AD 97-14-09

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Gulfstream Model G-159 (G-I) airplanes, that currently requires repetitive inspections to detect cracking in the mounting lugs of the elevator trim tab actuators, and replacement, if necessary. This amendment requires the installation of improved elevator trim tab actuators that are not susceptible to the subject cracking. This amendment is prompted by the development of a modification that positively addresses the identified unsafe condition. The actions specified by this AD are intended to prevent failure of the mounting lugs on the elevator trim tab actuator due to cracking; such failure could result in severe vibration during flight and/or reduction or loss of elevator trim tab capability, which could lead to reduced controllability of the airplane.

Final rule

97-14-09 GULFSTREAM AEROSPACE CORPORATION (previously Grumman): Amendment 39-10067. Docket 97-NM-15-AD. Supersedes AD 72-24-04, Amendment 39-1559.

Applicability: Model G-159 (G-I) airplanes, on which elevator trim tab actuators having part number 159SCC100-11 are not installed; certificated in any category.

NOTE 1: This AD applies to each airplane 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 airplanes 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 (e)(1) 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, unless accomplished previously.

To prevent failure of the elevator trim tab mounting lugs due to cracking, which could result in severe vibration during flight and a consequent reduction or loss of elevator trim tab capability, accomplish the following:

(a) Within 10 hours time-in-service after November 24, 1972 (the effective date of AD 72-24-04, amendment 39-1559), perform an inspection to detect cracks in the mounting lugs of the elevator trim tab actuators, having part number (P/N) 159SCC100-1 or -5; and shim to correct any out-of-plane condition, in accordance with Gulfstream Customer Bulletin No. 208A, dated November 18, 1971; Amendment 1, dated January 18, 1972; Amendment 2, dated April 21, 1972; and Gulfstream Operational Summary 72-5B, dated August 1972.

(b) If no crack is found in any mounting lug during the inspection required by paragraph (a) of this AD, repeat the inspection at intervals not to exceed 200 hours time-in-service.

(c) If any crack is found in a mounting lug when conducting any inspection required by paragraph (a) or (b) of this AD, prior to further flight, replace the elevator trim tab actuator with a new or serviceable actuator having P/N 159SCC100-1, -5, or -11.

(1) If an actuator having P/N 159SCC100-1 or -5 is used as the replacement unit, repeat the inspection for cracks specified in paragraph (a) of this AD thereafter at intervals not to exceed 200 hours time-in-service.

(2) If an actuator having P/N 159SCC100-11 is used as the replacement unit, no further inspection action is required for that unit in accordance with this AD.

(d) Within 1,000 hours time-in-service after the effective date of this AD, replace the elevator trim tab actuators with actuators that have P/N 159SCC100-11, in accordance with Gulfstream Aircraft Service Change No. 191, dated August 18, 1972. This installation constitutes terminating action for the inspections required by this AD.

(e) (1) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Atlanta ACO.

(2) Alternative methods of compliance, approved previously in accordance with AD 72-24-02, amendment 39-1559, are approved as alternative methods of compliance with this AD.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO.

(f) 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 airplane to a location where the requirements of this AD can be accomplished.

(g) The actions shall be done in accordance with Gulfstream Customer Bulletin No. 208A, dated November 18, 1971; Gulfstream Customer Bulletin No. 208A, Amendment 1, dated January 18, 1972; Gulfstream Customer Bulletin No. 208A, Amendment 2, dated April 21, 1972; Gulfstream Operational Summary 72-5B, dated August 1972; or Gulfstream Aircraft Service Change No. 191, dated August 18, 1972. 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 Gulfstream Aerospace Corporation, Technical Operations Department, P.O. Box 2206, M/S D-10, Savannah, Georgia 31402-2206. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Atlanta Aircraft Certification Office, Small Airplane Directorate, Campus Building, 1701 Columbia Avenue, Suite 2-160, College Park, Georgia; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(h) This amendment becomes effective on August 7, 1997.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 72-24-04, amendment 39-1559 (37 FR 24419, November 17, 1972), which is applicable to certain Gulfstream Model G-159 (G-I) airplanes, was published in the Federal Register on March 6, 1997 (62 FR 10231). The action proposed to continue to require repetitive dye penetrant inspections for cracks in the elevator trim tab actuator mounting lugs, and replacement, if necessary. It also proposed to require the installation of improved elevator trim tab actuators, which would constitute terminating action for the repetitive inspections.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact
There are approximately 146 Gulfstream Model G-159 airplanes of the affected design in the worldwide fleet. The FAA estimates that 72 airplanes of U.S. registry will be affected by this proposed AD.

The inspections that are currently required by AD 72-24-04 take approximately 2 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $8,640, or $120 per airplane, per inspection.

The new installation that is required by this AD action will take approximately 12 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will cost approximately $4,900 per airplane. Based on these figures, the cost impact of the required requirements of this AD on U.S. operators is estimated to be $404,640, or $5,620 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from 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.

39.13 - [Amended]
2. Section 39.13 is amended by removing amendment 39-1559 (37 FR 24419, November 17, 1972), and by adding a new airworthiness directive (AD), amendment 39-10067, to read as follows: