2021-22680. Airworthiness Directives; Schempp-Hirth Flugzeugbau GmbH Gliders

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Schempp-Hirth Flugzeugbau GmbH Model Duo Discus and Duo Discus T gliders. This proposed 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 jerky extension of the air brakes at very high air speeds, including cases where the air brake blades interlock. This proposed AD would require replacing certain air brake end stop bushings, inspecting certain other air brake end stops, and repairing if necessary. 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 December 6, 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: [phone].

• 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 Schempp-Hirth Flugzeugbau GmbH, Krebenstrasse 25, 73230 Kirchheim/Teck, Germany; phone: [phone]; fax: [phone]; email: [e-mail] ; website: https://www.schempp-hirth.com. You may view this referenced 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 [phone].

Examining the AD Docket

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

Jim Rutherford, Aviation Safety Engineer, General Aviation & Rotorcraft Section, International Validation Branch, FAA, 901 Locust, Room 301, Kansas City, MO 64106; phone: [phone]; fax: [phone]; email: [e-mail].

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 ADDRESSES . Include “Docket No. FAA-2021-0878; Project Identifier MCAI-2020-01460-G” 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 this 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 NPRM.

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 Jim Rutherford, Aviation Safety Engineer, FAA, General Aviation & Rotorcraft Section, International Validation Branch, FAA, 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 2020-0233, dated October 27, 2020 (referred to after this as “the MCAI”), to address an unsafe condition on certain serial-numbered (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.

Related Service Information Under 1 CFR Part 51

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.

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, except as described under “Differences Between this Proposed AD and the MCAI.” This proposed AD would also require repairing any single air brake metal end stop with insufficient overlap.

Differences Between This Proposed AD and the MCAI

The MCAI applies to Schempp-Hirth Flugzeugbau GmbH Model Duo Discus C gliders, and this proposed AD would 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 proposed AD would 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 proposed AD would prohibit installation of air brake end stop plastic bushings (22 mm) as of the effective date of this AD.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 27 gliders of U.S. registry.

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

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Replace plastic end stop bushings	4 work-hours × $85 per hour = $340	$150	$490	Up to $13,230 (depending on number of gliders with plastic end stop bushings).
Inspect metal end stops	1 work-hour × $85 per hour = $85	0	85	Up to $2,295 (depending on number of gliders with metal end stops).

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

On-Condition Costs

Action	Labor cost	Parts cost	Cost per product
Repair metal end stops	4 work-hours × $85 per hour = $340	$150	$490

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.

§ 39.13

[Amended]

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

Schempp-Hirth Flugzeugbau GmbH: Docket No. FAA-2021-0878; Project Identifier MCAI-2020-01460-G.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by December 6, 2021.

(b) Affected ADs

None.

(c) Applicability

This AD applies to the Schempp-Hirth Flugzeugbau GmbH gliders identified in paragraphs (c)(1) and (2) of this AD, certificated in any category.

(1) Model Duo Discus gliders, serial number (S/N) 1 through 541 inclusive, except S/N 534.

(2) Model Duo Discus T gliders, S/N 1 through 174 inclusive.

(d) Subject

Joint Aircraft System Component (JASC) Code 2760, Drag Control System.

(e) Unsafe Condition

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 jerky extension of the air brakes at very high air speeds, including cases where the air brake blades interlock. The FAA is issuing this AD to prevent and correct damage of the airbrake end-stops. The unsafe condition, if not addressed, could result in blockage of the air brakes and reduced control of the glider.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Required Actions

(1) For gliders with air brake end stop plastic bushings (22 mm) installed: Within 3 months after the effective date of this AD, replace each air brake end stop plastic bushing (22 mm) with an air brake end stop plastic bushing (32 mm) in accordance with Schempp-Hirth Flugzeugbau GmbH Working Instructions for Technical Note 890-16 rev1 and Technical Note 396-20 rev1 action 1, dated September 18, 2020.

(2) For gliders with single air brake metal end stops installed: Within 3 months after the effective date of this AD, inspect each single air brake metal end stop for overlap in accordance with Schempp-Hirth Flugzeugbau GmbH Working Instructions for Technical Note 396-20 rev1 action 2, dated September 18, 2020. If there is insufficient overlap, before further flight, repair using a method approved by the FAA or the European Union Aviation Safety Agency (EASA).

(h) Parts Installation Prohibition

As of the effective date of this AD, do not install an air brake end stop plastic bushing (22 mm) on any glider.

(i) Alternative Methods of Compliance (AMOCs)

(1) The Manager, International Validation Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the International Validation Branch, send it to the attention of the person identified in paragraph (j)(1) of this AD or email: [e-mail].

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.

(j) Related Information

(1) For more information about this AD, contact Jim Rutherford, Aviation Safety Engineer, General Aviation & Rotorcraft Section, International Validation Branch, FAA, 901 Locust, Room 301, Kansas City, MO 64106; phone: [phone]; fax: [phone]; email: [e-mail].

(2) Refer to EASA AD 2020-0233, dated October 27, 2020, for more information. You may examine the EASA AD in the AD docket at https://www.regulations.gov by searching for and locating it in Docket No. FAA-2021-0878.

(3) For service information identified in this AD, contact Schempp-Hirth Flugzeugbau GmbH, Krebenstrasse 25, 73230 Kirchheim/Teck, Germany; phone: [phone]; fax: [phone]; email: [e-mail] ; website: https://www.schempp-hirth.com. You may view this referenced 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 [phone].

Issued on October 8, 2021.

Gaetano A. Sciortino,

Deputy Director for Strategic Initiatives, Compliance & Airworthiness Division, Aircraft Certification Service.