Airworthiness Directives; Cessna Model 750 Citation X Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-229-AD]

RIN 2120-AA64

Airworthiness Directives; Cessna Model 750 Citation X Series

Airplanes

AGENCY: Federal Aviation Administration, DOT.

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

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SUMMARY: This document proposes to rescind an existing airworthiness

directive (AD), applicable to all Cessna Model 750 Citation X series

airplanes, that currently requires repetitive in-flight functional

tests to verify proper operation of the secondary horizontal stabilizer

pitch trim system, and repair, if necessary. The actions specified by

that AD are intended to detect and correct such contamination and

damage, which could result in simultaneous failure of both primary and

secondary pitch trim systems, and consequent reduced controllability of

the airplane. Since the issuance of that AD, an improved part has been

developed, which, if installed, would terminate the repetitive tests;

that improved part has been installed on all affected airplanes or is

being installed in production. Therefore, the identified unsafe

condition no longer exists.

DATES: Comments must be received by February 22, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-114,

Attention: Rules Docket No. 99-NM-229-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.

ane Directorate, ANM-114,

Attention: Rules Docket No. 99-NM-229-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.

FOR FURTHER INFORMATION CONTACT: Joel M. Ligon, Aerospace Engineer,

Systems and Propulsion Branch, ACE-116W, FAA, Small Airplane

Directorate, Wichita Aircraft Certification Office, 1801 Airport Road,

Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316)

946-4138; 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 filed in 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-229-AD.'' The postcard will be date stamped and

returned to the commenter.

Availability of NPRMs

tch trim system during flight, due to internal

water contamination and corrosion damage in the system actuator. The

requirements of that AD are intended to detect and correct such

contamination and damage, which could result in simultaneous failure of

both primary and secondary pitch trim systems, and consequent reduced

controllability of the airplane.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, the manufacturer has developed a

modification (reference Cessna Service Bulletin SB750-27-23, dated

February 2, 1999) that involves replacement of the horizontal

stabilizer trim system actuator with an improved actuator incorporating

a moisture condenser. The improved design will prevent internal water

contamination and corrosion damage of the actuator. The FAA has

determined that installation of this improved actuator will adequately

address the unsafe condition identified in AD 98-16-17, and will

eliminate the need for the repetitive in-flight functional tests

required by that AD.

The manufacturer has verified that the modification has been

accomplished on all affected airplanes, including those in production,

and on all actuators in operators' inventories. Therefore, the unsafe

condition cannot be reintroduced into the fleet.

FAA's Conclusions

Since all affected airplanes, including those in production, and

all actuators in operators' inventories have been modified, the FAA has

determined that it is necessary to rescind AD 98-16-17 in order to

prevent operators from performing an unnecessary action.

This proposed action would rescind AD 98-16-17. Rescission of AD

98-16-17 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.

Cost Impact

The FAA estimates that 52 airplanes of U.S. registry are affected

by AD 98-

cessary action.

This proposed action would rescind AD 98-16-17. Rescission of AD

98-16-17 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.

Cost Impact

The FAA estimates that 52 airplanes of U.S. registry are affected

by AD 98-

16-17. The actions that are currently required by that AD 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 $6,240, or $120 per airplane. However, the adoption of this

proposed rescission would eliminate those costs.

Regulatory Impact

The regulations proposed herein would 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. Therefore, it

is determined that this proposal would not have federalism implications

under Executive Order 13132.

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

tities 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 39-10693.

Cessna Aircraft Company: Docket 99-NM-229-AD. Rescinds AD 98-16-17,

Amendment 39-10693.

Applicability: All Model 750 Citation X series airplanes,

certificated in any category.

Issued in Renton, Washington, on January 3, 2000.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 00-377 Filed 1-6-00; 8:45 am]

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