AD 97-24-10

This amendment adopts a new airworthiness directive (AD) that applies to Burkhart Grob Luft-und Raumfahrt, GmbH. (Grob) Model G 103 Twin Astir sailplanes. This action requires replacing the airbrake over-center lever and installing new inspection holes. The AD is the result of cracked airbrake over-center levers found during routine inspections. The actions specified by this AD are intended to prevent an asymmetrical airbrake deployment, which could result in an uncontrollable roll and possible loss of control of the sailplane.

Final rule

97-24-10 BURKHART GROB LUFT-UND RAUMFAHRT, GMBH: Amendment 39-10217; Docket No. 95-CE-96-AD.

Applicability: Model G 103 Twin Astir Sailplanes, (serial numbers 3000 through 3291, with or without the suffix "T"), 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.

Compliance: Required within the next 50 hours time-in-service (TIS) after the effective date of this AD, unless already accomplished.

To prevent an asymmetrical airbrake deployment, which could result in an uncontrollable roll and possible loss of control of the sailplane, accomplish the following:

(a) Replace the airbrake over-center lever (Grob part number (P/N) 103-4123 (left) and 103-4124 (right), or FAA-approved equivalent part numbers) with a new part of improved design (Grob P/N 103B-4123 (left), and 103B-4124 (right), or FAA-approved equivalent part numbers) in accordance with the Procedures section of Grob Service Bulletin (SB) TM 315-47/2, dated January 20, 1993, and Grob Repair Instructions No. 315-45/2, dated October 11, 1991. Use the dimension called out in the materials list on page one of the Repair Instructions for the correct dimension of the composite sheet.

(b) Install inspection holes in accordance with the Procedure section of Grob Repair Instructions No.315-45/2, dated October 11, 1991.

(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 compliance time 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 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Small Airplane Directorate.

(e) The modification and replacement required by this AD shall be done in accordance with Burkhart Grob Luft-und Raumfahrt, GmbH G 103 Service Bulletin TM 315- 47/2, dated January 20, 1993, and Burkhart Grob Luft-und Raumfahrt, GmbH Repair Instructions No. 315-45/2, dated October 11, 1991. 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 also be obtained from Grob Luft-und Raumfahrt, GmbH., D-8939, Mattsies-am Flugplatz, 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.

NOTE 3: The subject of this AD addresses German AD 92-309/2 Grob, dated February 26, 1993.

(f) This amendment (39-10217) becomes effective on December 29, 1997.

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 Grob Model G 103 Twin Astir sailplanes was published in the Federal Register on December 23, 1996 (61 FR 67506). The action proposed to require replacing the airbrake over-center lever (Grob part number (P/N) 103-4123 (left) and P/N 103-4124 (right)) with a new part of improved design, (Grob P/N 103B-4123 (left) and 103B-4124 (right), or FAA-approved equivalent part numbers) and installing new inspection holes.

Accomplishment of the proposed action would be in accordance with Grob Service Bulletin TM 315-47/2, dated January 20, 1993, and Grob Repair Instructions No. 315-45/2, dated October 11, 1991.

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.

After examining all information related to this AD, the FAA has noticed two discrepancies in the NPRM that should be clarified in the final rule.

First, clarification is required regarding Grob Repair Instructions TM 315-45/2. There is a difference between the dimensions called out in Drawing 3 of Grob Repair Instructions TM 315-45/2 and the dimensions called out in the materials list on page one of the Repair Instructions for the composite sheet used for the 2 composite stops. Specifically, refer to the material list on page one of the repair instructions, which calls out 2 stops of 3mm x 30mm x 30mm composite sheet. Drawing 3 calls out the composite sheet material as 3mm x 30mm x 40mm, but should actually call out the composite sheet material as 3 x 30 x 30. The material list on page one is the correct dimension.

Secondly, there are only 18 Grob Model G 103 sailplanes in the U.S. registry rather than the figure of 60 sailplanes that was originally published in the NPRM. This would lower the cost impact on the U.S. operators, and would not have an adverse impact.

The FAA's Determination
After careful review of all available information related to the subject presented above, including the service information, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for the addition of a note to refer to the materials list for correct dimensions on the composite sheet, the lowering of the number of sailplanes affected, and minor editorial corrections. The FAA has determined that these 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 18 sailplanes in the U.S. registry will be affected by this AD, that it will take approximately 12 workhours per sailplane to accomplish the action, and that the average labor rate is approximately $60 an hour. Parts cost approximately $650 per sailplane. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $24,660 or $1,370 per sailplane.

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 USC 106(g), 40113, 44701.

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