Airworthiness Directives; Bombardier Model CL-600-2B19 Series Airplanes

[Federal Register Volume 66, Number 210 (Tuesday, October 30, 2001)]
[Rules and Regulations]
[Pages 54658-54661]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-27068]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-68-AD; Amendment 39-12488; AD 2001-22-09]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model CL-600-2B19 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Bombardier Model CL-600-2B19 series airplanes, 
that requires repetitive eddy current inspections for cracking of the 
main landing gear (MLG) main fittings, and replacement with a new or 
serviceable MLG, if necessary. This action also requires servicing the 
MLG shock struts; inspecting the MLG shock struts for nitrogen 
pressure, visible chrome dimension, and oil leakage; and performing 
corrective actions, if necessary. The actions specified by this AD are 
intended to prevent failure of the MLG main fitting, which could result 
in collapse of the MLG upon landing. This action is intended to address 
the identified unsafe condition.

DATES: Effective December 4, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 4, 2001.

ADDRESSES: The service information referenced in this AD may be 
obtained from Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 
6087, Station Centreville, Montreal, 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, 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, 
ANE-171, FAA, 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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Bombardier Model CL-600-
2B19 series airplanes was published as a supplemental notice of 
proposed rulemaking (NPRM) in the Federal Register on March 23, 2001 
(66 FR 16156). That action proposed to require repetitive eddy current 
inspections for cracking of the main landing gear (MLG) main fittings, 
and replacement with a new or serviceable MLG, if necessary. That 
action also proposed to require servicing the MLG shock struts; 
inspecting the MLG shock struts for nitrogen pressure, visible chrome 
dimension, and oil leakage; and performing corrective actions, if 
necessary.

Public Comment

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request To Revise the Applicability

    One commenter points out that the inspection specified in paragraph 
(a) of the NPRM requires compliance with Part ``B'' of Bombardier Alert 
Service Bulletin A601R-32-079, dated December 1, 2000; however, 
Appendix 1 of that alert service bulletin states that the inspection is 
necessary only for MLG main fittings having part numbers (P/Ns) 17064-
101, 17064-102, 17064-103, and 17064-104, not to all airplanes having 
serial numbers 7003 and subsequent. The commenter explains that 
airplanes currently being delivered have MLG main fittings having P/Ns 
17064-105 and 17064-106. The FAA infers that the commenter is 
requesting that we revise the applicability of the final rule.
    The FAA agrees with the commenter. We have verified with Transport 
Canada Civil Aviation (TCCA), which is the airworthiness authority for 
Canada, that airplanes having MLG main fittings having P/Ns 17064-105 
and 17064-106 are not subject to the requirements of this final rule. 
Therefore, we have revised the applicability of the final rule to 
clarify that the final rule applies to Bombardier Model CL-600-2B19 
series airplanes, certificated in any category, having serial number 
7003 and subsequent, and equipped with a MLG main fitting having P/N 
17064-101, 17064-102, 17064-103, or 17064-104.

Requests To Withdraw the NPRM

    1. One commenter requests that the NPRM be withdrawn. The commenter 
states that, since the reason for the NPRM was one event of a 
misserviced strut by a foreign air carrier, it is not necessary to 
issue an AD. In addition,

[[Page 54659]]

the commenter suggests that requiring repetitive strut servicing could 
be done by mandating that the strut inspection be added to the 
operators' inspection programs. The commenter contends that 
incorporating such inspection requirements into the inspection program 
is preferred by operators.
    2. Another commenter states that it has conducted 1,496 eddy 
current inspections in accordance with the alert service bulletin 
referenced in the NPRM and has found no discrepancies. This same 
commenter also states that it has been servicing the shock struts 
beyond the requirements specified in paragraph (b) of the NPRM by 
performing a complete reservicing of the shock strut with oil and 
nitrogen every 12 months. The FAA infers that the commenter is 
requesting that the NPRM be withdrawn.
    3. Another commenter suggests that an annual complete reservicing 
of the MLG shock strut performed in conjunction with an annual eddy 
current inspection is an equivalent or better level of safety than the 
actions proposed in the NPRM. The commenter notes that the brake lines 
are clamped to the MLG main fittings and must be moved or removed to 
gain access to the inspection area. Therefore, the commenter asserts 
that its proposed actions would have the benefit of reducing the 
adverse affects on reliability and safety impact caused by frequent 
disturbance of the brake lines.
    The FAA does not concur that the NPRM should be withdrawn for the 
following reasons:
    1. TCCA, has advised us that three cases of premature failures of 
the MLG have been reported. Because implementation and quality of 
various existing maintenance programs may differ, we have determined 
that by issuing an AD to require eddy current inspections for cracks 
and replacement, if necessary, with a new or serviceable fitting, (and, 
as required by paragraph (b) of this AD, servicing and inspecting the 
MLG shock struts to determine the nitrogen pressure, visible chrome 
dimension and any oil leakage), the identified unsafe condition will be 
addressed appropriately.
    2. In requiring the actions specified in this final rule, the FAA 
has not precluded an operator's prerogative to perform additional 
actions to further increase the safety level that an operator may wish 
to take. As stated previously, we acknowledge that some operators' 
maintenance programs may be of a higher quality than others. However, 
our obligation remains to issue an AD to address the identified unsafe 
condition; and the rule must apply to everyone to ensure that all 
affected airplanes are covered, regardless of who operates them. 
However, under the provisions of paragraph (g) of the final rule, we 
may approve requests for an alternate method of compliance if data are 
submitted to substantiate that such a method would provide an 
acceptable level of safety.
    3. The FAA does not agree that an annual complete reservicing of 
the MLG shock strut performed in conjunction with an annual eddy 
current inspection is equivalent to or a better level of safety than 
the actions required by this final rule. Since the airplane model 
accumulates an average of approximately 2,500 flight cycles per year, 
that would require the eddy current inspection only every 2,500 flight 
cycles. However, according to the investigation that was conducted by 
the original equipment manufacturer (OEM), it took only 2,000 flight 
cycles for the cracking to develop from initiation to critical size. 
Therefore, we have determined that it is necessary to require 
inspections at intervals not to exceed 500 flight cycles.
    As to the adverse affects on the reliability and safety impact 
caused by frequent disturbance of the brake lines, we point out that 
the inspection and its repetitive interval are not only consistent with 
the OEM service bulletin, but also include specific procedures for 
handling the brake lines with minimal disturbance. No change is 
necessary to the final rule regarding these requests.

Requests To Remove Certain Paragraphs of the NPRM

    Two commenters state that the requirements of paragraphs (c) and 
(d) of the NPRM are unnecessary. One commenter states that paragraphs 
(c) and (d) of the NPRM, which require ``inspection of shock strut 
servicing,'' per Bombardier Alert Service Bulletin A601R-32-079, are 
already incorporated into the Maintenance Review Board (MRB) document, 
Task 32-00-00-09 (100 flight hours/routine check) and Task 32-00-00-11 
(400 flight hours/A check). The FAA infers that the commenters are 
requesting that paragraphs (c) and (d) of the NPRM be removed.
    The FAA does not agree. Although the inspection and servicing of 
the shock struts required by paragraphs (c) and (d) of the final rule 
may be the same as the MRB document, our obligation remains to issue an 
AD to address the identified unsafe condition. However, under the 
provisions of paragraph (g) of the final rule, we may approve requests 
for an alternate method of compliance if data are submitted to 
substantiate that such a method would provide an acceptable level of 
safety.
    One of those commenters also notes that paragraph (e) of the NPRM 
``requires extension of repetitive inspection.'' The commenter states 
that, based on the results of 1,496 negative eddy current inspections, 
and the fact that the inspections are incorporated into the MRB 
document, paragraph (e) of the NPRM is not necessary.
    The FAA does not concur that paragraph (e) of the NPRM is 
unnecessary. We point out that in paragraph (e) of this final rule, the 
extension of the inspection interval from every 500 flight cycles to 
every 1,000 flight cycles is not ``required,'' but ``may'' be extended 
if the conditions specified in paragraph (e) of the final rule are met. 
In accordance with the provisions of that paragraph, if an operator 
does not wish to extend the repetitive inspection interval, there is no 
requirement to do so.

Requests To Revise the Requirements of Paragraph (a) of the NPRM

    One commenter requests that paragraph (a) of the NPRM be revised to 
add the visual inspection that is specified in the alert service 
bulletin, which is referenced as the source of service information in 
the NPRM. The commenter notes that the alert service bulletin only 
specifies an eddy current inspection if cracking is detected during the 
visual inspection. This same commenter also requests that paragraph (a) 
of the NPRM be revised to reflect a compliance threshold of 1,000 hours 
with escalation to a ``C'' check (currently 4,000 flight hours for that 
operator's operations).
    The FAA does not agree with either of the commenter's requests. The 
three instances of premature failures of the MLG main fittings 
indicates that the crack propagation is rapid in high-strength steel 
material. In fact, investigation into those three failure cases 
revealed that the crack growth from initiation to critical crack size 
was about 2,000 flight cycles. Since eddy current inspections are more 
reliable in detecting such rapid crack growth, we find that the 
repetitive inspection interval of 500 flight cycles required by 
paragraph (a) of the final rule to be appropriate.

Requests To Extend the Repetitive Inspection Intervals

    Two commenters request that the repetitive inspection interval of 
500 flight cycles specified in paragraph (a) of the NPRM be extended. 
One commenter asks that the repetitive

[[Page 54660]]

inspection interval be revised to require the inspection every ``C'' 
check. This commenter justifies an extension of the repetitive 
inspections based on the fact that it has already accomplished three 
consecutive inspections (500 flight cycles) per the Bombardier alert 
service bulletin specified in the NPRM, and has found no defects. The 
commenter states that the current maintenance program effectively 
prevents improper servicing. The other commenter requests that the 
repetitive inspection interval be extended to every ``C'' check after a 
reasonable number of non-destructive testing (NDT) inspections (perhaps 
two) are done at the 1,000 flight cycle interval. Both commenters state 
that, since they are aware of only one cracking occurrence, there is no 
proof that there is an inherent flaw in the MLG main fitting.
    The FAA does not concur that the repetitive inspection interval may 
be extended. We stated previously that TCCA has advised us that three 
cases of premature failures of the MLG have been reported. In addition, 
we also stated previously that the repetitive inspection interval was 
based on the findings of the investigation into the rapid crack growth 
that occurred on the MLG main fittings. No change to the final rule in 
this regard is necessary. However, under the provisions of paragraph 
(g) of the final rule, we may approve requests for adjustments to the 
compliance time if data are submitted to substantiate that such an 
adjustment would provide an acceptable level of safety.

Interim Action

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

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the change described 
previously. The FAA has determined that this change will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 339 Bombardier Model CL-600-2B19 series 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 236 airplanes of U.S. registry will be affected by this 
proposed AD, that it will take approximately 3 work hours per airplane 
to accomplish an eddy current inspection, and the servicing actions, 
and inspections specified in paragraphs (a), (b), and (c) of this AD. 
We estimate that the average labor rate is $60 per work hour. Based on 
these figures, the cost impact of this AD on U.S. operators is 
estimated to be $42,480, or $180 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the requirements of this AD 
action, and that no operator would accomplish those actions in the 
future if this AD were not adopted. The cost impact figures discussed 
in AD rulemaking actions represent only the time necessary to perform 
the specific actions actually required by the AD. These figures 
typically do not include incidental costs, such as the time required to 
gain access and close up, planning time, or time necessitated by other 
administrative actions.

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.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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:

2001-22-09  Bombardier, Inc. (Formerly Canadair): Amendment 39-
12488. Docket 2000-NM-68-AD.

    Applicability: Model CL-200-2B19 series airplanes, certificated 
in any category, having serial numbers 7003 and subsequent, and 
equipped with a main landing gear (MLG) main fitting having part 
number (P/N) 17064-101, 17064-102, 17064-103, or 17064-104.

    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 (g) 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 failure of MLG main fitting, which could result in 
collapse of the MLG upon landing, accomplish the following:

Inspection and Replacement

    (a) Prior to the accumulation of 1,500 total flight cycles, or 
within 150 flight cycles after the effective date of this AD, 
whichever occurs later: Perform an eddy current inspection to detect 
cracking of the MLG main fittings, in accordance with Part B of the 
Accomplishment Instructions of Bombardier Alert Service Bulletin 
A601R-32-079, Revision D, dated December 1, 2000. If any cracking is 
found, prior to further flight, replace the cracked fitting with a 
new or serviceable fitting in accordance with the alert service 
bulletin. Repeat the inspection thereafter at intervals not to 
exceed 500 flight cycles.

Servicing the Shock Struts

    (b) Prior to the accumulation of 1,500 total flight cycles since 
the date of manufacture, or within 500 flight cycles after the 
effective date of this AD, whichever occurs later: Perform a 
servicing (Oil and Nitrogen) of the MLG shock struts (left and right 
main landing shock struts), in accordance with Part C (for airplanes 
on the ground) or Part D (for airplanes on jacks) of the 
Accomplishment Instructions of Bombardier Alert Service Bulletin 
A601R-32-079, Revision D, dated December 1, 2000.

[[Page 54661]]

Other Inspections

    (c) Within 500 flight cycles after completing the actions 
required by paragraph (b) of this AD: Perform an inspection of the 
MLG left and right shock struts for nitrogen pressure, visible 
chrome dimension, and oil leakage, in accordance with Part E of the 
Accomplishment Instructions of Bombardier Alert Service Bulletin 
A601R-32-079, Revision D, dated December 1, 2000. Thereafter, repeat 
the inspection at intervals not to exceed 500 flight cycles.

Corrective Actions for Certain Inspections

    (d) If the chrome extension dimension of the shock strut 
pressure reading is outside the limits specified in the Airplane 
Maintenance Manual, Task 32-11-05-220-801, or any oil leakage is 
found: Prior to further flight, service the MLG shock strut in 
accordance with Part C (for airplanes on the ground) or Part D (for 
airplanes on jacks) of the Accomplishment Instructions of Bombardier 
Alert Service Bulletin A601R-32-079, Revision D, dated December 1, 
2000.

Extension of the Repetitive Interval

    (e) After the effective date of this AD: After a total of five 
consecutive inspections of the MLG shock struts that verify that the 
shock struts are serviced properly, and a total of five consecutive 
eddy current inspections of the MLG main fitting has been 
accomplished that verify there is no cracking of the main fitting, 
in accordance with Bombardier Alert Service Bulletin A601R-32-079, 
Revision D, dated December 1, 2000, the repetitive interval for the 
eddy current inspections required by paragraph (a) of this AD may be 
extended from every 500 flight cycles to every 1,000 flight cycles.

Reporting Requirement

    (f) Within 30 days after each inspection and servicing required 
by paragraphs (a), (b), and (c) of this AD, report all findings, 
positive or negative, to: Bombardier Aerospace, Regional Aircraft, 
CRJ Action Desk, fax number 514-855-8501. 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.

Alternative Methods of Compliance

    (g) 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 Aircraft Certification 
Office (ACO), FAA. 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.

Special Flight Permits

    (h) 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

    (i) The actions shall be done in accordance with Bombardier 
Alert Service Bulletin A601R-32-079, Revision D, dated December 1, 
2000. 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., Canadair, 
Aerospace Group, P.O. Box 6087, Station Centre-ville, Montreal, 
Quebec H3C 3G9, Canada. Copies may be inspected at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, 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 3: The subject of this AD is addressed in Canadian 
airworthiness directive CF-1999-32R1, dated January 22, 2001.

Effective Date

    (j) This amendment becomes effective on December 4, 2001.

    Issued in Renton, Washington, on October 22, 2001.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-27068 Filed 10-29-01; 8:45 am]
BILLING CODE 4910-13-P

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