[Federal Register Volume 64, Number 216 (Tuesday, November 9, 1999)]
[Proposed Rules]
[Pages 61039-61042]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-29177]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-192-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Bombardier Model 
CL-600-2B19 (Regional Jet Series 100 and 200) series airplanes, that 
currently requires repetitive inspections to detect cracks of a certain 
bulkhead web of the fuselage at certain locations, and repair, if 
necessary. This action would revise the repetitive inspection intervals 
for certain airplanes, and would require modification or repair, as 
applicable. This proposal is prompted by the development of a 
modification that will adequately address the identified unsafe 
condition. The actions specified by the proposed AD are intended to 
detect and correct fatigue cracking, which could result in uncontrolled 
depressurization of the airplane and/or reduced structural integrity of 
the fuselage.

DATES: Comments must be received by December 9, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-192-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., Canadair, Aerospace Group, P.O. Box 
6087, Station Centre-ville, 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, Engine and 
Propeller Directorate, New York Aircraft Certification Office, 10 Fifth 
Street, Third Floor, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT: George Duckett, 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) 256-7525; 
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 98-NM-192-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. 98-NM-192-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On July 11, 1997, the FAA issued AD 97-14-11, amendment 39-10082 
(62 FR 38206, July 17, 1997), applicable to certain Bombardier Model 
CL-600-2B19 (Regional Jet Series 100 and 200) series airplanes, to 
require repetitive inspections to detect cracks of a certain bulkhead 
web of the fuselage at certain locations, and repair, if necessary. 
That action was 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 requirements of that 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.

Actions Since Issuance of Previous Rule

    In the preamble of AD 97-14-11, the FAA indicated that the actions 
required by that AD were considered ``interim action'' and that further 
rulemaking action was being considered to require modification of the 
affected fuselage frames once new service information was available. 
The manufacturer has now released such information, and the FAA has 
determined that further rulemaking is indeed necessary; this proposed 
AD follows from that determination.

Issuance of New Service Information

    The manufacturer has issued Canadair Regional Jet Alert Service 
Bulletin A601R-53-045, Revision `D,' including Appendix 1, dated 
December 22, 1997, which describes procedures for repetitive detailed 
inspections to detect cracks of a certain bulkhead web of the fuselage 
at certain locations; and follow-on corrective actions, if necessary. 
The

[[Page 61040]]

inspections also involve determining whether a crack located at the 
pressure bulkhead of frame station (FS)409+128 is within certain limits 
specified in the alert service bulletin.
    In the event that a crack is determined to be outside the limits 
specified in Part A of the Accomplishment Instructions of the alert 
service bulletin, the follow-on corrective actions would include a high 
frequency eddy current (HFEC) inspection of the forward side of the 
web, to detect cracks of fuselage FS409+128 bulkhead web along the 
upper edge of the horizontal angle. As listed in Part A of paragraph 
2.B. of the Accomplishment Instructions, airplanes may be returned to 
service provided that any cracking detected is within certain limits 
specified in the alert service bulletin.
    The manufacturer also has issued Canadair Regional Jet Service 
Bulletin 601R-53-046, Revision `B,' dated December 22, 1997, which 
describes procedures for repair of the pressure bulkhead at FS409+128.
    The manufacturer also has issued Canadair Regional Jet Service 
Bulletin 601R-53-047, Revision `D,' including Appendix 1 and Appendix 
2, dated December 22, 1997, describes procedures for modification of 
the affected areas of the pressure bulkhead at FS409+128. This 
modification is only applicable to those airplanes that have been 
inspected and are found to be free of cracks. The modification involves 
the installation of reinforcement components for the pressure bulkhead 
at FS409+128.
    Accomplishment of the actions specified in the service bulletins is 
intended to adequately address the identified unsafe condition. 
Transport Canada Civil Aviation (TCCA) classified Canadair Regional Jet 
Service Bulletins A601R-53-045 and 601R-53-046 as mandatory, but did 
not classify Service Bulletin 601R-53-047 as mandatory, and issued 
Canadian airworthiness directive CF-97-11R2, dated December 22, 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 
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 supersede AD 97-14-11 to 
continue to require repetitive inspections to detect cracks of a 
certain bulkhead web of the fuselage at certain locations. This 
proposed AD would revise the repetitive inspection intervals for 
certain airplanes, and would require modification or repair, as 
applicable. Accomplishment of the modification or repair would 
terminate the requirements of this proposed AD. Certain actions would 
be required to be accomplished in accordance with the service bulletins 
described previously.
    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 Civil 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.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that the Canadair Regional Jet Alert Service 
Bulletin A601R-53-045, Revision `D,' including Appendix 1, dated 
December 22, 1997, recommends that the initial inspection be performed 
no later than 10 flight hours after the alert service bulletin date of 
issuance. This proposed AD would increase the initial inspection 
threshold to require the initial inspection be performed within 20 
flight hours after the effective date of this AD. In developing an 
appropriate initial inspection compliance time for this AD, the FAA 
considered not only the manufacturer's recommendation, but also the 
degree of urgency associated with addressing the subject unsafe 
condition. In light of these factors, the FAA finds a compliance time 
of 20 flight hours for initiating the required actions to be warranted, 
in that it represents an appropriate interval of time allowable for 
affected airplanes to continue to operate without compromising safety.
    Operators also should note that, although the Canadair Regional Jet 
Service Bulletins A601R-53-045, Revision `D,' and 601R-53-046, Revision 
`B,' specify that the manufacturer may be contacted for disposition of 
certain cracking conditions, this proposal would require the repair of 
those conditions to be accomplished in accordance with a method 
approved by the FAA.

Differences Between Proposed Rule and Foreign Airworthiness 
Directive

    The proposed AD would differ from the parallel Canadian 
airworthiness directive in that it would require accomplishment of the 
modification described in Canadair Regional Jet Service Bulletin 601R-
53-047, Revision `D,' within 9 months after the effective date of this 
AD. The parallel Canadian airworthiness directive recommends, but does 
not require, the accomplishment of the modification. Additionally, in 
the event that cracking within certain limits is found, this proposed 
AD would require a repair to be accomplished within 6 months after the 
effective date of this AD, or within 3 months after the initial date 
the crack was detected, whichever occurs later. The Canadian 
airworthiness directive specifies that the airplane may be returned to 
service provided that re-inspections are accomplished at certain flight 
hour intervals. The FAA has determined that, in this case long-term 
continued operational safety will be adequately assured by 
accomplishing the modification or repair to remove the source of the 
problem, rather than by accomplishing repetitive inspections at certain 
flight hour intervals.

Explanation of Applicability

    The applicability of this proposed AD would affect Bombardier Model 
CL-600-2B19 (Regional Jet Series 100) series airplanes, whereas the 
previously issued AD 97-14-11 addressed Bombardier Model CL-600-2B19 
(Regional Jet Series 100 and 200) series airplanes. The FAA 
inadvertently referenced Bombardier Model CL-600-2B19 (Regional Jet 
Series 200) series

[[Page 61041]]

airplanes in the previously issued AD. This airplane series is not type 
certificated in the U.S.
    Additionally, the applicability of this proposed AD excludes any 
airplane on which Canadair Regional Jet Service Bulletins 601R-53-046, 
Revision `B,' dated December 22, 1997, and 601R-53-047, Revision `D,' 
including Appendix 1 and Appendix 2, dated December 22, 1997, has been 
accomplished.

Cost Impact

    There are approximately 77 airplanes of U.S. registry that would be 
affected by this proposed AD.
    The inspection that is currently required by AD 97-14-11 takes 
approximately 2 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the currently required inspection on U.S. operators is 
estimated to be $9,960, or $120 per airplane, per inspection cycle.
    The repair that is proposed in this AD action would take 
approximately 300 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would cost 
approximately $1,828. Based on these figures, the cost impact of the 
repair on U.S. operators is estimated to be $19,828 per airplane.
    The modification that is proposed in this AD action would take 
approximately 212 hours per airplane to accomplish, at an average labor 
rate of $60 per work hour. Required parts would cost approximately 
$935. Based on these figures, the cost impact of the modification on 
U.S. operators is estimated to be $13,655 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the current or proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted. However, the 
FAA has been advised that the manufacturer has committed previously to 
its customers that it will bear the labor costs associated with the 
repair and modification associated with accomplishing the actions 
required by this AD. Additionally, the manufacturer has indicated the 
warranty remedies may be available to defer the cost of the replacement 
parts also associated with accomplishing the actions required by this 
proposed AD.

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 removing amendment 39-10082 (62 FR 
38206, July 17, 1997), and by adding a new airworthiness directive 
(AD), to read as follows:

Bombardier, Inc. (Formerly Canadair): Docket 98-NM-192-AD. 
Supersedes AD 97-14-11, Amendment 39-10082.

    Applicability: Model CL-600-2B19 (Regional Jet Series 100) 
series airplanes, serial numbers 7003 through 7185 inclusive; except 
those airplanes on which Canadair Regional Jet Service Bulletin 
601R-53-046, Revision `B,' dated December 22, 1997, or 601R-53-047, 
Revision `D,' including Appendix 1 and Appendix 2, dated December 
22, 1997, has been accomplished; 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 request approval for an 
alternative method of compliance in accordance with paragraph (d)(1) 
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:

Detailed Visual Inspections

    (a) Perform a detailed visual inspection to detect cracks at 
FS409+128 of the bulkhead web drawing number 601R32208-123 of the 
fuselage, in accordance with Canadair Regional Jet Alert Service 
Bulletin A601R-53-045, Revision `D,' including Appendix 1 and 
Appendix 2, dated December 22, 1997, at the time specified in 
paragraph (a)(1) or (a)(2) of this AD, as applicable, until 
accomplishment of paragraph (b) or (c) of this AD, as applicable.
    (1) For airplanes that have accomplished a detailed visual 
inspection in accordance with AD 97-14-11 prior to the effective 
date of this AD: Perform a subsequent detailed visual inspection 
prior to the accumulation of 1,000 total flight hours, or within 100 
flight hours after the immediately preceding inspection accomplished 
in accordance with AD 97-14-11, whichever occurs later. Thereafter, 
repeat the inspection at intervals not to exceed 100 flight hours.
    (2) For airplanes that have not accomplished a detailed visual 
inspection in accordance with AD 97-14-11 prior to the effective 
date of this AD: Perform a detailed visual inspection within 20 
flight hours after the effective date of this AD. Perform a 
subsequent detailed visual inspection prior to the accumulation of 
1,000 total flight hours, or within 100 flight hours after 
accomplishment of the immediately preceding inspection, whichever 
occurs later. Thereafter, repeat the inspection at intervals not to 
exceed 100 flight hours.
    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.''

    Note 3: Accomplishment of the inspection required by paragraph 
(a) of this AD, prior to the effective date of this AD in accordance 
with Canadair Regional Jet Alert Service Bulletin A601R-53-045, 
dated June 25, 1997; Revision `A,' including Appendix 1, dated June 
26, 1997; Revision `B,' including Appendix 1, dated June 27, 1997; 
or Revision

[[Page 61042]]

`C,' including Appendix 1, dated July 2, 1997; is considered 
acceptable for compliance with the applicable action specified by 
this AD.

Modification

    (b) For any airplane on which no cracking has been detected 
during any inspection required by paragraph (a) of this AD: Within 9 
months after the effective date of this AD, modify FS409+128 of the 
bulkhead web drawing number 601R32208-123 of the fuselage in 
accordance with Canadair Regional Jet Service Bulletin 601R-53-047, 
including Appendix 1, Revision `D,' dated December 22, 1997. 
Accomplishment of this modification terminates the requirements of 
this AD.

    Note 4: Any modification accomplished prior to the effective 
date of this AD in accordance with Canadair Regional Jet Service 
Bulletin 601R-53-047, including Appendix 1 and Appendix 2, dated 
July 18, 1997; Revision `A,' including Appendix 1, dated July 31, 
1997; Revision `B,' including Appendix 1, dated August 22, 1997; or 
Revision `C,' including Appendix 1, dated October 7, 1997; is 
considered acceptable for compliance with the applicable actions 
required by this AD.

Repair

    (c) For any airplane on which any cracking is detected during 
any inspection required by paragraph (a) of this AD: Prior to 
further flight, determine the extent of the cracking as specified in 
Part A of paragraph 2.B. of the Accomplishment Instructions of 
Canadair Regional Jet Alert Service Bulletin A601R-53-045, Revision 
`D,' including Appendix 1, dated December 22, 1997, and accomplish 
the requirements of paragraph (c)(1) or (c)(2), as applicable.
    (1) If the cracking is within the limits specified by Part A of 
paragraph 2.B. of the Accomplishment Instructions of the alert 
service bulletin, accomplish the requirements of paragraphs 
(c)(1)(i) and (c)(1)(ii) of this AD at the time specified in those 
paragraphs.
    (i) Repeat the detailed visual inspection required by paragraph 
(a) of this AD thereafter at intervals not to exceed 100 flight 
hours; and
    (ii) Within 6 months after the effective date of this AD, or 
within 3 months after the initial date the crack was detected, 
whichever occurs later: Repair the affected area in accordance with 
Canadair Regional Jet Service Bulletin 601R-53-046, Revision `B,' 
dated December 22, 1997. Accomplishment of this repair terminates 
the requirements of this AD.

    Note 5: Any repair accomplished prior to the effective date of 
this AD in accordance with Canadair Regional Jet Service Bulletin 
601R-53-046, dated June 27, 1997, or Revision `A,' dated July 2, 
1997, is considered acceptable for compliance with the applicable 
actions specified by this AD.

    (2) If the cracking is outside the limits specified by Part A of 
the Accomplishment Instructions of the alert service bulletin, prior 
to further flight, perform a high frequency eddy current (HFEC) 
inspection to detect cracks of the forward side of the web of 
fuselage FS409+128 bulkhead web drawing number 601R32208-123, along 
the upper edge of the horizontal angle part number 601R32208-73, in 
accordance with Part B of paragraph 2.B. of the Accomplishment 
Instructions of the alert service bulletin.
    (i) If, during any HFEC inspection required by paragraph (c)(2) 
of this AD, any cracking is detected that is within the limits 
specified by Part B of paragraph 2.B. of the Accomplishment 
Instructions of the alert service bulletin, accomplish the 
requirements of paragraphs (c)(2)(i)(A) and (c)(2)(i)(B) of this AD 
at the times specified in those paragraphs.
    (A) Repeat the HFEC inspection required by paragraph (c)(2) of 
this AD thereafter at intervals not to exceed 50 flight hours, and 
repeat the detailed visual inspection required by paragraph (a) of 
this AD thereafter at interval not to exceed 100 flight hours; and
    (B) Within 6 months after the effective date of this AD, or 
within 3 months after the initial date the crack was detected, 
whichever occurs later: Repair the affected area in accordance with 
Canadair Regional Jet Service Bulletin 601R-53-046, Revision `B,' 
dated December 22, 1997. Accomplishment of this repair terminates 
the requirements of this AD.
    (ii) If, during any HFEC inspection required by paragraph (c)(2) 
of this AD, any cracking is detected that is outside the limits 
specified by Part B of paragraph 2.B. of the Accomplishment 
Instructions of the alert service bulletin, prior to further flight, 
determine the extent of the cracking as specified in paragraph 1.D. 
(``Compliance'') of Canadair Regional Jet Service Bulletin 601R-53-
046, Revision `B,' dated December 22, 1997, and accomplish the 
requirements of paragraph (c)(2)(ii)(A) or (c)(2)(ii)(B) of this AD, 
as applicable.
    (A) If the cracking is within the limits specified by paragraph 
1.D. (``Compliance'') of the service bulletin, prior to further 
flight, repair in accordance with the service bulletin. 
Accomplishment of this repair terminates the requirements of this 
AD.
    (B) If the cracking is outside the limits specified by paragraph 
1.D. (``Compliance'') of the service bulletin, prior to further 
flight, repair in accordance with a method approved by the Manager, 
New York Aircraft Certification Office (ACO).

Alternative Methods of Compliance

    (d)(1) 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.
    (d)(2) Alternative methods of compliance, approved previously in 
accordance with AD 97-14-11, amendment 39-10082, are approved as 
alternative methods of compliance for this AD.

    Note 6: 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 7: The subject of this AD is addressed in Canadian 
airworthiness directive CF-97-11R2, dated December 22, 1997.

    Issued in Renton, Washington, on November 2, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-29177 Filed 11-8-99; 8:45 am]
BILLING CODE 4910-13-U