AD 98-11-18 ACTIVE

This amendment adopts a new airworthiness directive (AD) that applies to all Glaser-Dirks Flugzeugbau GmbH (Glaser-Dirks) Model DG-400 gliders. This AD requires replacing the upper rubber shock mounts with mounts made of stainless steel. This AD will also require inspecting the rear plate of the propeller mount for cracks and proper mounting, and replacing or modifying as necessary. 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 prevent failure of the propeller suspension system caused by cracks in the propeller mounts, which could result in loss of the propeller with consequent reduced glider controllability.

Final rule

98-11-18 GLASER-DIRKS FLUGZEUGBAU GMBH: Amendment 39-10543; Docket No. 98-CE-14-AD.
Applicability: Model DG-400 gliders, all serial numbers, certificated in any category.

NOTE 1: This AD applies to each glider 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 gliders 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 as indicated in the body of this AD, unless already accomplished.

To prevent failure of the propeller suspension system caused by cracks in the propeller mounts, which could result in loss of the propeller with consequent reduced glider controllability, accomplish the following:

(a) Within the next 3 calendar months after the effective date of this AD, replace the upper rubber shock mounts with mounts made of stainless steel in accordance with the Instructions section of Glaser-Dirks Technical Note TN 826/11, dated August 29, 1984.

(b) Within the next 3 calendar months after the effective date of this AD, inspect (using 2x or greater lens) the rear plate of the propeller mount for cracks and an excessive gap between the aluminum blocks and the plate (more than 1 mm or .04 inches). Accomplish these inspections in accordance with the Instructions section of Glaser-Dirks Technical Note TN 826/11, dated August 29, 1984.

(1) If any cracks are found in the propeller mount, prior to further flight, replace the propeller mount with an uncracked mount in accordance with the applicable maintenance manual.

(2) If an excessive gap exists between the aluminum blocks and the plate, prior to further flight, install washers in accordance with the Instructions section of Glaser-Dirks Technical Note TN 826/11, dated August 29, 1984.

(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 glider to a location where the requirements of this AD can be accomplished.

(d) An alternative method of compliance or adjustment of the compliance times that provides an equivalent level of safety may be approved by the Manager, Small Airplane Directorate, FAA, 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) Questions or technical information related to Glaser-Dirks Technical Note No. 826/11, dated August 29, 1984, should be directed to DG Flugzeugbau GmbH, Postfach 4120, D-76625 Bruchsal 4, Germany; telephone: +49 7257-89-0; facsimile: +49 7257-8922. 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 replacement, inspection, and installation required by this AD shall be done in accordance with Glaser-Dirks Technical Note No. 826/11, dated August 29, 1984. 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 DG Flugzeugbau GmbH, Postfach 4120, D-76625 Bruchsal 4, 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 is addressed in German AD 84-157, dated September 24, 1984.

(g) This amendment becomes effective on July 10, 1998.

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 all Glaser-Dirks Model DG-400 gliders was published in the Federal Register as a notice of proposed rulemaking (NPRM) on March 18, 1998 (63 FR 13151). The NPRM proposed to require the following:

- replacing the upper rubber shock mounts with mounts made of stainless steel;

- inspecting the rear plate of the propeller mount for cracks and an excessive gap between the aluminum blocks and the plate (more than 1 mm or .04 inches);

- replacing the rear plate of the propeller mount if cracks are found; and

- installing washers if an excessive gap exists between the aluminum blocks and the plate.

Accomplishment of the proposed shock mounts replacement, the proposed inspections, and the proposed installation, as specified in the NPRM would be in accordance with Glaser-Dirks Technical Note No. 826/11, dated August 29, 1984. Accomplishment of the proposed propeller mount replacement, as required, as specified in the NPRM, would be required in accordance with the applicable maintenance manual.

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.

Difference Between the Technical Note, German AD, and This AD
Both Glaser-Dirks Technical Note No. 826/11, dated August 29, 1984, and German AD 84-157, dated September 24, 1984, specify accomplishing the actions in this AD prior to further flight. The FAA does not have justification for requiring the action prior to further flight. Instead, the FAA has determined that 3 calendar months is a reasonable time period for accomplishing the actions in this AD.

Compliance Time of This AD
The compliance time of this AD is presented in calendar time instead of hours time-in-service (TIS) because of the typical usage of the affected gliders. For example, an operator of an affected glider may only utilize the glider 50 hours TIS in a year, while another operator may utilize an affected glider 50 hours TIS in one month. The FAA has determined that a compliance based on calendar time should be utilized in this AD in order to assure that the unsafe condition is addressed on all gliders in a reasonable time period.

Cost Impact
The FAA estimates that 35 gliders in the U.S. registry will be affected by this AD, that it will take approximately 6 workhours per glider to accomplish this action, and that the average labor rate is approximately $60 an hour. Parts cost approximately $100 per glider. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $16,100, or $460 per glider.

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 readas follows: Authority: 49 U.S.C. 106(g), 40113, 44701.

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

Service information that applies to this AD may be obtained from DG Flugzeugbau GmbH, Postfach 4120, D-76625 Bruchsal 4, Germany; telephone: +49 7257-89-0; facsimile: +49 7257-8922. This information may also be examined at the Federal Aviation Administration (FAA), Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 98-CE-14-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.

Mr. Mike Kiesov, Aerospace Engineer, Small Airplane Directorate, Aircraft Certification Service, FAA, 1201 Walnut, suite 900, Kansas City, Missouri 64106; telephone: (816) 426-6934; facsimile: (816) 426-2169.