[Federal Register Volume 61, Number 190 (Monday, September 30, 1996)]
[Proposed Rules]
[Pages 51062-51064]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-24890]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-265-AD]
RIN 2120-AA64
Airworthiness Directives; de Havilland Model DHC-7 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
-----------------------------------------------------------------------
SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to all de Havilland Model DHC-7
series airplanes. This proposal would require performing a review of
the airplane maintenance records to determine if any insulation
blankets have been repaired or changed during service, and various
follow- on actions, if necessary. This proposal is prompted by reports
of corrosion forming on areas of the airplane structure where black
film thermal insulation blankets are used. The actions specified by the
proposed AD are intended to prevent such corrosion, which could result
in degradation of the structural capability of the airplane fuselage
and consequent sudden loss of cabin pressure.
DATES: Comments must be received by November 8, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-265-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: Sol Maroof, Aerospace Engineer,
Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft
Certification Office, Engine and Propeller Directorate, 10 Fifth
Street, Third Floor, Valley Stream, New York 11581; telephone (516)
256-7522; 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-265-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-265-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
Transport Canada Aviation, which is the airworthiness authority for
Canada, recently notified the FAA that an unsafe condition may exist on
all de Havilland Model DHC-7 series airplanes. Transport Canada advises
that it has received reports of corrosion forming on areas of the
airplane structure where black Orcon film covers the thermal insulation
blankets. Investigation revealed that the black Orcon film, used to
insulate the airplane, contains carbon. The cause of this corrosion has
been attributed to the formation of condensation on aluminum airplane
structure where the structure comes in contact with the carbon in the
black Orcon film. Such corrosion, if not detected and corrected in a
timely manner, could result in degradation of the strength of the
airplane fuselage structure and, consequently, could lead to sudden
loss of cabin pressure.
[[Page 51063]]
Explanation of Relevant Service Information
Bombardier has issued Service Bulletin S.B. 7-21-30, dated July 6,
1994, which describes procedures for performing the following:
1. A review of the airplane maintenance records to determine if any
insulation blankets have been repaired or changed during service;
2. A visual inspection to detect black film insulation of the air
conditioning system, if any insulation has been repaired or changed
during service, or if a certain kit is installed;
3. A review of the airplane modification records to determine if
certain kits have been installed, if no black film insulation is
detected; and
4. Various follow-on actions, if any black film insulation is
detected. (The follow-on actions include removal of any black film
insulation, an inspection to detect corrosion, repair of any corroded
structure, and installation of new silver blankets.)
Transport Canada Aviation classified this service bulletin as
mandatory and issued Canadian airworthiness directive CF-94-24, dated
December 22, 1994, 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, 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 performing a review of the airplane
maintenance records to determine if any insulation blankets have been
repaired or changed during service, and various follow-on actions, if
necessary. The actions would be required to be accomplished in
accordance with the service bulletin described previously. The repair
of any corroded structure would be required to be accomplished in
accordance with a method approved by the FAA.
Other Relevant Rulemaking
The FAA previously issued a proposed AD that is similar to this
action. That proposed AD [reference Docket 84-NM-89-AD (61 FR 13785,
March 28, 1996)] is applicable to de Havilland Model DHC-8 series
airplanes and would require actions similar to those proposed in this
notice.
Cost Impact
The FAA estimates that 50 de Havilland Model DHC-7 series airplanes
of U.S. registry would be affected by this proposed AD, that it would
take approximately 1 work hour per airplane to accomplish the proposed
actions, 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 $3,000, or $60 per airplane.
The cost impact figure discussed above is 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-265-AD.
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
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 use the authority
provided in paragraph (e) of this AD to request approval from the
FAA. This approval may address either no action, if the current
configuration eliminates the unsafe condition; or different actions
necessary to address the unsafe condition described in this AD. Such
a request should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent degradation of the structural capability of the
fuselage and sudden loss of cabin pressure, accomplish the
following:
(a) Within six months after the effective date of this AD,
perform a review of the airplane maintenance records to determine if
any insulation blankets have been repaired or changed during
service, in accordance with de Havilland Service Bulletin S.B. 7-21-
30, dated July 6, 1994.
(b) If no insulation blanket has been repaired or changed, no
further action is required by this AD.
(c) If any insulation blanket has been repaired or changed,
prior to further flight, perform a visual inspection to detect black
film insulation of the air conditioning system, in accordance with
de Havilland Service Bulletin S.B. 7-21-30, dated July 6, 1994.
(1) If no black film insulation is detected, prior to further
flight, perform a review of the airplane modification records to
determine if any kit listed in ``Table 1--Modification List'' has
been installed, in accordance with the service bulletin.
[[Page 51064]]
(i) If no kit listed in Table 1--Modification List is found to
be installed, no further action is required by this AD.
(ii) If any kit listed in Table 1 is found to be installed,
prior to further flight, perform the various follow-on actions in
accordance with the service bulletin. (The follow-on actions include
an inspection to detect black film insulation, removal of any black
film insulation, an inspection to detect corrosion, repair of
corroded structure, and installation of new silver blankets.)
However, in lieu of repairing corroded structure in accordance with
service bulletin, the repair of any corrosion shall be done in
accordance with a method approved by the Manager, New York Aircraft
Certification Office (ACO), FAA, Engine and Propeller Directorate.
(2) If any black film insulation is detected, prior to further
flight, perform the follow-on actions in accordance with the service
bulletin. (The follow-on actions include removal of any black film
insulation, an inspection to detect corrosion, repair of any
corroded structure, and installation of new silver blankets.)
However, in lieu of repairing corroded structure in accordance with
service bulletin, the repair of any corrosion shall be done in
accordance with a method approved by the Manager, New York ACO.
(d) As of the effective date of this AD, no person shall install
black Orcon film insulation, part number AN46B/AN36B, on any
airplane.
(e) 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, 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.
(f) 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 September 23, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-24890 Filed 9-27-96; 8:45 am]
BILLING CODE 4910-13-U
