AD 2021-26-25

This AD is effective February 24, 2022.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of February 24, 2022.

For service information identified in this final rule, contact Schempp-Hirth Flugzeugbau GmbH, Krebenstrasse 25, 73230 Kirchheim/Teck, Germany; phone: +49 7021 7298-0; fax: +49 7021 7298-199; email: info@schempp-hirth.com; website: https://www.schempp-hirth.com. 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 (817) 222-5110. It is also available at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0878.

Jim Rutherford, Aviation Safety Engineer, General Aviation & Rotorcraft Section, International Validation Branch, FAA, 901 Locust, Room 301, Kansas City, MO 64106; phone: (816) 329-4165; fax: (816) 329-4090; email: jim.rutherford@faa.gov.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain serial-numbered (S/N) Schempp-Hirth Flugzeugbau GmbH Model Duo Discus and Duo Discus T gliders. The NPRM published in the Federal Register on October 21, 2021 (86 FR 58228). 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 2020-0233, dated October 27, 2020 (referred to after this as “the MCAI”), to address the unsafe condition on certain S/N Schempp-Hirth Flugzeugbau GmbH Model Duo Discus, Duo Discus C, and Duo Discus T gliders. The MCAI states:

Occurrences were reported of experiencing jerky extension of the airbrakes at very high air speeds, in some cases of which the airbrake blades interlocked. An increasing number of age-related damage was observed on a specific version (22 mm plastic bushes) of the airbrake end-stops.

This condition, if not corrected, could lead to blockage of the airbrakes, possibly resulting in reduced control of the (powered) sailplane.

To address this potential unsafe condition, Schempp-Hirth issued the applicable [technical note] TN (original issue) to provide instructions to replace the affected parts with a new version bushing, made of better material.

Since [EASA planned AD] PAD 20-119 was issued, it was discovered that early s/n sailplanes were equipped with a single metal end stop per airbrake. The applicable TN was revised accordingly. The PAD was revised to include those metal end stops in the definition of `affected part' to ensure these are inspected.

For the reasons described above, this [EASA] AD requires replacement of certain affected parts with serviceable parts. For other affected parts, this [EASA] AD requires a one-time inspection for sufficient overlap and, depending on findings, accomplishment of applicable corrective action(s). This [EASA] AD also prohibits (re)installation of affected parts.

You may examine the MCAI in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0878.

The FAA received no comments on the NPRM or on the determination of the costs.

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 referenced above. The FAA reviewed the relevant data and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. This AD is adopted as proposed in the NPRM.

The FAA reviewed Schempp-Hirth Flugzeugbau GmbH Working Instructions for Technical Note 890-16 rev1 and Technical Note 396-20 rev1 action 1, dated September 18, 2020. The service information contains procedures for replacing each air brake end stop plastic bushing (22 mm) with an air brake end stop plastic bushing (32 mm). The FAA also reviewed Schempp-Hirth Flugzeugbau GmbH Working Instructions for Technical Note 396-20 rev1 action 2, dated September 18, 2020. The service information contains procedures for inspecting each single air brake metal end stop for overlap. 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.

The MCAI applies to Schempp-Hirth Flugzeugbau GmbH Model Duo Discus C gliders, and this AD does not because this model does not have an FAA type certificate.

The MCAI allows credit for modifications done prior to the effective date of the EASA AD in accordance with the original issue of Schempp-Hirth TN 396-20/TN 890-16, but this AD does not provide such credit.

The MCAI prohibits installation of air brake end stop plastic bushings (22 mm) after a glider has been modified with an air brake end stop plastic bushing (32 mm). This AD prohibits installation of air brake end stop plastic bushings (22 mm) as of the effective date of this AD.

The FAA estimates that this AD affects 27 gliders of U.S. registry.

The FAA estimates the following costs to comply with this AD:

The FAA estimates the following costs to do any necessary repairs that would be required based on the results of the inspection. The FAA has no way of determining the number of gliders that might need these repairs:

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.

This AD will not have federalism implications under Executive Order 13132. This AD will 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 AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Will not affect intrastate aviation in Alaska, and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

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