AD 2022-03-08 Requires Inspecting The Elevator Control Pushrod For Water And Corrosion

The FAA is adopting a new airworthiness directive (AD) for all Fiberglas-Technik Rudolf Lindner GmbH & Co. KG (type certificate previously held by GROB Aircraft AG, Grob Aerospace GmbH i.l., Grob Aerospace GmbH, Burkhart Grob  Luft–und Raumfahrt GmbH & Co. KG) Model G102 ASTIR CS, G103 TWIN ASTIR, G103 TWIN II, G103A TWIN II ACRO, G103C TWIN III ACRO, and G 103 C TWIN III SL gliders.

This AD was prompted by mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as corrosion on the elevator control pushrod. This AD requires inspecting the elevator control pushrod for water and corrosion and replacing the pushrod if necessary. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective March 17, 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 Fiberglas-Technik Rudolf Lindner GmbH & Co. KG Model G102 ASTIR CS, G103 TWIN ASTIR, G103 TWIN II, G103A TWIN II ACRO, G103C TWIN III ACRO, and G 103 C TWIN III SL gliders. The NPRM published in the Federal Register on October 29, 2021 (86 FR 59903). 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 EASA AD 2020-0138, dated June 19, 2020 (referred to after this as “the MCAI”), to address an unsafe condition on Fiberglas-Technik Rudolf Lindner GmbH & Co. KG Model G102 ASTIR CS, G103 TWIN ASTIR, G103 TWIN II, G103A TWIN II ACRO, G103C TWIN III ACRO, and G 103 C TWIN III SL gliders.

The MCAI states:

• During a routine inspection, a severely corroded elevator control pushrod was found in the vertical fin on a Grob TWIN ASTIR sailplane. The technical investigation results revealed that water had soaked into the elevator control pushrod, causing the corrosion damage and subsequent considerable weakening of the steel tube pushrod.
• This condition, if not detected and corrected, could lead to failure of the elevator control pushrod, possibly resulting in loss of control of the sailplane.
• To address this unsafe condition, Fiberglas-Technik R. Lindner GmbH & Co.KG published the [technische mitteilung/service bulletin] TM/SB and [anweisung/instructions] A/I-G09, at original issue, providing instructions for elevator control pushrod inspection and replacement. Prompted by this development, EASA issued AD 2020-0121 to require a one-time inspection of the elevator control pushrod in the vertical fin and, depending on findings, replacement.
• After EASA AD 2020-0121 was issued, it was determined that Grob G 103 “TWIN II” sailplanes, and additional Grob G 103 A “TWIN II ACRO” sailplanes, are also prone to elevator control pushrod corrosion and Fiberglas-Technik R.Lindner GmbH & Co.KG issued the TM/SB to make the inspection instructions applicable to these sailplane models.
• For the reasons described above, this [EASA] AD retains the requirements of EASA AD 2020-0121, which is superseded, and expands the Applicability.

You may examine the MCAI in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0944.

FMI: www.regulations.gov