[Federal Register Volume 65, Number 8 (Wednesday, January 12, 2000)]
[Rules and Regulations]
[Pages 1765-1767]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-499]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-357-AD; Amendment 39-11504; AD 2000-01-07]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model DHC-8-100, -200, and -
300 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Bombardier Model DHC-8-100, -200, and -300 
series airplanes. This action requires the removal and testing of 
sections of bonded skin from the upper and lower skin panels of the 
horizontal stabilizer, repair of those areas, and follow-on corrective 
actions, if necessary. This amendment is prompted by issuance of 
mandatory continuing airworthiness information by a foreign civil 
airworthiness authority. The actions specified in this AD are intended 
to prevent reduced strength capability and consequent failure of the 
horizontal stabilizer, which could result in loss of controllability of 
the airplane.

DATES: Effective January 27, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 27, 2000.
    Comments for inclusion in the Rules Docket must be received on or 
before February 11, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-357-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    The service information referenced in this AD 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; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Serge Napoleon, 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) 256-7512; 
fax (516) 568-2716.

SUPPLEMENTARY INFORMATION: Transport Canada Civil Aviation (TCCA), 
which is the airworthiness authority for Canada, notified the FAA that 
an unsafe condition may exist on certain Bombardier Model DHC-8-100, -
200, and -300 series airplanes. TCCA advises that it received results 
of previous inspections to detect disbonding of the upper and lower 
skin panels of the horizontal stabilizer. Results of these inspections 
indicate that certain doublers and stringers were disbonded from their 
skin panels. The subject doublers and stringers are installed on the 
upper and lower skin panels of the horizontal stabilizer at stations 
Yh6.15-139.00 between the front spar and rear spar. The cause of such 
disbonding has been attributed to an improper bonding process of the 
skin panels of the doublers and stringers during manufacturing. This 
condition, if not corrected, could result in reduced strength 
capability and consequent failure of horizontal stabilizer, which could 
further result in loss of controllability of the airplane.
    TCCA has recommended further testing on sample coupons of the 
sections of skin panels to determine the bonding integrity of the skin 
panels. A destructive peel test would be conducted on the removed 
sections of bonded skin (test coupons) by the manufacturer. This type 
of testing would determine how much force is necessary in order to 
separate the bonded layers of the skin panel.

Explanation of Relevant Service Information

    The manufacturer has issued Bombardier Service Bulletin S.B. 8-55-
24, dated February 26, 1998, which describes procedures for replacement 
of the horizontal stabilizer with a new horizontal stabilizer.
    Accomplishment of the test on the sample coupons and, if necessary, 
accomplishment of the actions specified in the service bulletin is 
intended to adequately address the identified unsafe condition. TCCA 
approved this service bulletin and issued Canadian airworthiness 
directive CF-99-15R1, dated December 6, 1999, in order to assure the 
continued airworthiness of these airplanes in Canada.

Related Rulemaking

    On November 16, 1998, the FAA issued AD 98-24-18, amendment 39-
10903 (63 FR 64609, November 23, 1998), applicable to certain 
Bombardier Model DHC-8-100 and -300 series airplanes equipped with 
Canadian Aviation Products (CAP) horizontal stabilizers having serial 
numbers 003 through 214, that requires repetitive ultrasonic 
inspections to detect disbonding of the upper and lower skin panels of 
the horizontal stabilizer, and repair, if necessary. Based on the 
information provided by TCCA, the FAA has determined that an additional 
disbonding test of the skin panels is needed on airplanes equipped with 
CAP horizontal stabilizers having serial numbers 003 through 050, the 
repetitive ultrasonic inspections required by AD 98-24-18 may not be 
adequate to detect disbonding of the upper and lower skin panels of the 
horizontal stabilizer, and, therefore, may not be providing an adequate 
level of safety for the transport airplane fleet. This AD affects the 
requirements of that AD. For certain airplanes, the corrective actions 
of this AD eliminate the need for the repetitive inspections required 
by AD 98-24-18.

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, 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 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, this AD is being issued to prevent reduced 
strength capability of the horizontal stabilizer and consequent failure 
of the horizontal stabilizer,

[[Page 1766]]

which could result in loss of controllability of the airplane. This AD 
requires removal and testing of the sections of bonded skin from the 
upper and lower skin panels of the horizontal stabilizer, repair of 
those areas, and follow-on corrective actions, if necessary. Certain 
actions (removal and repair) are required to be accomplished in 
accordance with a method approved by the Manager, FAA, Engine and 
Propeller Directorate, New York Aircraft Certification Office (ACO). 
Other actions (replacement) are required to be accomplished in 
accordance with the service bulletin described previously.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NM-357-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will not have a substantial direct 
effect 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, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:
2000-01-07 Bombardier, INC. (Formerly de Havilland, Inc.): Amendment 
39-11504. Docket 99-NM-357-AD.


    Applicability: Model DHC-8-100, -200, and -300 series airplanes, 
certificated in any category; equipped with Canadian Aviation 
Products (CAP) horizontal stabilizers having serial numbers CAP 003 
through CAP 050 inclusive.

    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 prevent reduced strength capability of the horizontal 
stabilizer and consequent failure of the horizontal stabilizer, 
which could result in loss of controllability of the airplane, 
accomplish the following:

Removal of Skin Sections

    (a) Within 2 months after the effective date of this AD, 
accomplish the requirements of paragraphs (a)(1), (a)(2), and (a)(3) 
of this AD.
    (1) Remove sections of bonded skin (test coupons) from the upper 
panel P/N 85510026, and the lower skin panel P/N 85510025, of the 
horizontal stabilizer port and starboard side, at stations Yh77.50-
90.90 between stringer number 6 and the rear spar, in accordance 
with a method approved by the Manager, FAA, Engine and Propeller 
Directorate, New York Aircraft Certification Office (ACO); and
    (2) Mark and send for testing the removed sections of bonded 
skin to the attention of M. Elliott X3177 or M. Clark X3092, 
Bombardier Aerospace Mailroom (A.O.G.), 123 Garratt Boulevard, 
Downsview, Ontario, Canada, M3K-1Y5; and
    (3) Repair the areas where the sections of bonded skin were 
removed, in accordance with a method approved by the Manager, FAA, 
Engine and Propeller Directorate, New York Aircraft Certification 
Office (ACO). After the repair, the airplane may be returned to 
service while awaiting test results.

    Note 2: The Manager, FAA, Engine and Propeller Directorate, New 
York ACO, has approved Bombardier Repair Drawing RD8-55-669, Issue 
3, dated March 17, 1999, as an acceptable method for accomplishing 
the actions required by paragraph (a) of this AD. Operators should 
note that the repair drawing recommends a one-time ultrasonic 
inspection to detect disbonding on the stringers and doublers of the 
horizontal stabilizer. However, the approved method of compliance 
does not require the ultrasonic inspection.

Corrective Actions

    (b) Within 30 days following the removal of the sections of 
bonded skin (test coupons) from the upper and lower skin panels of 
the horizontal stabilizer, determine the test results and accomplish 
paragraph (b)(1) or (b)(2) of this AD, as applicable.
    (1) For airplanes on which all sections of bonded skin (test 
coupons) pass the test required by this AD, no further action is 
required by this AD.

[[Page 1767]]

    (2) For airplanes on which any section of bonded skin (test 
coupon) fails the test, prior to further flight, either replace the 
horizontal stabilizer with a new horizontal stabilizer in accordance 
with Bombardier Service Bulletin S.B. 8-55-24, dated February 26, 
1998, or repair in accordance with a method approved by the Manager, 
New York ACO.
    (c) Model DHC-8-100, -200, and -300 series airplanes, equipped 
with Canadian Aviation Products (CAP) horizontal stabilizers having 
serial numbers CAP 003 through CAP 050 inclusive: Passing the test 
on all sections of bonded skin constitutes terminating action for 
the repetitive inspections required by AD 98-24-18, amendment 39-
10903. Accomplishment of either the replacement or an approved 
repair, as required by paragraph (b)(2) of this AD, on any airplane 
on which any section of bonded skin fails the test also constitutes 
terminating action for the repetitive inspections required by AD 98-
24-18, amendment 39-10903.

    Note 3: Following accomplishment of the requirements of this AD, 
the horizontal stabilizer remains subject to the normal bonding 
integrity inspection program, which is performed in accordance with 
de Havilland Product Support Manual (PSM) 1-8-7.

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 4: 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 
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.

Incorporation by Reference

    (f) Except as provided by paragraphs (a)(1) and (a)(3) of this 
AD, the actions shall be done in accordance with Bombardier Service 
Bulletin S.B. 8-55-24, dated February 26, 1998, as applicable. This 
incorporation by reference was approved by the Director of the 
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. Copies may be obtained from Bombardier, Inc., Bombardier 
Regional Aircraft Division, Garratt Boulevard, Downsview, Ontario 
M3K 1Y5, Canada. Copies may be inspected 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; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.

    Note 5: The subject of this AD is addressed in Canadian 
airworthiness directive CF-99-15R1, dated December 6, 1999.

    (g) This amendment becomes effective on January 27, 2000.

    Issued in Renton, Washington, on January 4, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-499 Filed 1-11-00; 8:45 am]
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