


[[Page Unknown]]

[Federal Register: January 4, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 92-NM-157-AD]

 

Airworthiness Directives; de Havilland, Inc., Model DHC-7 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to certain de Havilland Model DHC-7 series 
airplanes, that would have required a one-time inspection to assess the 
adequacy of the clearance between various adapter plates and seal 
retaining angles on the fuselage side access panel, and modification, 
if necessary. That proposal was prompted by reports of incidents 
involving corrosion and fatigue cracking in commuter-class airplanes 
that are approaching or have exceeded their economic design goal. This 
action revises the proposed rule by requiring modification of both the 
forward and rear seal retention angles, regardless of whether damage is 
found. The actions specified by this proposed AD are intended to 
prevent degradation of the structural capabilities of the affected 
airplanes.

DATES: Comments must be received by February 13, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 92-NM-157-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from de Havilland, Inc., 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 
FAA, Engine and Propeller Directorate, New York Aircraft Certification 
Office, 181 South Franklin Avenue, room 202, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT:
Sol Maroof, Aerospace Engineer, Airframe Branch, ANE-172, FAA, New York 
Aircraft Certification Office, 181 South Franklin Avenue, room 202, 
Valley Stream, New York 11581; telephone (516) 791-6220; fax (516) 791-
9024.

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 92-NM-157-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. 92-NM-157-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations to 
add an airworthiness directive (AD), applicable to certain de Havilland 
Model DHC-7 series airplanes, was published as a notice of proposed 
rulemaking (NPRM) in the Federal Register on March 4, 1993 (58 FR 
12349). That NPRM would have required a one-time inspection to assess 
the adequacy of the clearance between: (1) The wing forward pick-up 
adapter plate and the seal retaining angle on the fuselage side access 
panel, and (2) the wing rear mounting adapter plates and the seal 
retaining angle on the fuselage side access panel; and modification, if 
necessary. That NPRM was prompted by reports of incidents involving 
corrosion and fatigue cracking in commuter-class airplanes that are 
approaching or have exceeded their economic design goal. That 
condition, if not corrected, could result in degradation of the 
structural capabilities of the affected airplanes.
    Since the issuance of that NPRM, the FAA has received a comment 
that has caused the FAA to reconsider its position on certain aspects 
of the proposed rule.
    The commenter requests that the proposal be revised to require 
modification of the forward and rear retention angles and adapter 
plates, regardless of whether damage is found in the adapter plates. 
The commenter contends that if the forward and rear seal retainers are 
not trimmed, they may be inadvertently interchanged with seal retainers 
from other airplanes in an operator's fleet. The FAA concurs. The FAA 
has reviewed all available data and has determined that in order to 
preclude the possibility for installing an untrimmed seal retainer in 
an airplane that lacks sufficient clearance, the forward and rear seal 
retainers must be trimmed. Although the referenced service bulletins do 
not specify trimming the forward and rear seal retainers when the seal 
retainers are found undamaged, the FAA finds that safety can be best 
assured when the seal retainers are trimmed, regardless of whether 
damage is found, to avoid the possibility for inadvertently 
interchanging seal retainers from other airplanes. Therefore, proposed 
paragraph (a) of the previously issued NPRM has been revised to propose 
requiring that Modification 7/2319 (forward adapter plates and seal 
retaining angle), and paragraph (b) of the NPRM has been revised to 
propose requiring that Modification 7/2355 (rear adapter plates and 
seal retaining angle) be accomplished.
    Further, this commenter indicates that the proposed 6-month 
compliance time to accomplish the inspection was unnecessarily 
stringent in light of the age of the service bulletins. From this 
comment, the FAA infers that the commenter requests an extension to the 
compliance time, although the commenter does not specify an 
alternative. The FAA concurs that the compliance time may be extended 
somewhat. The FAA has determined that extending the compliance time by 
6 additional months will not adversely affect safety, and will allow 
the inspection to be performed at a base during regularly scheduled 
maintenance where special equipment and trained maintenance personnel 
will be available. It will also provide additional time to accomplish 
the additional modification proposed in this action. Therefore, 
paragraphs (a) and (b) of this supplemental NPRM have been revised to 
require that the inspection be accomplished within 12 months.
    Since certain of these changes expand the scope of the originally 
proposed rule, the FAA has determined that it is necessary to reopen 
the comment period to provide additional opportunity for public 
comment.
    The FAA estimates that 44 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 modifications and inspections, and 
that the average labor rate is $55 per work hour. Required parts would 
be nominal in cost. Based on these figures, the total cost impact of 
the proposed AD on U.S. operators is estimated to be $19,360, or $440 
per airplane. This total cost figure assumes that no operator has yet 
accomplished the proposed requirements of this AD action.
    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 14 
CFR part 39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

De Havilland, Inc.: Docket 92-NM-157-AD.

    Applicability: Model DHC-7 airplanes having serial numbers 1 
through 99 inclusive, certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent structural failure, accomplish the following:
    (a) For airplanes having serial numbers 1 through 77 inclusive, 
79 through 83 inclusive, 85, and 86: Within 12 months after the 
effective date of this AD, inspect the clearance between the wing 
forward pick-up adapter plates and the seal retaining angle on the 
fuselage side access panel in accordance with de Havilland Service 
Bulletin 7-57-11, dated December 17, 1982.
    (1) If the adapter plates are undamaged or if scoring on the 
adapter plates does not exceed 0.050 inch in depth, prior to further 
flight, accomplish Modification 7/2319 in accordance with the 
service bulletin.
    (2) If scoring on the adapter plates is equal to or exceeds 
0.050 inch in depth, prior to further flight, repair in accordance 
with a method approved by the Manager, New York Aircraft 
Certification Office (ACO), ANE-170, FAA, Engine and Propeller 
Directorate.
    (b) For airplanes having serial numbers 1 through 99, inclusive: 
Within 12 months after the effective date of this AD, inspect the 
clearance between the rear mounting adapter plates and the seal 
retaining angle on the fuselage side access panel in accordance with 
de Havilland Service Bulletin 7-57-19, dated February 24, 1984.
    (1) If the adapter plates are undamaged or if scoring on the 
adapter plates does not exceed 0.050 inch in depth, prior to further 
flight, accomplish Modification 7/2355 in accordance with the 
service bulletin.
    (2) If scoring on the adapter plates is equal to or exceeds 
0.050 inch in depth, prior to further flight, repair in accordance 
with a method approved by the Manager, New York ACO, ANE-170, FAA, 
Engine and Propeller Directorate.
    (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 York ACO, ANE-170, 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: 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 FAR 
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 December 28, 1993.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-22 Filed 1-3-94; 8:45 am]
BILLING CODE 4910-13-P