The FAA has received reports indicating that, during recent inspections and operational tests of the elevator Hardover Prevention System (HOPS) on certain Gulfstream Model GV series airplanes, a configuration discrepancy was identified in which certain electrical connectors were incorrectly connected to the hydraulic deactivation valves of the elevator HOPS. The flight control hydraulic servos on the Gulfstream Model GV series airplane incorporate two redundant actuator pistons. The HOPS is designed to detect a runaway (or hardover) condition in either of these actuator pistons, and to subsequently shut down the affected side of the hydraulic servo. If the elevator HOPS is wired incorrectly, the system will shut down the wrong side of the hydraulic servo although that actuator is still operating properly. This condition, if not corrected, would prevent the correct operation of the elevator HOPS, which could result in loss of control of the airplane.Explanation of Relevant Service Information
The FAA has reviewed and approved Gulfstream Aerospace Alert Customer Bulletin No. 3, dated February 25, 1998, which describes procedures for performing a one-time inspection of the elevator HOPS to detect any incorrect wiring connections associated with the HOPS hydraulic deactivation valves, and corrective action, if necessary. The alert customer bulletin also describes procedures for a one-time functional test to ensure correct operation of the elevator HOPS.
In addition, the FAA has reviewed and approved Gulfstream Aerospace GV Customer Bulletin No. 4, dated March 31, 1998, which describes procedures for modifying the electrical harness of the hydraulic deactivation valves of the left elevator HOPS, and installing additional identification decals in order to prevent future miswiring. Accomplishment of the actions specified in this customer bulletin eliminates the need for the inspection and functional test specified in Gulfstream Alert Customer Bulletin No. 3.
Explanation of the Requirements of the Rule
Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design, this AD is being issued to prevent the incorrect operation of the elevator HOPS, which could result in loss of control of the airplane. This AD requires accomplishment of the actions specified in the customer bulletins described previously, except as discussed below.
Differences Between This Rule and Customer Bulletin
Operators should note that Gulfstream Aerospace Alert Customer Bulletin No. 3, dated February 25, 1998, describes a one-time inspection and functional test to verify proper electrical configuration and operation of the elevator HOPS. The FAA has determined that, because of the safety implications and consequences associated with energizing the incorrect hydraulic deactivation valve of the elevator HOPS, performance of the inspection and functional test is necessary following accomplishment of any maintenance action associated with the elevator HOPS, until the wiring modifications described in Gulfstream Aerospace GV Customer Bulletin No. 4, dated March 31, 1998, are accomplished.
Operators also should note that, although Gulfstream Aerospace Alert Customer Bulletin No. 3 specifies that the manufacturer may be contacted if technical assistance is required during accomplishment of the functional test, this AD requires that repair of any discrepancies be accomplished in accordance with a method approved by the FAA.
Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closingdate for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-NM-114-AD." The postcard will be date stamped and returned to the commenter.
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.
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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 FederalAviation 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 adding the following new airworthiness directive: