DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0795; Project Identifier 2019-CE-054-AD]
RIN 2120-AA64

Airworthiness Directives; Daher Aerospace (Type Certificate
Previously Held by SOCATA) 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 Daher Aerospace (type certificate previously held by SOCATA)
Models TB 20 and TB 21 airplanes. This AD was prompted by mandatory
continuing airworthiness information (MCAI) originated by an aviation
authority of another country to identify and correct an unsafe
condition on an aviation product. The MCAI describes the unsafe
condition as cracks on the main landing gear (MLG) legs. This proposed
AD would require repetitively inspecting the MLG and performing all
applicable corrective actions. 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 November 1,
2021.

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 https://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 Daher
Aircraft Inc., Pompano Beach Airpark, 601 NE 10th Street, Pompano
Beach, FL 33060; phone: (954) 893-1400; website: www.tbm.aero. You may
view this service information at the FAA, Airworthiness Products
Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106.
For information on the availability of this material at the FAA, call
(816) 329-4148.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0795; 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, the MCAI,
any comments received, and other information. The street address for
Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Gregory Johnson, Aviation Safety
Engineer, FAA, General Aviation & Rotorcraft Section, International
Validation Branch, 901 Locust, Room 301, Kansas City, MO 64106; phone:
(720) 626-5462; fax: (816) 329-4090; email: gregory.johnson@faa.gov.

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 the ADDRESSES section. Include "Docket No. FAA-2021-0795;
Project Identifier 2019-CE-054-AD" 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 the 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
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this proposed AD.

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 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
Gregory Johnson, Aviation Safety Engineer, FAA, General Aviation &
Rotorcraft Section, International Validation Branch, 901 Locust, Room
301, Kansas City, MO 64106. Any commentary that the FAA receives which
is not specifically designated as CBI will be placed in the public
docket for this rulemaking.

Background

The European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Union, has issued
EASA AD 2019-0274, dated November 6, 2019 (referred to after this as
"the MCAI"), to address an unsafe condition on all Daher Aerospace
(formerly SOCATA) Models TB 20 and TB 21 airplanes. The MCAI states:

Occurrences have been reported of finding cracks on MLG legs of
TB 20 and TB 21 aeroplanes.

This condition, if not detected and corrected, could lead to
structural failure of an MLG leg and consequent MLG collapse,
possibly resulting in damage to the aeroplane and injury to
occupants.

To address this potential unsafe condition, DAHER Aerospace
issued the [service bulletin] SB to provide inspection instructions.

For the reasons described above, this [EASA] AD requires
repetitive special detailed inspections (SDI) using magnetic
particle method of the affected MLG area, and, depending on
findings, accomplishment of applicable corrective action(s).

You may examine the MCAI in the AD docket at https://www.regulations.
gov by searching for and locating Docket No. FAA-2021-0795.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Daher Service Bulletin SB 10-154-32, dated
September 2019. The service information contains procedures for
repetitively inspecting the MLG area for cracks and performing any
rework and repair. 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 the ADDRESSES section.

FAA's Determination

This product has been approved by the aviation authority of another
country, and is approved for operation in the United States. Pursuant
to the FAA's bilateral agreement with this State of Design Authority,
it has notified the FAA of the unsafe condition described in the MCAI
and service information referenced above. The FAA is issuing this NPRM
after determining the unsafe condition described previously is likely
to exist or develop on other products of the same type design.

Proposed AD Requirements

This proposed AD would require accomplishing the actions specified
in the service information already described.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 52 airplanes of U.S. registry. The FAA also estimates that it
would take about 8 work-hours per airplane to perform the magnetic
particle inspection that would be required by this proposed AD. The
average labor rate is $85 per work-hour.

Based on these figures, the FAA estimates the inspection cost of
this proposed AD on U.S. operators to be $35,360, or $680 per airplane,
per inspection cycle.

In addition, the FAA estimates that any necessary rework would take
12 work-hours and require parts costing $400, for a cost of $1,420 per
airplane. The FAA has no way of determining the number of airplanes
that may need these actions. If the reworked MLG area is found damaged
during a follow-on magnetic particle inspection, because the damage may
vary considerably from airplane to airplane, the FAA has no way of
estimating this repair cost.

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

(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

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