AD 2021-24-16 Describes The Unsafe Condition As Cracks On The Main Landing Gear (MLG) Legs

The FAA is adopting a new airworthiness directive (AD) for all Daher Aerospace (type certificate previously held by SOCATA) Model 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 AD requires repetitively inspecting the MLG and performing all applicable corrective actions. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective January 18, 2022.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all Daher Aerospace (type certificate previously held by SOCATA) Model TB 20 and TB 21 airplanes. The NPRM published in the Federal Register on September 17, 2021 (86 FR 51840). The NPRM was prompted by MCAI originated by the European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union. EASA issued 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) Model 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.

FMI: www.regulations.gov