2010-32753. Airworthiness Directives; GROB-WERKE GMBH & CO KG Models G102 ASTIR CS, G102 CLUB ASTIR III, G102 CLUB ASTIR IIIb, and G102 STANDARD ASTIR III Gliders

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule.

SUMMARY:

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:

As a result of the replacement action of the G 103 TWIN ASTIR spar spigot assemblies, the Gliding Federation of Australia issued a directive to inspect the similar main spigots of single-seater sailplanes.

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

DATES:

This AD becomes effective February 14, 2011.

On February 14, 2011, the Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD.

ADDRESSES:

You may examine the AD docket on the Internet at http://www.regulations.gov or in person at Document Management Facility, U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.

For service information identified in this AD, contact Grob Aircraft; Lettenbachstr. 9; Tussenhausen-Mattsies; Head of Customer Service & Support, Germany; telephone: [phone]; fax: [phone]; E-mail: [e-mail]; Web site: http://www.grob-aircraft.com. You may review copies of the referenced service information at the FAA, Small Airplane Directorate, 901 Locust, Kansas City, Missouri 64106. For information on the availability of this material at the FAA, call 816-329-4148.

FOR FURTHER INFORMATION CONTACT ONE OF THE FOLLOWING:

 

• Jim Rutherford, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; fax: [phone].
• Greg Davison, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; fax: [phone].

SUPPLEMENTARY INFORMATION:

Discussion

History of AD Actions

When the State of Design issues MCAI against a product that is certificated for operation in the United States, the FAA evaluates this information and either issues a corresponding U.S. AD or completes a no action required (NAR) form. In 1988, the FAA's Brussels, Belgium office evaluated MCAIs. When the Brussels office determined an AD was necessary, the corresponding Directorate issued an AD for the product. NAR forms were completed by the Brussels office. When a NAR form was completed, the Directorates did not always receive a copy since they were not required to take action.

The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority for Germany, issued AD 88-176 Grob, dated August 15, 1988, to apply to the GROB-WERKE GMBH & CO KG G103 twin-seat gliders. That AD required inspection and replacement of the spar spigot assembly to prevent fatigue failure of the spigot. The FAA issued AD 90-02-09 (55 FR 269, January 4, 1990), effective February 5, 1990, to mandate replacement of the spigot assembly for the G103 twin-seat versions of the glider.

The LBA issued 91-5/2 Grob, dated February 1, 1991, to apply to the GROB-WERKE GMBH & CO KG G102 single-seat gliders. The MCAI states:

As a result of the replacement action of the G 103 TWIN ASTIR spar spigot assemblies, the Gliding Federation of Australia issued a directive to inspect the similar main spigots of single-seater sailplanes.

The MCAI requires you to inspect the wing main spigot assembly before the next flight and replace it on the G102 single-seat gliders. You may obtain further information by examining the MCAI in the AD docket.

The FAA inadvertently did not issue an AD on the single-seat versions at the time the LBA issued AD 91-5/2 Grob. The FAA finds no AD or NAR information to correspond with German AD 91-5/2 Grob from that time period.

In 1997/1998, the responsibility to evaluate MCAIs transferred from Brussels to the Directorates. The Directorates assimilated all of the Brussels information into the Directorate information, identifying if ADs were issued, if NAR forms were completed, or if neither action was taken. During this time, the Small Airplane Directorate issued a total of 310 AD actions in fiscal year (FY) 1998. This was an increase of 79 percent over the 173 total actions issued in FY-97, and a 121 percent increase over the 140 total actions issued in FY-96. This workload increase contributed to the FAA not identifying the German AD 91-5/2 Grob as an item without a U.S. AD or NAR correspondence associated with it.

In early 2005, through discussions with Grob representatives, we determined that we needed to address the unsafe condition for the G102 single-seat versions of the glider in the United States.

After further review of the data, we determined AD action is necessary to correct an unsafe condition on the G102 versions of the glider for the following reasons:

• Cracks have been found on the wing spigot assemblies installed on the G102 single-seat gliders. Several of these cracks were internal to the spigot and were not visually detectable until the component failed.
• Cracks in the wing spigot assembly pin-to-plate interface could cause the spar spigot to fail with little or no warning.
• The manufacturer has maintained their position that the original wing spigot assembly design is inadequate to sustain the structure for the operational service life of the aircraft.

Consequently, 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. The NPRM was published in the Federal Register on July 30, 2007 (72 FR 41466). That NPRM proposed to correct an unsafe condition for the specified products.

The public responded to this published notice, and the FAA appreciates the numerous comments submitted for consideration in addressing this important airworthiness issue. Our comment disposition took a considerable amount of time researching and organizing data to adequately address those comments. Through the comment disposition process, we found that the material required for the repair was not available in the United States and an undue cost burden would have been placed on operators to get the repair material from Germany. We coordinated the use of an alternate resin/hardener for the repair that is available in the United States.

History of the Unsafe Condition

The original design of the spar spigot utilizes a steel pin with a welded steel plate adjacently attached. The welded interface between the pin and the plate is the critical area subjected to structural fatigue. This mode of failure has resulted in a redesign (design enhancement) of the spar spigot assembly that uses no welds and has additional filleting to increase part strength, durability, and enhances reliability. Therefore, based on the potential severity of failure, the FAA determined that the originally designed spar spigots should be replaced.

When Grob Luft- und Raumfahrt (Grob) issued Service Bulletin TM 306-29; TM 320-5, issue date: October 11, 1990, there were no reports of crack occurrences in Germany. However, Grob implemented this measure to ensure the safety of their gliders.

The Gliding Federation of Australia's Airworthiness Directive number 370, Issue 2, dated January 10, 1991, stated a large percentage of their single-seat G102 series gliders, at that time, were found to contain cracks. The exact figure for the number of occurrences is not known. The results of one repair shop in Australia revealed that of 12 spigot assemblies replaced on the single-seat models, 7 were found to have cracks. Several of these cracks were internal to the spigot. Internal cracks located in this area would not be visually detectable until the component failed.

The LBA issued AD 91-5/2 Grob to mandate the action from Grob's service bulletin; this action was later adopted in Europe, New Zealand, Canada, and Brazil.

After evaluating the crack findings from the Gliding Federation of Australia, the position of Grob's technical advisors, and the actions of the German airworthiness authority, we determined it necessary to issue this AD action.

Comments

We gave the public the opportunity to participate in developing this AD. We considered the comments received.

Comment Issue No. 1: Proposed AD Lacks Supporting Evidence

Cindy Brickner, John H. Campbell, David Forrest, Hartley L. Falbaum, Philippe C. Marchal, Bruce Stobbe, and the Soaring Society of America (SSA) cite lack of rationale to mandate the unconditional replacement of the wing main spigot assembly. The spar spigot assembly is serviceable, and there is no evidence or history of problems for the G102 series gliders. We infer the commenters want us to withdraw the NPRM.

We disagree with the comment. Because a failure has not occurred is no justification that imminent failure to this critical structure could not happen. The Grob Luft- und Raumfahrt Service Bulletin TM 306-29; TM 320-5, issue date: October 11, 1990, states that inspection and replacement of the spar spigot assembly was due to an increased occurrence of cracks found on Grob's single-seat Astir series that operated in Australia. The Gliding Federation of Australia has identified at least nine occurrences of cracks found during the inspection of the single-seat gliders. Consequently, the occurrences of cracked pins resulted in Australia issuing AD 370, Issue 2, dated January 10, 1991.

Although a critical failure of the spar spigot assembly has not been documented in the United States, Grob maintains that the original design of the wing spar spigot assembly is inadequate to meet the airframe life limits and can not be repaired as a long-term corrective action.

We are not changing the final rule AD action as a result of this comment.

Comment Issue No. 2: Request Repetitive Inspections Instead of a Calendar-Based Replacement

Cindy Brickner, Robert DeFabio, David M. Forrest, Philippe C. Marchal, Bruce Stobbe, and the SSA, request allowing frequent or annual inspections in lieu of the required wing main spigot replacement citing that inspections would provide adequate warning before spigot failure.

We disagree with the comment. Based on information from the manufacturer, the original design of the wing main spigot assembly uses materials and/or a configuration deemed inadequate to sustain the structure for the operation and service life of the aircraft.

The critical failure mode of the wing spar spigot assembly is at the weld of the steel pin-to-plate interface. Cracks in these welds could cause the spar spigot to fail with little or no warning. If this joint fails, then failure of the wing spar could occur. Considering this situation, using an inspection to determine airworthiness is not a comprehensive method for ensuring the safety of the airframe.

The spar spigot assembly is based on a safe-life design philosophy. A safe-life design structure must be able to sustain a certain number of events such as flights, landings, and/or flight hours with a low probability that the strength will degrade below its design ultimate value due to fatigue cracking. In this type of structural design, there is no redundant or backup structural element to retain the structure's residual strength after the failure or partial failure of the principle structural element: the pin-to-plate interface.

From the FAA's perspective, in a safe-life designed structure, the development of a detectable crack is considered fatigue failure. Since a safe-life evaluation usually does not include demonstration of crack growth rates or residual strength capability, we assume that the development of a detectable crack may result in a catastrophic failure of the structure. The replacement spar spigot assembly has been redesigned to be more robust due to the manufacturing process used along with additional filleting which enhances fatigue resistance.

The new design also removes the critical failure mode and the requirements for weld inspections. Therefore, at Grob's discretion, a design enhancement, not a work-around solution, was implemented in order to increase the safety of this structural interface.

We are not changing the final rule AD action as a result of this comment.

Comment Issue No. 3: The German MCAI Is Less Severe Than the Proposed AD

Hartley L. Falbaum and Bruce Stobbe interpret that the German AD allows cracks to be blended out and the parts to remain in service. Consequently, there is adequate warning prior to failure. They request an alternative method of compliance (AMOC) to the requirements of the proposed AD.

We disagree with the comment and the interpretation. The MCAI clearly states the requirements to inspect and replace the wing main spigot assembly. The Grob Luft- und Raumfahrt Service Bulletin TM 306-29; TM 320-5, issue date: October 11, 1990, authorizes crack removal by blending based on specific, detailed criteria. Regardless, if the criterion is or is not met, the wing main spigot assembly must be replaced within a given time. Finally, cracks in the welds of the pin-to-plate interface could cause the spar spigot to fail with little or no warning.

We are not changing this final rule AD action as a result of this comment.

Comment Issue No. 4: Limited Number of Repair Facilities

Cindy Brickner, John H. Campbell, Robert DeFabio, David Forrest, Hartley L. Falbaum, Bruce Stobbe, and the SSA express concerns that an adequate repair facility may not be available to do the repair.

We partially agree with this comment. The closing of Grob's repair facility in Bluffton, Ohio, leaves few repair facilities with direct experience in doing this work. However, 14 CFR part 65 provides that an appropriately rated mechanic with an inspection authorization or an appropriately rated mechanic under the oversight of a mechanic with an inspection authorization is approved for this level of repair. We are aware of the cost and travel impacts of this AD on the gliding community. However, this does not diminish the need to do the repair, and a glider that has not had the replacement of the wing main spigot assembly has a corresponding reduction in its value.

We are not changing the final rule AD action as a result of this comment.

Comment Issue No. 5: Risk With the Proposed Repair

Robert DeFabio, Hartley L. Falbaum, Philippe C. Marchal, and Bruce Stobbe express concerns that fewer repair stations with less experienced personnel to do the repair will create a greater risk than the one the glider is currently exposed to.

We disagree with the comment. We issued AD 90-02-09, effective February 5, 1990, for the twin-seat version of the glider, which mandated replacement of the spigot assembly. Approximately 120 of the repairs have been made for this AD, all without incident or failure attributed to this rework. Further, the mandatory repair implemented worldwide has had no known failure.

We are not changing the final rule AD action as a result of this comment.

Comment Issue No. 6: Parts, Tools, and Repair Skills Needed May Not Be Available

Cindy Brickner and David Forrest express concern that since the closing of Grob's repair facility in Ohio, the parts, tools, and repair skills needed may not be available to do the proposed AD.

We disagree with the comment. Parts are available for the replacement of the wing main spigot assembly from Fiberglas-technik, Rudolph Linder GmbH & Co. KG; Steige 3, 88487 Walpertshofen; telephone: [phone]; fax: [phone]; e-mail: [e-mail]; Internet: http://www.LTB-Lindner.com. There is also a limited supply of parts from Composite Aircraft Repair, P.O. Box 2010, Moriarty, New Mexico 87035; telephone [phone]; e-mail: [e-mail]. An appropriately rated mechanic with an inspection authorization or an appropriately rated mechanic under the oversight of a mechanic with an inspection authorization is approved to do this repair. Also, approximately 120 of the repairs have been made for a similar AD, all without incident or failure attributed to this rework. Further, the mandatory repair implemented worldwide has had no known failure.

After the NPRM was issued, we found that the material required for the repair was not available in the United States and an undue cost burden would have been placed on operators to get the repair material from Germany. This final rule AD action adds Grob Aircraft Repair Instructions No. RI-GROB-001, dated May 14, 2009, that lists an alternate resin/hardener available in the United States.

We are not changing the final rule AD action as a result of this comment.

Comment Issue No. 7: Extend All Compliance Times To Allow Time To Get Parts and Schedule Spar Spigot Assembly Replacement

The SSA requests FAA extend all compliance times to allow time to procure parts and schedule replacement of the wing main spigot assembly with a qualified repair facility.

The FAA agrees with the SSA's proposal to extend the compliance time for the initial inspection from 10 to 25 hours time-in-service after the effective date of the AD and, if no cracks are found, increase the replacement time for the wing main spigot assembly from 12 to 15 months after the effective date of the AD.

Comment Issue No. 8: The Design Defect Found on the Twin-Seat Glider Is Not Applicable to the Single-Seat Glider

John H. Campbell writes that the perceived defect is centered on the twin-seat version of the glider. This perceived defect should not include the single-seat version of this glider. He also writes that the twin-seat glider is certificated under the aerobatic category; the single-seat glider is certificated under the utility category. We infer that, based on the design and operation of the affected single-seat glider, the commenter wants the proposed AD withdrawn.

We disagree with this comment. The fact that the single-seat glider is lighter and certificated in the utility category is not relevant. The original design of the wing spar spigot assembly of the single-seat and twin-seat gliders is insufficient to meet the airframe life limits. The type design of the G102 series gliders is similar to the type design of the G103 series gliders. As a result, the German airworthiness authority issued its ADs. We concur with Grob and the German airworthiness authority that this is a required AD action.

We are not changing the final rule AD action as a result of this comment.

Comment Issue No. 9: Withdraw the Proposed AD

John Campbell writes that this issue was addressed more than 20 years ago and that many Grob sailplanes now have thousands of flight hours. The MCAI statement from the manufacturer in the NPRM is based on a decision made in Australia. Campbell asks why the FAA is addressing this now and what prompted action on this issue. He notes that the gliders made in the 1980s are bargain investments. The cost to repair is a large part of the total value of the glider. Although no specific change is requested, based on the comment, we infer that the commenter wants the NPRM withdrawn.

For unknown reasons, the FAA did not issue an AD on the single-seat versions of these gliders at the time the German airworthiness authority issued its AD. Further, a review of our records finds no explanation for the delay in addressing this issue. Nevertheless, a safety issue exists that must be addressed.

The Gliding Federation of Australia noted that in Australia, the single-seat G102 series gliders, which have a similar type design to the twin-seat versions, had reports of cracking in the welds of the pins. Consequently, the occurrences of cracked pins in several gliders resulted in Australia issuing AD 370, Issue: 2, dated January 10, 1991.

We recognize that doing this AD to maintain the glider's airworthiness is a financial burden. However, a glider that has not had the replacement of the wing main spigot assembly has a corresponding reduction in its value.

We are not changing the final rule AD action as a result of this comment.

Conclusion

We reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.

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

We estimate that this AD will affect 79 products of U.S. registry. We also estimate that it will take about 25 work-hours per product to comply with the basic requirements of this AD. The average labor rate is $85 per work-hour. Required parts will cost about $840 per product.

Based on these figures, we estimate the cost of this AD to the U.S. operators to be $234,235 or $2,965 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 [phone]) 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 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 AD:

2011-01-03 GROB-WERKE GMBH & CO KG: Amendment 39-16556; Docket No. FAA-2007-28435; Directorate Identifier 2007-CE-054-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective February 14, 2011.

Affected ADs

(b) None.

Applicability

(c) This AD applies to the GROB-WERKE GMBH & CO KG gliders Model G102 ASTIR CS, serial numbers (SNs) 1001 through 1536; Model G102 CLUB ASTIR III, SNs 5501 (suffix C) through 5652 (suffix C); Model G102 CLUB ASTIR IIIb, SNs 5501 (suffix Cb) through 5652 (suffix Cb); and Model G102 STANDARD ASTIR III, SNs 5501 (suffix S) through 5652 (suffix S), that are:

(1) Equipped with any wing spar spigot assembly that has not been replaced following Grob Luft-und Raumfahrt Service Bulletin TM 306-29; TM 320-5, issue date: October 11, 1990; and

(2) Are certificated in any category.

Subject

(d) Air Transport Association of America (ATA) Code 57: Wings.

Reason

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

As a result of the replacement action of the G 103 TWIN ASTIR spar spigot assemblies, the Gliding Federation of Australia issued a directive to inspect the similar main spigots of single-seater sailplanes.

The MCAI requires you to inspect the wing main spigot assembly before the next flight and replace it.

Actions and Compliance

(f) Unless already done, do the following actions:

(1) Within the next 25 hours time-in-service (TIS) after February 14, 2011 (the effective date of this AD), inspect both wing spar spigot assemblies for cracks using a dye-penetrant or magnetic-particle method following Grob Luft- und Raumfahrt Service Bulletin TM 306-29; TM 320-5, issue date: October 11, 1990. The use of the magnification method is prohibited.

Note 1:

If dye-penetrant method is used, great care should be exercised when cleaning and/or etching the surfaces and interpreting surface faults.

(2) Replace the wing main spigot assembly following Grob Luft- und Raumfahrt Service Bulletin TM 306-29; TM 320-5, issue date: October 11, 1990; and Grob Aircraft Repair Instructions No. RI-GROB-001, dated May 14, 2009, using whichever of the following compliance times that apply:

(i) If cracks are found during the inspection required in paragraph (f)(1) of this AD, before further flight; or

(ii) If no cracks are found during the inspection required in paragraph (f)(1) of this AD, within the next 15 months after February 14, 2011 (the effective date of this AD).

FAA AD Differences

Note 2:

This AD differs from the MCAI and/or service information as follows:

(1) The MCAI compliance time required the wing main spigot assembly to be inspected before the next flight and replacement of the wing spar spigot assembly no later than December 31, 1992. This AD requires inspection within the next 25 hours TIS after February 14, 2011 (the effective date of this AD), and replacement prior to further flight after the inspection where cracks are found or 15 months after February 14, 2011 (the effective date of this AD), if no cracks are found.

(2) In lieu of authorizing a 10x magnifier for inspection as specified in the MCAI, this AD requires you use either a dye-penetrant or magnetic-particle inspection method.

(3) After the notice of proposed rulemaking (NPRM) was issued, we found that the material required for the repair was not available in the United States and an undue cost burden would have been placed on operators to get the repair material from Germany. This AD adds Grob Aircraft Repair Instructions No. RI-GROB-001, dated May 14, 2009. This repair instruction lists an alternate resin/hardener that is available in the United States.

Other FAA AD Provisions

(g) The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, Standards Staff, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. 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. Send information to ATTN of one of the following individuals:

(i) Jim Rutherford, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; fax: [phone]; or

(ii) Greg Davison, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; fax: [phone].

(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, a Federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to be approximately 5 minutes per response, including the time for reviewing instructions, completing and reviewing the collection of information. All responses to this collection of information are mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the burden should be directed to the FAA at: 800 Independence Ave., SW., Washington, DC 20591, Attn: Information Collection Clearance Officer, AES-200.

Related Information

(h) Refer to MCAI Federal Republic of Germany Luftfahrt-Bundesamt AD 91-5/2 Grob, dated February 1, 1991; Grob Luft- und Raumfahrt Service Bulletin TM 306-29; TM 320-5, issue date: October 11, 1990; and Grob Aircraft Repair Instructions No. RI-GROB-001, dated May 14, 2009, for related information.

Material Incorporated by Reference

(i) You must use Grob Luft-und Raumfahrt Service Bulletin TM 306-29; TM 320-5, issue date: October 11, 1990; and Grob Aircraft Repair Instructions No. RI-GROB-001, dated May 14, 2009, 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 Aircraft; Lettenbachstr. 9; Tussenhausen-Mattsies; Head of Customer Service & Support, Germany; telephone: [phone]; fax: [phone]; E-mail: [e-mail]; Web site: http://www.grob-aircraft.com.

(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 [phone].

(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 [phone], or go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

Issued in Kansas City, Missouri, on December 21, 2010.

Earl Lawrence,

Manager, Small Airplane Directorate, Aircraft Certification Service.