[Federal Register Volume 63, Number 227 (Wednesday, November 25, 1998)]
[Rules and Regulations]
[Pages 65048-65050]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-31317]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-CE-40-AD; Amendment 39-10905; AD 98-24-20]
RIN 2120-AA64


Airworthiness Directives; Grob Luft-und Raumfahrt, GmbH Models G 
109 and G 109B Sailplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to certain Grob Luft-und Raumfahrt (Grob) Models G 109 and G 
109B sailplanes. This AD requires inspecting the radius of the landing 
gear retaining bars, installing additional supportive parts, and 
replacing the retaining bars if the retaining bars' chamfer radius is 
less than 3.0 millimeters (mm). This AD also requires inspecting the 
landing gear legs for cracks and proper thickness, and either polishing 
out the cracks or replacing the landing gear legs with parts of 
improved design depending on the crack length. This AD is the result of 
mandatory continuing airworthiness information (MCAI) issued by the 
airworthiness authority for Germany. The actions specified by this AD 
are intended to detect and correct fatigue cracking of the landing gear 
legs, which could result in landing gear failure with consequent loss 
of control of the sailplane during landing operations.

DATES: Effective January 9, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 9, 1999.

ADDRESSES: Service information that applies to this AD may be obtained 
from Grob-Werke GmbH & Co. KG, Unternehmensbereich, Burkhart Grob 
Flugzeugbau, Flugplatz Mattsies, 86874 Tussenhausen, Germany. This 
information may also be examined at the Federal Aviation Administration 
(FAA), Central Region, Office of the

[[Page 65049]]

Regional Counsel, Attention: Rules Docket No. 96-CE-40-AD, Room 1558, 
601 E. 12th Street, Kansas City, Missouri 64106; or at the Office of 
the Federal Register, 800 North Capitol Street, NW, suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mr. Mike Kiesov, Aerospace Engineer, 
FAA, Small Airplane Directorate, 1201 Walnut, suite 900, Kansas City, 
Missouri 64106; telephone: (816) 426-6932; facsimile: (816) 426-2169.

SUPPLEMENTARY INFORMATION:

Events Leading to the Issuance of This AD

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to include an AD that would apply to certain Grob G 109 
and G 109B sailplanes was published in the Federal Register as a notice 
of proposed rulemaking (NPRM) on February 19, 1997 (62 FR 7373). The 
NPRM proposed to require inspecting the radius of the landing gear 
retaining bars, installing additional supportive parts, and replacing 
the retaining bars if the retaining bars' chamfer radius is less than 
3.0 mm. The NPRM also proposed to require inspecting the landing gear 
legs for cracks and proper thickness, and either polishing out the 
cracks or replacing the landing gear legs with parts of improved design 
depending on the crack length.
    Accomplishment of the proposed action as specified in the NPRM 
would be required in accordance with Grob Service Bulletin TM 817-39, 
dated January 4, 1994.
    The NPRM was the result of mandatory continuing airworthiness 
information (MCAI) issued by the airworthiness authority for Germany.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposed rule or the FAA's determination of the cost to the public.

The FAA's Determination

    After careful review of all available information related to the 
subject presented above, the FAA has determined that air safety and the 
public interest require the adoption of the rule as proposed except for 
minor editorial corrections. The FAA has determined that these minor 
corrections will not change the meaning of the AD and will not add any 
additional burden upon the public than was already proposed.

Cost Impact

    The FAA estimates that 63 sailplanes in the U.S. registry will be 
affected by this AD.
    The required inspection and modification of the retaining bars will 
take approximately 4 workhours per sailplane (2 workhours per landing 
gear leg) to accomplish, at an average labor rate of approximately $60 
an hour. Parts to accomplish the required modifications cost $90. Based 
on these figures, the total cost impact of this inspection and 
modification on U.S. operators is estimated to be $20,790, or $330 per 
sailplane.
    The initial inspection will take approximately 18 workhours per 
sailplane (9 workhours per landing gear leg) to accomplish, at an 
average labor rate of $60 per hour. Based on these figures, the total 
cost impact of the initial inspection on U.S. operators is estimated to 
be $68,040, or $1,080 per sailplane.
    The above figures only take into account the costs of the initial 
inspection of the landing gear leg and do not take into account costs 
associated with repetitive inspections or any required crack polishing 
or landing gear leg replacement. The FAA has no way of determining the 
number of repetitive inspections each owner/operator of the affected 
sailplanes would incur, or the number of landing gear legs that will be 
found cracked and either need polishing or replacement.

Compliance Time

    The compliance time of this AD is presented in calendar time 
instead of hours time-in-service (TIS). The FAA has determined that a 
calendar time compliance is the most desirable method because the 
unsafe condition of the landing gear legs described by this AD is 
caused by corrosion. Corrosion initiates as a result of sailplane 
operation, but can continue to develop regardless of whether the 
sailplane is in service. In order to assure that the above-referenced 
condition is detected and corrected on all sailplanes within a 
reasonable period of time without inadvertently grounding any 
sailplanes, the FAA is requiring a compliance schedule based upon 
calendar time instead of hours TIS.

Regulatory Impact

    The regulations adopted herein will not have substantial direct 
effects 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. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (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. A copy of the final evaluation prepared for this 
action is contained in the Rules Docket. A copy of it may be obtained 
by contacting the Rules Docket at the location provided under the 
caption ADDRESSES.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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.

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
(AD) to read as follows:

98-24-20  Grob Luft-und Raumfahrt, GMBH: Amendment 39-10905, Docket 
No. 96-CE-40-AD.

    Applicability: Models G 109 and G 109B sailplanes, all serial 
numbers, certificated in any category.

    Note 1: This AD applies to each sailplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For sailplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (d) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.


[[Page 65050]]


    Compliance: Required as indicated in the body of this AD, unless 
already accomplished.
    To detect and correct fatigue cracking of the landing gear legs, 
which could result in landing gear failure with consequent loss of 
control of the sailplane during landing operations, accomplish the 
following:
    (a) For all of the affected sailplanes: Within the next 120 
calendar days after the effective date of this AD, inspect the 
retaining bars chamfer on both landing gear legs for a minimum of 
3.0 millimeters (mm) radius in accordance with the ``Actions'' 
section, paragraph A3, of Grob Service Bulletin (SB) 817-39, dated 
January 4, 1994.
    (1) If the chamfer radius is 3.0 mm or greater, prior to further 
flight, glue a reinforcing plastic strip (part number (P/N) 109-
5000.07) to the retaining bar in accordance with the ``Actions'' 
section, paragraph A4, of Grob SB 817-39, dated January 4, 1994.
    (2) If the chamfer radius is less than 3.0 mm, prior to further 
flight, replace the retaining bar with a new improved design 
retaining bar, P/N 109-5000.02; and install the plastic strip, P/N 
109-5000.07. Accomplish these actions in accordance with the 
``Actions'' section, paragraph A5, of Grob SB 817-39, dated January 
1994.
    (b) For sailplanes that are not equipped with landing gear legs, 
P/N 109B-5001.01/1: Upon the accumulation of 1,000 hours TIS on the 
landing gear leg or within the next 100 hours TIS after the 
effective date of this AD, whichever occurs later, and thereafter at 
intervals not to exceed 500 hours TIS, inspect the landing gear legs 
for cracks (using the magnetic particle or X-ray analysis method) in 
accordance with the ``Actions'' section, paragraph B9, of Grob SB 
817-39, dated January 4, 1994.
    (1) If any crack(s) is found that does not exceed a maximum 
depth of 0.5 millimeters (mm) on each side, prior to further flight, 
polish out the crack(s) in accordance with the ``Actions'' section, 
paragraph B10, of Grob SB 817-39, dated January 4, 1994.
    (2) If after polishing out any crack, as specified in paragraph 
(b)(1) of this AD, the undercarriage thickness is not at least 13 
mm, prior to further flight, replace the cracked landing gear leg 
with a P/N 109B-5001.01/1 landing gear leg, in accordance with the 
``Actions'' section, paragraph B10, of Grob SB 817-39, dated January 
4, 1994.
    (3) If any crack(s) is found that is equal to or exceeds a 
maximum depth of 0.5 mm on either side, prior to further flight, 
replace the cracked landing gear leg with a P/N 109B-5001.01/1 
landing gear leg, in accordance with the ``Actions'' section, 
paragraph B10, of Grob SB 817-39, dated January 4, 1994.
    (4) Replacing both landing gear legs with P/N 109B-5001.01/1 may 
be accomplished at any time as terminating action for the repetitive 
inspection requirement of this AD, but must be accomplished prior to 
further flight on any landing gear found cracked as specified in 
paragraph (b)(2) or (b)(3) of this AD.
    (5) If one landing gear leg is replaced prior to further flight 
when a crack is found, the other landing gear leg must still be 
repetitively inspected every 500 hours TIS until replacement with 
the improved design part.

    Note 2: Landing gear legs (P/N 109B-5001.01/1) have a ``0'' 
stamped on the front side of the leg for easy identification.

    (c) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the sailplane to a location where 
the requirements of this AD can be accomplished.
    (d) An alternative method of compliance or adjustment of the 
initial or repetitive compliance times that provides an equivalent 
level of safety may be approved by the Manager, Small Airplane 
Directorate, 1201 Walnut, suite 900, Kansas City, Missouri 64106. 
The request shall be forwarded through an appropriate FAA 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Small Airplane Directorate.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Small Airplane Directorate.

    (e) Questions or technical information related to Grob Service 
Bulletin TM 817-39, dated January 4, 1994, should be directed to 
Grob-Werke GmbH & Co. KG, Unternehmensbereich, Burkhart Grob 
Flugzeugbau, Flugplatz Mattsies, 86874 Tussenhausen, Germany. This 
service information may be examined at the FAA, Central Region, 
Office of the Regional Counsel, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.
    (f) The inspections, installation, polishing, and replacements 
required by this AD shall be done in accordance to Grob Service 
Bulletin TM 817-39, dated January 4, 1994. This incorporation by 
reference was approved by the Director of the Federal Register in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be 
obtained from Grob-Werke GmbH & Co. KG, Unternehmensbereich, 
Burkhart Grob Flugzeugbau, Flugplatz Mattsies, 86874 Tussenhausen, 
Germany. Copies may be inspected at the FAA, Central Region, Office 
of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, 
Missouri, or at the Office of the Federal Register, 800 North 
Capitol Street, NW, suite 700, Washington, DC.
    (g) This amendment becomes effective on January 9, 1999.
    Issued in Kansas City, Missouri, on November 16, 1998.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-31317 Filed 11-24-98; 8:45 am]
BILLING CODE 4910-13-U