04-24522. Airworthiness Directives; GROB-WERKE Model G120A Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

The FAA adopts a new airworthiness directive (AD) for all GROB-WERKE (GROB) Model G120A airplanes. This AD requires you to repetitively inspect visually the area between the vertical stabilizer main spar and the nearby vertical stabilizer skin for any disbonding/crack; repair any disbonding/crack found; and calculate weight and balance after any repair. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Germany. We are issuing this AD to detect and correct any disbonding/crack in the area between the vertical stabilizer main spar and nearby stabilizer skin, which could result in possible structural failure. This failure could lead to difficulty in airplane flight control.

DATES:

This AD becomes effective on December 27, 2004.

As of December 27, 2004, the Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulation.

ADDRESSES:

To get the service information identified in this AD, contact GROB Luft-und Raumfahrt, Lettenbachstrasse 9, D-86874 Tussenhausen-Mattsies, Federal Republic of Germany; telephone: [phone]; facsimile: 011 49 8268 998200. To review this service information, go to the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html or call [phone].

To view the AD docket, go to the Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-001 or on the Internet at http://dms.dot.gov. The docket number is FAA-2004-18030.

FOR FURTHER INFORMATION CONTACT:

Karl Schletzbaum, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; facsimile: [phone].

SUPPLEMENTARY INFORMATION:

 

Discussion

What events have caused this AD? The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority for Germany, recently notified FAA that an unsafe condition may exist on all GROB Model G120A airplanes. The LBA reports that a routine inspection of a Model G120A-I airplane found disbonding/cracking in the area between the vertical stabilizer main spar and nearby vertical stabilizer skin near the VOR (very high frequency omni directional range) antenna. A fleet-wide inspection of the Model G120A-I airplane fleet found one other Model G120A-I airplane with disbonding/cracking in the same area. The most likely reason for the disbonding/cracking was an incorrectly installed antenna support bracket, which caused permanent tension on the bonding seam. This resulted in disbonding/cracking in the area near the VOR antenna.

What is the potential impact if FAA took no action? Any disbonding/crack in the area between the vertical stabilizer main spar and nearby stabilizer skin could result in possible structural failure. This failure could lead to difficulty in airplane flight control.

Has FAA taken any action to this point? We issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to all GROB Model G120A airplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on July 15, 2004 (69 FR 42360). The NPRM proposed to require you to repetitively inspect visually the area between the vertical stabilizer main spar and the nearby vertical stabilizer skin for any disbonding/crack; repair any disbonding/crack found; and calculate weight and balance after any repair.

Comments

Was the public invited to comment? We provided the public the opportunity to participate in developing this AD. We received no comments on the proposal or on the determination of the cost to the public.

Conclusion

What is FAA's final determination on this issue? We have carefully reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed except for minor editorial corrections. We have determined that these minor corrections:

—Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and

—Do not add any additional burden upon the public than was already proposed in the NPRM.

Changes to 14 CFR Part 39—Effect on the AD

How does the revision to 14 CFR part 39 affect this AD? On July 10, 2002, the FAA published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.

Costs of Compliance

How many airplanes does this AD impact? We estimate that this AD affects 6 airplanes in the U.S. registry.

What is the cost impact of this AD on owners/operators of the affected airplanes? We estimate the following costs to do the inspection:

Labor cost	Parts cost	Total cost per airplane	Total cost on U.S. operators
1 workhour × $65 per hour = $65	Not applicable	$65	6 × $65 = $390

We estimate the following costs to do any necessary repairs that would be required based on the results of this proposed inspection. We have no way of determining the number of airplanes that may need this repair:

Labor cost	Parts cost	Total cost per airplane
20 workhours × $65 per hour = $1,300	The manufacturer covers under warranty and will supply any parts for the new U-profile assembly (antenna support bracket) consisting of part numbers: 120A-2363.02; 120A-2364; and 120A-2365	$1,300

Regulatory Findings

Will this AD impact various entities? We have 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.

Will this AD involve a significant rule or regulatory action? For the reasons discussed above, I certify that this AD:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the 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 summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “Docket No. FAA-2004-18030; Directorate Identifier 2004-CE-13-AD” in your request.

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 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.

§ 39.13

[Amended]

2. FAA amends § 39.13 by adding a new AD to read as follows:

2004-22-21 Grob-Werke: Amendment 39-13849; Docket No. FAA-2004-18030; Directorate Identifier 2004-CE-13-AD.

When Does This AD Become Effective?

(a) This AD becomes effective on December 27, 2004.

What Other ADs Are Affected by This Action?

(b) None.

What Airplanes Are Affected by This AD?

(c) This AD affects Model G120A airplanes, all serial numbers, that are certificated in any category.

What Is the Unsafe Condition Presented in This AD?

(d) This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Germany. The actions specified in this AD are intended to detect and correct any disbonding/crack in the area between the vertical stabilizer main spar and nearby stabilizer skin, which could result in possible structural failure. This failure could lead to difficulty in airplane flight control.

What Must I Do To Address This Problem?

(e) To address this problem, you must do the following:

Actions	Compliance	Procedures
(1) Inspect the area between the vertical stabilizer main spar and the nearby vertical stabilizer skin for any disbonding/crack along the spar/skin contact (both sides of the vertical stabilizer)	Within the next 50 hours time-in-service (TIS) after December 27, 2004 (the effective date of this AD), unless already done. Repetitively inspect thereafter at every 50 hours TIS	Follow GROB Luft-und Raumfahrt Service Bulletin No. MSB 1121-049, dated April 20, 2004. The applicable airplane maintenance manual also addresses this issue.
(2) If any disbonding/crack is found during any inspection required by paragraph (e)(1) of this AD: (i) Get a repair instruction from the manufacturer; and (ii) Follow this repair instruction. (iii) The repetitive inspections of paragraph (e)(1) of this AD are still required after any repair.	Before further flight after any inspection required by paragraph (e)(1) of this AD where any disbonding/crack is found	Follow GROB Luft-und Raumfahrt Service Bulletin No. MSB1121-049, dated April 20, 2004; and any repair instruction obtained from GROB Luft-und Raumfahrt, Lettenbachstrasse 9, D-86874 Tussenhausen-Mattsies, Federal Republic of Germany; telephone: [phone]; facsimile: 011 49 8268 998200. Obtain approval of this repair instruction through the FAA at the address specified in paragraph (f) of this AD. The applicable airplane maintenance manual also addresses this issue.
(3) Calculate weight and balance after any repair required by paragraph (e)(2) of this AD	Before further flight after any repair required by paragraph (e0(2) of this AD	Follow GROB Luft-und Raumfahrt Service Bulletin No. MSB1121-049, dated April 20, 2004. The applicable airplane maintenance manual also addresses this issue.

May I Request an Alternative Method of Compliance?

(f) You may request a different method of compliance or a different compliance time for this AD by following the procedures in 14 CFR 39.19. Unless FAA authorizes otherwise, send your request to your principal inspector. The principal inspector may add comments and will send your request to the Manager, Standards Office, Small Airplane Directorate, FAA. For information on any already approved alternative methods of compliance, contact Karl Schletzbaum, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; facsimile: [phone].

Is There Other Information That Relates to This Subject?

(g) German AD Number D-2004-204, dated April 23, 2004, also addresses the subject of this AD.

Does This AD Incorporate Any Material by Reference?

(h) You must do the actions required by this AD following the instructions in GROB Luft-und Raumfahrt Service Bulletin No. MSB1121-049, dated April 20, 2004. The Director of the Federal Register approved the incorporation by reference of this service bulletin in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. To get a copy of this service information, contact GROB Luft-und Raumfahrt, Lettenbachstrasse 9, D-86874 Tussenhausen-Mattsies, Federal Republic of Germany; telephone: [phone]; facsimile: 011 49 8268 998200. To review copies of this service information, go to the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html or call [phone]. To view the AD docket, go to the Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-001 or on the Internet at http://dms.dot.gov. The docket number is FAA-2004-18030.

Issued in Kansas City, Missouri, on October 27, 2004.

David R. Showers,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.