Document ID: FAA-2007-28435-0016
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: GROB-WERKE GMBH and CO KG Models G102 ASTIR CS, G102 CLUB ASTIR III, G102 CLUB ASTIR IIIb, and G102 STANDARD ASTIR III Gliders
Posted Date: 2011-01-10T05:00Z

[Federal Register Volume 76, Number 6 (Monday, January 10, 2011)]
[Rules and Regulations]
[Pages 1342-1346]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-32753]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28435 Directorate Identifier 2007-CE-054-AD; 
Amendment 39-16556; AD 2011-01-03]
RIN 2120-AA64

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.

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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: +49 (0) 8268 998 139; fax: +49 
(0) 8268 998 200; E-mail: aircraft.com">productsupport@grob-aircraft.com; 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: (816) 329-4165; fax: (816) 329-4090.
     Greg Davison, Aerospace Engineer, FAA, Small Airplane 
Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; 
telephone: (816) 329-4130; fax: (816) 329-4090.

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.

[[Page 1343]]

    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

[[Page 1344]]

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: 
+49 7353 2243; fax: +49 7353 3096; e-mail: H.Lindner@t-online.de; 
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 (505) 269-8234; e-mail: Robertmudd1u@aol.com. 
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

[[Page 1345]]

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 (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 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  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.

[[Page 1346]]

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: (816) 329-4165; fax: (816) 329-4090; or
    (ii) Greg Davison, Aerospace Engineer, FAA, Small Airplane 
Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; 
telephone: (816) 329-4130; fax: (816) 329-4090.
    (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: +49 (0) 8268 998 139; fax: 
+49 (0) 8268 998 200; E-mail: aircraft.com">productsupport@grob-aircraft.com; 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 (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.

    Issued in Kansas City, Missouri, on December 21, 2010.
Earl Lawrence,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2010-32753 Filed 1-7-11; 8:45 am]
BILLING CODE 4910-13-P