[Federal Register Volume 62, Number 137 (Thursday, July 17, 1997)]
[Rules and Regulations]
[Pages 38206-38208]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-18934]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-136-AD; Amendment 39-10082; AD 97-14-11]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model CL-600-2B19 (Regional 
Jet Series 100 and 200) Series Airplanes

agency: Federal Aviation Administration, DOT.

action: Final rule; request for comments.

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summary: This document publishes in the Federal Register an amendment 
adopting airworthiness directive (AD) 97-14-11 that was sent previously 
to all known U.S. owners and operators of certain Bombardier Model CL-
600-2B19 (Regional Jet Series 100 and 200) series airplanes by 
individual notices. This AD requires repetitive inspections to detect 
cracks of a certain bulkhead web of the fuselage at certain locations, 
and repair, if necessary. This action is prompted by a report of a 
pressurization problem during flight, which was caused by fatigue 
cracking in the underfloor pressure bulkhead of the fuselage. The 
actions specified by this AD are intended to detect and correct such 
fatigue cracking, which could result in uncontrolled depressurization 
of the airplane and/or reduced structural integrity of the fuselage.

dated: Effective July 22, 1997. To all persons except those persons to 
whom it was made immediately effective by emergency AD 97-14-11, issued 
on June 27, 1997, which contained the requirements of this amendment.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of Federal Register as of 
July 22, 1997.
    Comments for inclusion in the Rules Document must be received on or 
before September 15, 1997.

addresses: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-136-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    The applicable service information may be obtained from Bombardier, 
Inc., Canadair Aerospace Group, P.O. Box 6087, Station Centre-ville, 
Quebec H3C 3G9, 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 (ACO), 10 Fifth Street, Third Floor, 
Valley Stream, New York; or at the Office of the Federal Register, 800 
North Capital Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: George Duckett, Aerospace Engineer, or 
Franco Peiri, 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; telephone (516) 256-7525 or -7526; fax (516) 568-2716.

supplementary information: On June 27, 1997, the FAA issued emergency 
AD 97-14-11, which is applicable to certain Bombardier Model CL-600-
2B19 (Regional Jet Series 100 and 200) series airplanes. That action 
was prompted by a report of a pressurization problem during flight on a 
Model CL-600-2B19 series airplane. Investigation revealed a crack 
approximately 14 inches long in the center pressure bulkhead. In 
addition, such cracking was found on seven other Model CL-600-2B19 
series airplanes. The cause of this cracking has been attributed to 
structural fatigue. Fatigue cracking in the underfloor pressure 
bulkhead of the fuselage, if not detected and corrected in a timely 
manner, could result in uncontrolled depressurization of the airplane 
and/or reduced structural integrity of the fuselage.

Explanation of Relevant Service Information

    The manufacturer has issued Canadair Regional Jet Alert Service 
Bulletin A601R-53-045, dated June 25, 1997, which describes procedures 
for repetitive detailed visual inspections to detect cracks at FS 
409+128 of a certain bulkhead web of the fuselage at certain locations, 
and repair, if necessary. Transport Canada Aviation classified this 
alert service bulletin as mandatory and issued Canadian airworthiness 
directive CF-97-11, dated June 25, 1997, 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 the Requirements of the Rule

    Since the unsafe condition described is likely to exist or develop 
on other airplanes of the same type design registered in the United 
States, the FAA issued emergency AD 97-14-11 to require repetitive 
detailed visual inspections to detect cracks at FS 409+128 of a certain 
bulkhead web of the fuselage at certain locations, and repair, if 
necessary. This AD also requires that operators report the results of 
the detailed visual inspection to the FAA. The inspections are required 
to be accomplished in accordance with the alert service bulletin 
previously described. The repair is required to be accomplished in 
accordance with a method approved by the FAA.

[[Page 38207]]

    Operators should note that, while it is not the FAA's normal policy 
to allow flight with known cracks, this AD does permit further flight 
with cracking within certain limits. The results of a review, conducted 
by the manufacturer, revealed that cracking in the underfloor pressure 
bulkhead of the fuselage will not result in rapid decompression of the 
airplane. Therefore, according to the review, if the crack size limits 
are strictly observed and if repetitive inspections are performed at 
the required intervals, cracks that grow beyond the limits will be 
detected, and corrective action taken, before they can grow to a size 
that would create an unacceptable risk of structural failure. Transport 
Canada Aviation concurs with the findings of this review. In 
consideration of these findings and based on the FAA's criteria for 
flight with known cracking, the FAA has determined that further flight 
with cracking within certain limits in the center pressure bulkhead is 
permissible for an interim period.
    This is considered to be interim action. The manufacturer has 
advised that it currently is developing a modification that will 
positively address the unsafe condition addressed by this AD. Once this 
modification is developed, approved, and available, the FAA may 
consider additional rulemaking.
    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual notices 
issued on June 27, 1997, to all known U.S. owners and operators of 
certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 and 200) 
series airplanes. These conditions still exist, and the AD is hereby 
published in the Federal Register as an amendment to section 39.13 of 
the Federal Aviation Regulations (14 CFR 39.13) to make it effective as 
to all persons.

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 97-NM-136-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    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:

97-14-11 Bombardier, Inc. (Formerly Canadair): Amendment 39-10082. 
Docket 97-NM-136-AD.

    Applicability: Model CL-600-2B19 (Regional Jet Series 100 and 
200) series airplanes, serial numbers 7003 and subsequent; 
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 (c) 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 underfloor 
pressure bulkhead of the fuselage, which could result in 
uncontrolled depressurization of the airplane and/or reduced 
structural integrity of the fuselage, accomplish the following:
    (a) Within 20 flight hours after the effective date of this AD, 
perform a detailed visual inspection to detect cracks at frame 
station (FS) 409+128 of the bulkhead web [part number (P/N) 
601R32208-123] of the fuselage, in accordance with Canadair Regional 
Jet Alert Service Bulletin A601R-53-045, dated June 25, 1997.
    (1) If no crack is detected or if all three of the conditions 
specified in paragraphs (a)(1)(i), (a)(1)(ii), and (a)(1)(iii) of 
this AD are met, continued flight is allowed. Repeat the detailed 
visual inspection thereafter at intervals not to exceed 100 flight 
hours.
    (i) No more than one crack exists at each corner; and

[[Page 38208]]

    (ii) No crack extends under the angles having P/N 601R32208-79 
and P/N 601R32208-81 on the aft side of the bulkhead web; and
    (iii) No crack exists in angles having P/N 601R32208-79 and P/N 
601R32208-81 on the aft side of the bulkhead web.
    (2) If any cracking other than that identified in paragraphs 
(a)(1)(i), (a)(1)(ii), and (a)(1)(iii) of this AD is detected, prior 
to further flight, repair it in accordance with the method approved 
by the Manager, New York Aircraft Certification Office (ACO), FAA, 
Engine and Propeller Directorate.
    (b) Within 10 days after accomplishing the initial and 
repetitive detailed visual inspections required by paragraph (a) of 
this AD, submit a report of any finding(s) of cracking to the 
Manager, New York ACO, telephone (516) 256-7525; fax (516) 568-2716. 
Information collection requirements contained in this regulation 
have been approved by the Office of Management and Budget (OMB) 
under the provisions of the Paperwork Reduction Act of 1980 (44 
U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-
0056.
    (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. 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.

    (d) 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.
    (e) The inspections shall be done in accordance with Canadair 
Regional Jet Alert Service Bulletin A601R-53-045, dated June 25, 
1997. 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 Transport Canada Aviation. 
Copies may be inspected at the FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington; or at the New York 
Aircraft Certification Office (ACO), FAA, Engine and Propeller 
Directorate; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.
    (f) This amendment becomes effective on July 22, 1997. All 
persons except those persons to whom it was made immediately 
effective by emergency AD 97-14-11, issued on June 27, 1997, which 
contained the requirements of this amendment.

    Issued in Renton, Washington, on July 11, 1997.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-18934 Filed 7-16-97; 8:45 am]
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