2024-22251. Airworthiness Directives; THOMMEN AIRCRAFT EQUIPMENT AG Digital Air Data Computers

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Replace affected AC32 Digital ADC	12 work-hours × $85 per hour = $1,020	$4,477	$5,497	$2,204,297

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected operators.

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 ( print page 79482)

(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.

§ 39.13

[Amended]

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

Thommen Aircraft Equipment AG: Docket No. FAA-2024-2322; Project Identifier MCAI-2024-00065-Q.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by November 14, 2024.

(b) Affected ADs

None.

(c) Applicability

(1) This AD applies to THOMMEN AIRCRAFT EQUIPMENT AG (THOMMEN) AC32 Digital Air Data Computers (ADCs) having an affected part as defined in paragraph (f)(1) of this AD.

(2) This appliance is installed on, but not limited to, the following aircraft models specified in Table 1 to paragraph (c)(2) of this AD, certificated in any category.

Table 1 to paragraph (c)(2)—Applicable Aircraft Models

Type certificate holder	Aircraft model
Airbus Defense and Space S.A. (type certificate previously held by Construcciones Aeronauticas, S.A.)	CN-235, CN-235-100, CN-235-200, and CN-235-300.
Airbus Helicopters	AS332C, AS332C1, AS332L, AS332L1, AS3323L2.
Airbus Helicopters Deutschland GmbH (AHD)	EC635T2+.
Bell Textron Inc	212, 412, and 412EP.
Bombardier Inc	CL-600-1A11 (600).
Columbia Helicopters Inc	234.
General Atomics Aerotek Systems GmbHl (type certificate formerly held by DORNIER LUFTFAHRT Inc.)	228-100, 228-101, 228-200, 228-201, 228-202, and 228-212.
Gulfstream Aerospace LP	Westwind Astra 1124 (serial numbers 004-0410).
International Air Response	C-130A.
Leonardo S.p.a	A109, A10A, A109A II, A109C, A109K2, A109S, 1099SP, and AW139.
Textron Aviation Inc	200, 300, 500, 501, 550, and 551.
Viking Air Limited	CL-215-6B11 (CL-215T Variant).