AD 2009-04-08

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) issued 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:

The Luftfahrt-Bundesamt received a report from the Grob Company that a bolt in the airbrake control was found failed during a pre- flight inspection on a G 103C TWIN III ACRO. During an extensive investigation (metallurgical investigation) a double sided fatigue crack was found as root cause. As the bolt is insignificantly stressed by cyclic bending the crack was probably caused by mean stress supported by a bolt torque exceeding the limit.
The actions specified by this airworthiness directive are intended to prevent further bolt cracking which can result in airbrake as well as elevator failure (elevator control is on the same pedestal) and reduced controllability of the power glider.

We are issuing this AD to require actions to correct the unsafe condition on these products.

Final rule.

2009-04-08 BURKHART GROB LUFT--UND RAUMFAHRT GmbH & CO KG: Amendment 39-15814; Docket No. FAA-2008-1078; Directorate Identifier 2008-CE- 051-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective March 31, 2009.

Affected ADs

(b) None.

Applicability

(c) This AD applies to the following models and serial numbers (SNs) gliders, certificated in any category:
(1) G103 TWIN II, SNs 3730 through 3878;
(2) G103A TWIN II ACRO, SNs 3730 through 34078 (K);
(3) G103C TWIN III ACRO, SNs 34101 through 34203; and
(4) G 103 C TWIN III SL, SNs 35001 through 35051.

Subject

(d) Air Transport Association of America (ATA) Code 27: Flight Controls.

Reason

(e) The mandatory continuing airworthiness information (MCAI) states:

"The Luftfahrt-Bundesamt received a report from the Grob Company that a bolt in the airbrake control was found failed during a pre-flight inspection on a G 103C TWIN III ACRO. During an extensive investigation (metallurgical investigation) a double sided fatigue crack was found as root cause. As the bolt is insignificantly stressed by cyclic bending the crack was probably caused by mean stress supported by a bolt torque exceeding the limit.
"The actions specified by this airworthiness directive are intended to prevent further bolt cracking which can result in airbrake as well as elevator failure (elevator control is on the same pedestal) and reduced controllability of the power glider.''

The MCAI requires replacement of bolt LN9037-M6x60 from the airbrake bell crank 103B-4437 with a new bolt with a new locking nut and tightening the bolt to a specific torque; check of all parts of the airbrake bell crank and the attachment parts for any damage and replacement of any damaged parts; check of the airbrake locking force of the left-hand and right-hand wing for a specific force value range and that the locking is clearly noticeable; and check of the airbrake locking force at the operating lever in the front cockpit with the wings rigged for a specific force value range.

Actions and Compliance

(f) Unless already done, within 60 days after March 31, 2009 (the effective date of this AD), do the following actions following Grob Aerospace Service Bulletin No. MSB 315-76/1 and No. 869-27/1 (same document), dated June 23, 2008:
(1) Remove bolt LN9037-M6x60 from the airbrake bell crank 103B- 4437 and install a new bolt LN9037-M6x60 with the new locking nut LN9348-M6 and torque the bolt to 6.4 Nm (4.7 lbs.ft).
(2) Inspect all parts of the airbrake bell crank including the attachment parts for any damage and, before further flight, replace any damaged parts.
(3) Inspect the airbrake locking force of the left-hand (LH) and right-hand (RH) wing using a spring balance. The force must be equal for the LH and RH wing (guidance value: 10 2 daN, (22.5 4.5 lbs)) and the locking must be clearly noticeable.
(4) Inspect the airbrake locking force at the operating lever in the front cockpit with the wings rigged. The guidance value is 10 2 daN, (22.5 4.5 lbs). It must not exceed 15-20 daN (33.7-45.0 lbs).

FAA AD Differences

Note: This AD differs from the MCAI and/or service information as follows: No differences.

Other FAA AD Provisions

(g) The following provisions also apply to this AD:
(1) Alternative Methods of Compliance (AMOCs): The Manager, Standards Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Greg Davison, Glider Program Manager, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4130; fax: (816) 329-4090. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.
(2) Airworthy Product: For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service.
(3) Reporting Requirements: For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120-0056.

Related Information

(h) Refer to MCAI Federal Republic of Germany Luftfahrt- Bundesamt AD D-2008-231, dated July 11, 2008; and AD D-2008-232, dated July 11, 2008; and Grob Aerospace Service Bulletin No. MSB 315-76/1 and No. 869-27/1 (same document), dated June 23, 2008, for related information.

Material Incorporated by Reference

(i) You must use Grob Aerospace Service Bulletin No. MSB 315-76/ 1 and No. 869-27/1 (same document), dated June 23, 2008, to do the actions required by this AD, unless the AD specifies otherwise.
(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact GROB Luft-und Raumfahrt, Lettenbachstrasse 9, D-86874 Tussenhausen- Mattsies, Germany; telephone: + 011 49 8268 998139; facsimile: + 011 49 8268 998200; E-mail: productsupport@grob-aerospace.de; Internet: http://www.grob-aerospace.net.
(3) You may review copies of the service information incorporated by reference for this AD at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Kansas City, Missouri 64106. For information on the availability of this material at the Central Region, call (816) 329-3768.
(4) You may also review copies of the service information incorporated by reference for this AD at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to: http:// www.archives.gov/federal_register/code_of_federal_regulations/ ibr_locations.html.

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM was published in the Federal Register on October 9, 2008 (73 FR 59571). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI states:

The Luftfahrt-Bundesamt received a report from the Grob Company that a bolt in the airbrake control was found failed during a pre- flight inspection on a G 103C TWIN III ACRO. During an extensive investigation (metallurgical investigation) a double sided fatigue crack was found as root cause. As the bolt is insignificantly stressed by cyclic bending the crack was probably caused by mean stress supported by a bolt torque exceeding the limit.
The actions specified by this airworthiness directive are intended to prevent further bolt cracking which can result in airbrake as well as elevator failure (elevator control is on the samepedestal) and reduced controllability of the power glider.

Comments

We gave the public the opportunity to participate in developing this AD. We received no comments on the NPRM or on the determination of the cost to the public.

Conclusion

We reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed.

Differences Between This AD and the MCAI or Service Information

We have reviewed the MCAI and related service information and, in general, agree with their substance. But we might have found it necessary to use different words from those in the MCAI to ensure the AD is clear for U.S. operators and is enforceable. In making these changes, we do not intend to differ substantively from the information provided in the MCAI and related service information.
We might also have required different actions in this AD from those in the MCAI in order to follow FAA policies. Any such differences are highlighted in a Note within the AD.

Costs of Compliance

Based on the service information, we estimate that this AD will affect 129 products of U.S. registry. We also estimate that it will take about 1 work-hour per product to comply with basic requirements of this AD. The average labor rate is $80 per work-hour.

Required parts will cost about $15 per product.
Based on these figures, we estimate the cost of this AD to the U.S. operators to be $12,255 or $95 per product.

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.
We are 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

We determined that 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) Is not a "significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 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.
We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD Docket.

Examining the AD Docket

You may examine the AD docket on the Internet at http: // www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the NPRM, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone (800) 647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

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

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by adding the following new AD: