[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]
-----------------------------------------------------------------------
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.
-----------------------------------------------------------------------
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