[Federal Register Volume 88, Number 22 (Thursday, February 2, 2023)]
[Rules and Regulations]
[Pages 6972-6974]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-02006]



[[Page 6972]]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0991; Project Identifier AD-2022-00155-T; 
Amendment 39-22299; AD 2023-01-05]
RIN 2120-AA64


Airworthiness Directives; Learjet, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Learjet, Inc., Model 45 airplanes. This AD was prompted by a 
determination that new or more restrictive airworthiness limitations 
are necessary. This AD requires revising the existing inspection 
program to incorporate reduced inspection intervals for the anti-ice 
manifold assembly. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective March 9, 2023.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of March 9, 
2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2022-0991; or in person at Docket Operations between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD 
docket contains this final rule, any comments received, and other 
information. The address for Docket Operations is U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
    Material Incorporated by Reference:
     For service information identified in this final rule, 
contact Learjet, Inc., One Learjet Way, Wichita, KS 67209-2942; 
telephone 316-946-2000; fax 316-946-2220; email 
bombardier.com">[email protected]bombardier.com; website bombardier.com.
     You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 2200 South 
216th St., Des Moines, WA. For information on the availability of this 
material at the FAA, call 206-231-3195. It is also available at 
regulations.gov under Docket No. FAA-2022-0991.

FOR FURTHER INFORMATION CONTACT: Adam Hein, Aerospace Engineer, 
Mechanical Systems and Propulsion Section, FAA, Wichita ACO Branch, 
1801 S Airport Road, Wichita, KS 67209; telephone (316) 946-4116; 
email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain Learjet, Inc., 
Model 45 airplanes. The NPRM published in the Federal Register on 
August 11, 2022 (87 FR 49556). The NPRM was prompted by a determination 
that new or more restrictive airworthiness limitations are necessary. 
In the NPRM, the FAA proposed to require revising the existing 
inspection program to incorporate reduced inspection intervals for the 
anti-ice manifold assembly.
    The FAA issued a supplemental notice of proposed rulemaking (SNPRM) 
to amend 14 CFR part 39 by adding an AD that would apply to certain 
Learjet, Inc., Model 45 airplanes. The SNPRM published in the Federal 
Register on November 10, 2022 (87 FR 67834). The SNPRM was prompted by 
a determination that additional airplanes needed to be added to the 
applicability. The SNPRM proposed to require revising the existing 
inspection program to incorporate reduced inspection intervals for the 
anti-ice manifold assembly and to add airplanes to the applicability. 
The FAA is issuing this AD to address metal fragments breaking off the 
anti-ice manifold assembly due to fatigue, which could block a duct in 
the anti-ice system and result in an unannunciated loss of ice 
protection and subsequent loss of control of the airplane.

Related Rulemaking

    The FAA issued AD 2001-03-05, Amendment 39-12109 (66 FR 10353, 
February 15, 2001) (AD 2001-03-05), for certain Learjet Model 45 
airplanes. AD 2001-03-05 requires, among other actions, revising the 
existing Learjet 45 maintenance program to incorporate additional 
inspections and maintenance practices for the anti-ice manifold 
assembly, including a 600-hour repetitive inspection interval of an 
earlier design/part number of the anti-ice manifold. Since the FAA 
issued AD 2001-03-05, the anti-ice manifold was redesigned, and the 
inspection interval was extended to 1,200 flight hours. The design 
approval holder subsequently determined that the design improvements 
made to the anti-ice manifold assembly did not fully address the 
original issue of vane cracking, so the 1,200-hour inspection on the 
redesigned part is insufficient. However, the FAA determined that a 
repetitive inspection interval of 600 flight hours is sufficient to 
address the unsafe condition. Therefore, this AD requires revising the 
existing inspection program to incorporate a reduced 600-hour 
inspection interval for the redesigned part. Accomplishing the required 
actions in this AD terminates the requirements of paragraph (c) of AD 
2001-03-05.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from two individuals who supported the 
SNPRM without change.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes, this 
AD is adopted as proposed in the SNPRM. None of the changes will 
increase the economic burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Learjet 40 Maintenance Manual Temporary Revision 
(TR) 04-33 and Learjet 45 Maintenance Manual TR 04-48, both dated 
January 18, 2022. This service information specifies reduced inspection 
intervals for the anti-ice manifold assembly. These documents are 
distinct since they apply to different airplane configurations. This 
service information is reasonably available because the interested 
parties have access to it through their normal course of business or by 
the means identified in ADDRESSES.

Costs of Compliance

    The FAA estimates that this AD affects 481 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

[[Page 6973]]



                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Inspection program revision...........  1 work-hour x $85 per                 $0             $85         $40,885
                                         hour = $85.
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: General requirements. 
Under that section, Congress charges the FAA with promoting safe flight 
of civil aircraft in air commerce by prescribing regulations for 
practices, methods, and procedures the Administrator finds necessary 
for safety in air commerce. This regulation is within the scope of that 
authority because it addresses an unsafe condition that is likely to 
exist or develop on products identified in this rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD 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.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, 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.

List of Subjects in 14 CFR Part 39

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

The Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2023-01-05 Learjet, Inc.: Amendment 39-22299; Docket No. FAA-2022-
0991; Project Identifier AD-2022-00155-T.

(a) Effective Date

    This airworthiness directive (AD) is effective March 9, 2023.

(b) Affected ADs

    This AD affects AD 2001-03-05, Amendment 39-12109 (66 FR 10353, 
February 15, 2001) (AD 2001-03-05).

(c) Applicability

    This AD applies to Learjet, Inc., Model 45 (Learjet 40), Model 
45 (Learjet 45), Model 45 (Learjet 70), and Model 45 (Learjet 75) 
airplanes, certificated in any category, with an original 
airworthiness certificate or original export certificate of 
airworthiness issued on or before January 18, 2022.

(d) Subject

    Air Transport Association (ATA) of America Code 36, Pneumatic.

(e) Unsafe Condition

    This AD was prompted by a determination that new or more 
restrictive airworthiness limitations are necessary. The FAA is 
issuing this AD to address metal fragments breaking off the anti-ice 
manifold assembly due to fatigue, which could block a duct in the 
anti-ice system and result in an unannunciated loss of ice 
protection and subsequent loss of control of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Maintenance or Inspection Program Revision

    (1) For Learjet 40 and 45 variants: Within 60 days after the 
effective date of this AD, revise the existing inspection program by 
incorporating the information in Learjet 40 Maintenance Manual 
Temporary Revision (TR) 04-33 or Learjet 45 Maintenance Manual TR 
04-48, both dated January 18, 2022, as applicable. The initial 
compliance time for the inspection is at the applicable time 
specified in paragraph (g)(1)(i) or (ii) of this AD.
    (i) For airplanes with more than 600 flight hours since the most 
recent inspection of the anti-ice manifold assembly was performed as 
of the effective date of this AD: Do the inspection within 100 
flight hours or 60 days after the effective date of this AD, 
whichever occurs first.
    (ii) For airplanes with 600 flight hours or less since the most 
recent inspection of the anti-ice manifold assembly was performed as 
of the effective date of this AD: Do the inspection within 600 
flight hours after the most recent inspection or within 100 flight 
hours after the effective date of this AD, whichever occurs later.
    (2) For Learjet 70 and 75 variants: Within 60 days after the 
effective date of this AD, revise the existing inspection program to 
incorporate the information identified in figure 1 to paragraph 
(g)(2) of this AD. The initial compliance time for the inspection is 
at the applicable time specified in paragraph (g)(2)(i) or (ii) of 
this AD.

Figure 1 to paragraph (g)(2)--Anti-Ice Inspection Tasks
[GRAPHIC] [TIFF OMITTED] TR02FE23.000


[[Page 6974]]


    (i) For airplanes with more than 600 flight hours since the most 
recent inspection of the anti-ice manifold assembly was performed as 
of the effective date of this AD: Do the inspection within 100 
flight hours or 60 days after the effective date of this AD, 
whichever occurs first.
    (ii) For airplanes with 600 flight hours or less since the most 
recent inspection of the anti-ice manifold assembly was performed as 
of the effective date of this AD: Do the inspection within 600 
flight hours after the most recent inspection or within 100 flight 
hours after the effective date of this AD, whichever occurs later.

(h) No Alternative Actions or Intervals

    After the existing inspection program has been revised as 
required by paragraph (g) of this AD, no alternative actions (e.g., 
inspections) or intervals, may be used unless the actions and 
intervals are approved as an alternative method of compliance (AMOC) 
in accordance with the procedures specified in paragraph (k) of this 
AD.

(i) Terminating Action for Paragraph (c) of AD 2001-03-05

    Accomplishing the revision of the existing inspection program 
required by paragraph (g) of this AD terminates the requirements of 
paragraph (c) of AD 2001-03-05.

(j) Special Flight Permit

    Special flight permits may be issued in accordance with 14 CFR 
21.197 and 21.199 to operate the airplane to a location where the 
airplane can be inspected, provided the airplane is restricted from 
flying into known icing conditions.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Wichita ACO Branch, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request 
to your principal inspector or responsible Flight Standards Office, 
as appropriate. If sending information directly to the manager of 
the certification office, send it to the attention of the person 
identified in paragraph (l) of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the responsible Flight Standards Office.

(l) Related Information

    For more information about this AD, contact Adam Hein, Aerospace 
Engineer, Mechanical Systems and Propulsion Section, FAA, Wichita 
ACO Branch, 1801 S Airport Road, Wichita, KS 67209; telephone (316) 
946-4116; email: [email protected].

(m) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Learjet 40 Maintenance Manual Temporary Revision 04-33, 
dated January 18, 2022.
    (ii) Learjet 45 Maintenance Manual Temporary Revision 04-48, 
dated January 18, 2022.
    (3) For service information identified in this AD, contact 
Learjet, Inc., One Learjet Way, Wichita, KS 67209-2942; telephone 
316-946-2000; fax 316-946-2220; email bombardier.com">[email protected]bombardier.com; 
website bombardier.com.
    (4) You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 2200 
South 216th St., Des Moines, WA. For information on the availability 
of this material at the FAA, call 206-231-3195.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, [email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on January 6, 2023.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-02006 Filed 2-1-23; 8:45 am]
BILLING CODE 4910-13-P


