Airworthiness directives: Learjet,

[Federal Register: December 29, 1999 (Volume 64, Number 249)]

[Proposed Rules]

[Page 72963-72964]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr29de99-33]

Proposed Rules Federal Register

This section of the FEDERAL REGISTER contains notices to the public of the proposed issuance of rules and regulations. The purpose of these notices is to give interested persons an opportunity to participate in the rule making prior to the adoption of the final rules.

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-311-AD]

RIN 2120-AA64

Airworthiness Directives; Learjet Model 35, 35A, 36, 36A, 55, 55B, and 55C Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM); rescission.

SUMMARY: This document proposes to rescind an existing airworthiness directive (AD), applicable to certain Learjet Model 35, 35A, 36, 36A, 55, 55B, and 55C airplanes. That AD currently requires installation of a placard on the instrument panel in the cockpit to advise the flightcrew that the Omega navigation system may be inoperative at certain engine speeds. That AD also provides for an optional installation of certain band reject filters, which eliminates the need for the placard. The actions specified by that AD are intended to prevent excessive deviation from the intended flight path due to loss of navigation signals, which could result in a potentially low-fuel condition or a traffic conflict. Since the issuance of that AD, use of the Omega navigation system has been permanently discontinued; therefore, the original unsafe condition no longer exists.

DATES: Comments must be received by February 14, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-311-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.

Information pertaining to this proposed rule may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Small Airplane Directorate, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas.

FOR FURTHER INFORMATION CONTACT: C. Dale Bleakney, Aerospace Engineer, Flight Test Branch, ACE-117W, FAA, Small Airplane Directorate, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid- Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4135; fax (316) 946-4407.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filedin the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 99-NM-311-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-311-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On September 5, 1995, the FAA issued AD 95-19-04, amendment 39-9365 (60 FR 47265, September 12, 1995), applicable to certain Learjet Model 35, 35A, 36, 36A, 55, 55B, and 55C airplanes. That AD requires installation of a placard on the instrument panel in the cockpit to advise the flightcrew that the Omega navigation system may be inoperative at certain engine speeds. That AD also provides for an optional installation of certain band reject filters, which eliminates the need for the placard. That action was prompted by reports of loss of certain navigation signals during extended over-water operation. The requirements of that AD are intended to prevent excessive deviation from the intended flight path due to loss of navigation signals, which could result in a potentially low-fuel condition or a traffic conflict.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, the FAA has received notification that use of the Omega navigation system has been permanently discontinued. Therefore, the FAA finds that the original unsafe condition (harmonic interference from the generator, which interferes with Omega navigation signals and could result in loss of navigation signals and, potentially, a low-fuel condition or a traffic conflict) no longer exists.

FAA's Conclusions

Since the unsafe condition no longer exists, the FAA has determined that it is necessary to rescind AD 95-19-04 in order to prevent operators from installing an unnecessary placard or unnecessary band reject filters. (Installation of certain band reject filters is provided in AD 95-19-04 as an optional alternative method of compliance with that AD.)

This proposed action would rescind AD 95-19-04. Rescission of AD 95-19-04 would constitute only such action, and, if followed by a final action, would not preclude the agency from issuing another notice in the future, nor would it commit the agency to any course of action in the future.

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Cost Impact

The FAA estimates that 177 airplanes of U.S. registry are affected by AD 95-19-04. The actions that are currently required by that AD take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. The cost of required parts (local manufacture of a placard) is negligible. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $10,620, or $60 per airplane. However, the adoption of this proposed rescission would eliminate those costs.

Should an operator elect to remove the placard required by AD 95- 19-04, it would take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of removal of the placard would be approximately $60 per airplane.

Should an operator elect to remove the band reject filters that were one option for compliance with AD 95-19-04, it would take approximately 15 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of removing the band reject filters would be approximately $900 per airplane.

Regulatory Impact

The regulations proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this proposed regulation (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) if promulgated, 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 draft regulatory 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, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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.

   Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing amendment 39-9365.

   Learjet: Docket 99-NM-311-AD. Rescinds AD 95-19-04, Amendment 39- 9365.

   Applicability: Model 35, 35A, 36, 36A, 55, 55B, and 55C airplanes; equipped with Global Wulfsburg GNS 500, GNS-1000, and GNS-X Flight Management Systems; certificated in any category.

   Issued in Renton, Washington, on December 22, 1999. D.L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 99-33734Filed12-28-99; 8:45 am]

   BILLING CODE 4910-13-U