[Federal Register Volume 64, Number 224 (Monday, November 22, 1999)]
[Proposed Rules]
[Pages 63760-63762]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-30369]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-107-AD]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model DHC-7-100 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 all Bombardier Model DHC-7-100 
series airplanes. This proposal would require repetitive high frequency 
eddy current inspections to detect cracks on the locking pin fittings 
of the baggage door and locking pin housings of the fuselage; 
repetitive detailed visual inspections to detect cracks of the inner 
door structure on all four door locking attachment fittings; and 
corrective actions, if necessary. In lieu of accomplishing the 
corrective actions, this proposal also would provide a temporary 
option, for certain cases, for revising the Airplane Flight Manual 
(AFM), and installing a placard. 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 of the baggage door 
fittings and the support structure, which could result in structural 
failure, and consequent rapid decompression of the airplane during 
flight.

DATES: Comments must be received by December 22, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-107-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 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: Franco Pieri, 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) 256-7526; 
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 99-NM-107-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. 99-NM-107-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    Transport Canada Civil Aviation (TCCA), which is the airworthiness 
authority for Canada, notified the FAA that an unsafe condition may 
exist on all Bombardier Model DHC-7-100 series airplanes. TCCA advises 
that fatigue cracks have been reported in the door stop fittings 
mounted on the baggage door. Failure of a door stop fitting would 
appreciably degrade the structural integrity of the baggage door 
installation. This condition, if not corrected, could result in 
structural failure, and consequent rapid decompression of the airplane 
during flight.

Explanation of Relevant Service Information

    Bombardier has issued de Havilland Temporary Revision (TR) 5-100, 
dated
    December 23, 1998, for Supplementary Inspection Task 52-1 to the de 
Havilland Dash 7 Maintenance Manual PSM 1-7-2. The service information 
describes procedures for repetitive high frequency eddy current 
inspections to detect cracks on the locking pin fittings of the baggage 
door and locking pin housings of the fuselage; and repetitive detailed 
visual inspections to detect cracks of the inner door structure on all 
four door locking attachment fittings. TCCA classified this service 
information as mandatory and issued Canadian airworthiness directive 
CF-99-03, dated February 22, 1999, 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 
Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the 
applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, TCCA has kept the FAA informed of 
the situation described above. The FAA has examined the findings of 
TCCA, 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 States, the proposed AD would require accomplishment of 
the actions specified in the service information described previously, 
except as discussed below. The proposed AD also would require 
corrective actions to be accomplished in accordance with de Havilland 
Dash 7 Maintenance Manual PSM 1-7-2. The corrective actions, for 
certain cases, involve replacement of any cracked fitting or housing 
with a new fitting or housing, as applicable. For certain other

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cases, the corrective actions involve replacement of any cracked 
structure with a new support structure, or repair as described below. 
In lieu of accomplishing the corrective actions, this proposal also 
would provide a temporary option, for certain cases, for revising the 
Airplane Flight Manual (AFM), and installing a placard.

Differences Between Proposed Rule and Service Information

    Operators should note that, although the service information 
specifies that the manufacturer may be contacted for disposition of 
certain cracks, this proposal would require the repair of those 
conditions to be accomplished in accordance with a method approved by 
either the FAA, or the TCCA (or its delegated agent). In light of the 
type of repair that would be required to address the identified unsafe 
condition, and in consonance with existing bilateral airworthiness 
agreements, the FAA has determined that, for this proposed AD, a repair 
approved by either the FAA or the TCCA would be acceptable for 
compliance with this proposed AD.

Interim Action

    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.

Cost Impact

    The FAA estimates that 32 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 3 work 
hours per airplane to accomplish the proposed inspections, 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 
$5,760, or $180 per airplane, per inspection cycle.
    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:

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket 99-NM-107-AD.

    Applicability: All Model DHC-7-100 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 (d) 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 detect and correct fatigue cracking in the baggage door 
fittings and the support structure, which could result in structural 
failure, and consequent rapid decompression of the airplane during 
flight, accomplish the following:

Repetitive Inspections

    (a) At the latest of the times specified in paragraphs (a)(1) 
and (a)(2) of this AD, perform a high frequency eddy current 
inspection to detect fatigue cracks of the locking pin fittings of 
the baggage door and locking pin housings of the fuselage; and a 
detailed visual inspection to detect fatigue cracks of the inner 
door structure on all four locking attachment fittings of the 
baggage door; in accordance with de Havilland Temporary Revision 
(TR) 5-100, dated December 23, 1998, for Supplementary Inspection 
Task 52-1 to the de Havilland Dash 7 Maintenance Manual PSM 1-7-2. 
Thereafter, repeat the inspections at intervals not to exceed 1,000 
flight cycles.
    (1) Inspect prior to the accumulation of 12,000 total flight 
cycles.
    (2) Inspect within 600 flight cycles or 3 months after the 
effective date of this AD, whichever occurs later.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

Corrective Actions

    (b) If any crack is detected during any inspection required by 
paragraph (a) of this AD, prior to further flight, accomplish the 
requirements of paragraphs (b)(1) and (b)(2) of this AD, as 
applicable, except as provided in paragraph (c) of this AD. For 
operators that elect to accomplish the actions specified in 
paragraph (c) of this AD: After accomplishment of the replacement 
required by paragraph (b)(1) or (b)(2) of this AD, the AFM revision 
and placard required by paragraph (c) of this AD may be removed.
    (1) If a crack is detected in a baggage door locking pin fitting 
or fuselage locking pin housing: Replace the fitting or housing with 
a new fitting or housing, as applicable, in accordance with de 
Havilland Dash 7 Maintenance Manual PSM 1-7-2.
    (2) If a crack is detected in the inner baggage door structure 
at the locking attachment fittings: Replace the structure with a new 
support structure in accordance with de Havilland Dash 7 Maintenance 
Manual PSM 1-7-2, or repair in accordance with a method approved by 
the Manager, New York Aircraft Certification Office (ACO), FAA, 
Engine and Propeller Directorate, or the Transport Canada Civil 
Aviation (or its delegated agent). For a repair method to be 
approved by the Manager, New York ACO, as required by this 
paragraph, the Manager's approval letter must specifically reference 
this AD.
    (c) For airplanes on which only one baggage door stop fitting or 
its support structure is found cracked at one location, and on which 
the pressurization system ``Dump'' function is operational: Prior to 
further flight, accomplish the requirements of paragraphs (c)(1) and 
(c)(2) of this AD.

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Within 1,000 flight cycles after accomplishment of the requirements 
of paragraphs (c)(1) and (c)(2) of this AD, accomplish the 
requirements of paragraph (b)(1) or (b)(2) of this AD, as 
applicable.
    (1) Revise the Limitations Section of the FAA-approved DHC-7 
Airplane Flight Manual (AFM), PSM 1-71A-1A, to include the following 
statement. This AFM revision may be accomplished by inserting a copy 
of this AD into the AFM.
    Flight is restricted to unpressurized flight below 10,000 feet 
mean sea level (MSL). The airplane must be operated in accordance 
with DHC-7 AFM, PSM 1-71A-1A, Supplement 20.
    (2) Install a placard on the cabin pressure control panel or in 
a prominent location that states the following:
    DO NOT PRESSURIZE THE AIRCRAFT UNPRESSURIZED FLIGHT PERMITTED 
ONLY IN ACCORDANCE WITH DHC-7 AFM PSM 1-71A-1A, SUPPLEMENT 20 FLIGHT 
ALTITUDE LIMITED TO 10,000 FEET MSL OR LESS.

Alternative Methods of Compliance

    (d) 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. 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.

Special Flight Permits

    (e) Special flight permits may be issued in accordance with 
Secs. 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 4: The subject of this AD is addressed in Canadian 
airworthiness directive CF-99-03, dated February 22, 1999.

    Issued in Renton, Washington, on November 16, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-30369 Filed 11-19-99; 8:45 am]
BILLING CODE 4910-13-U