[Federal Register Volume 87, Number 154 (Thursday, August 11, 2022)]
[Proposed Rules]
[Pages 49556-49559]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-16680]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0991; Project Identifier AD-2022-00155-T]
RIN 2120-AA64


Airworthiness Directives; Learjet, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

DATES: The FAA must receive comments on this proposed AD by September 
26, 2022.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to www.regulations.gov. 
Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, contact Learjet, 
Inc., One Learjet Way, Wichita, KS 67209-2942; telephone 316-946-2000; 
fax 316-946-2220; email [email protected]; internet 
www.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.

Examining the AD Docket

    You may examine the AD docket at www.regulations.gov by searching 
for and locating 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 NPRM, any comments 
received, and other information. The street address for Docket 
Operations is listed above.

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: 

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2022-0991; Project Identifier 
AD-2022-00155-T'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. The FAA 
will consider all comments received by the closing date and may amend 
this proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
www.regulations.gov, including any personal information you provide. 
The agency will also post a report summarizing each substantive verbal 
contact received about this NPRM.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as

[[Page 49557]]

private, and that is relevant or responsive to this NPRM, it is 
important that you clearly designate the submitted comments as CBI. 
Please mark each page of your submission containing CBI as ``PROPIN.'' 
The FAA will treat such marked submissions as confidential under the 
FOIA, and they will not be placed in the public docket of this NPRM. 
Submissions containing CBI should be sent to 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]. Any commentary that the FAA receives 
that is not specifically designated as CBI will be placed in the public 
docket for this rulemaking.

Background

    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. AD 2001-03-05 resulted from anti-ice system difficulties on a 
Learjet Model 45 airplane, generating a warning to the flightcrew of an 
overheat condition of the horizontal stabilizer. The FAA issued AD 
2001-03-05 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.
    AD 2001-03-05 mandates a 600-hour repetitive inspection interval of 
an earlier design/part number of the anti-ice manifold as specified in 
the Learjet 45 maintenance program revision. The part was subsequently 
redesigned outside the scope of AD 2001-03-05, and the inspection 
interval for airplanes with the redesigned part was extended to 1,200 
flight hours by Learjet.
    Since the FAA issued AD 2001-03-05, the design approval holder 
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 proposed AD would require revising the existing 
inspection program to incorporate a reduced 600-hour inspection 
interval for the redesigned part. Accomplishing the proposed actions 
would terminate the requirements of paragraph (c) of AD 2001-03-05.
    The FAA is proposing 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.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

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.
    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.

Proposed AD Requirements in This NPRM

    This proposed AD would require revising the existing inspection 
program to incorporate reduced inspection intervals for the anti-ice 
manifold assembly.
    This proposed AD would require revisions to certain operator 
maintenance documents to include new actions (e.g., inspections). 
Compliance with these actions is required by 14 CFR 91.403(c). For 
airplanes that have been previously modified, altered, or repaired in 
the areas addressed by this proposed AD, the operator may not be able 
to accomplish the actions described in the revisions. In this 
situation, to comply with 14 CFR 91.403(c), the operator must request 
approval for an alternative method of compliance according to paragraph 
(k) of this proposed AD.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 443 airplanes of U.S. registry. The FAA estimates the following 
costs to comply with this proposed AD:

                                                 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         $37,655
                                         hour = $85.
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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

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, and

[[Page 49558]]

    (3) Would 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 Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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:

Learjet, Inc.: Docket No. FAA-2022-0991; Project Identifier AD-2022-
00155-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by September 26, 2022.

(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 all Learjet, Inc., Model 45 (Learjet 40), 
Model 45 (Learjet 45), Model 45 (Learjet 70), and Model 45 (Learjet 
75) airplanes, serial numbers 45-002 through 45-556 inclusive, and 
45-2001 through 45-2146 inclusive, certificated in any category.

(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.
[GRAPHIC] [TIFF OMITTED] TP11AU22.012

    (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)(1) 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

    (1) For more information about this AD, contact Adam Hein, 
Aerospace Engineer,

[[Page 49559]]

Mechanical Systems and Propulsion Section, FAA, Wichita ACO Branch, 
1801 S Airport Road, Wichita, KS 67209; telephone (316) 946-4116; 
email: [email protected].
    (2) 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 [email protected]; 
internet www.bombardier.com. You may view this referenced 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.

    Issued on July 29, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2022-16680 Filed 8-10-22; 8:45 am]
BILLING CODE 4910-13-P