AD 98-13-24

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100) airplanes, that currently requires a revision to the Airplane Flight Manual (AFM) to prohibit the use of mach trim and to add speed restrictions if the autopilot is disengaged or inoperative. That AD also requires installation of an associated placard. This amendment adds requirements for replacement of the horizontal stabilizer trim control unit (HSTCU) with a new HSTCU, and reactivation of the mach trim engage/disengage switch/light (if deactivated). Accomplishment of these actions terminates the requirements of the existing AD. This amendment also limits the applicability of the existing AD. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent deficiencies of the HSTCU, which could result in a nose-up trim runaway when a single component in the mach trim circuit fails.

Final rule.

98-13-24 BOMBARDIER, INC. (Formerly Canadair): Amendment 39-10615. Docket 97-NM-83-AD. Supersedes AD 95-13-04, Amendment 39-9325.

Applicability: Model CL-600-2B19 (Regional Jet Series 100) airplanes, serial numbers 7003 through 7112 inclusive; 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 (d)(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 deficiencies of the horizontal stabilizer trim control unit (HSTCU), which could result in a nose-up trim runaway when a single component in the mach trim circuit fails, accomplish the following:

RESTATEMENT OF REQUIREMENTS OF AD 95-13-04:

(a) Within 24 hours after August 14, 1995 (the effective date of AD 95-13-04, amendment 39-9325), accomplish the requirements of paragraphs (a)(1), (a)(2), and (a)(3) of this AD.

(1) Install a placard adjacent to the primary flight display next to the airspeed limitation placard, to read:

"USE OF MACH TRIM IS PROHIBITED. IF THE
AUTOPILOT IS DISENGAGED OR INOPERATIVE,
RESTRICT SPEED TO 250 KIAS OR 0.7 MACH."

(2) Revise the Limitations section of the FAA-approved Airplane Flight Manual (AFM) to include the following information. The requirements of this paragraph may be accomplished by inserting acopy of this AD, or Canadair Regional Jet Temporary Revision No. TR RJ/43, into the AFM.

"USE OF MACH TRIM IS PROHIBITED. IF THE
AUTOPILOT IS DISENGAGED OR INOPERATIVE,
RESTRICT SPEED TO 250 KIAS OR 0.7 MACH."

NOTE 2: When the temporary revision has been incorporated in the general revisions of the AFM, the general revisions may be inserted in the AFM, provided the information contained in the general revision is identical to that specified in Canadair Regional Jet Temporary Revision No. TR RJ/43.

(3) Revise the Limitations section of the FAA-approved AFM to include the following information. The requirements of this paragraph may be accomplished by inserting a copy of this AD into the AFM.

"Prior to the accomplishment of Bombardier Alert Service Bulletin S.B. A601R-27-054, dated June 12, 1995, when the Mach trim system is disengaged, the "MACH TRIM" caution message will be displayed on the Engine Indication and Crew Alerting System (EICAS), and the Mach trim engage/disengage switch "INOP" legend will be illuminated. The EICAS message may be scrolled out of view prior to takeoff, but the switch "INOP" light will remain illuminated."

NEW REQUIREMENTS OF THIS AD:
(b) Within 18 months after the effective date of this AD, replace the HSTCU with a new HSTCU having part number 601R92301-9, and reactivate the mach trim switch/light (if deactivated), in accordance with Bombardier Service Bulletin S.B. 601R-27-053, Revision B, dated February 21, 1997. Accomplishment of this modification constitutes terminating action for the requirements of paragraph (a) of this AD; after the modification has been accomplished, the previously required AFM limitation may be removed.

NOTE 3: Accomplishment of paragraph (b) of this AD, prior to the effective date of this AD, in accordance with Bombardier Service Bulletin S.B. 601R-27-053, dated May 27, 1996; or Revision A, dated August 26, 1996; is considered acceptable for compliance with the applicable actions specified in this amendment.

(c) As of the effective date of this AD, no person shall install on any airplane any HSTCU having part number 601R92301-5, 601R92301-7, or 601R92301-951.

(d) (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, New York Aircraft Certification Office (ACO), FAA, Engine and Propeller Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.

(d) (2) Alternative methods of compliance approved previously in accordance with AD 95-13-04, amendment 39-9325, are approved as alternative methods of compliance with this AD.

NOTE 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

(e) 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.

(f) The actions shall be done in accordance with Bombardier Service Bulletin S.B. 601R-27-053, Revision B, dated February 21, 1997. 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 Bombardier, Inc., Canadair Aerospace Group, P.O. Box 6087, Station Centre-ville, Quebec H3C 3G9, Canada. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Engine and Propeller Directorate, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 5:The subject of this AD is addressed in Canadian airworthiness directive CF-95-08R2, dated July 23, 1996.

(g) This amendment becomes effective on July 30, 1998.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 95-13-04, amendment 39-9325 (60 FR 38668, July 28, 1995), which is applicable to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100) airplanes, was published in the Federal Register on April 14, 1998 (63 FR 18160). The action proposed to continue to require a revision to the AFM to prohibit the use of mach trim and to add speed restrictions if the autopilot is disengaged or inoperative, and to require installation of an associated placard. The action proposed to add requirements for replacement of the horizontal stabilizer trim control unit (HSTCU) with a new HSTCU, and reactivation of the mach trim engage/disengage switch/light (if deactivated). Accomplishment of these actions would terminate the requirements of the existing AD. That AD also proposed to limit the applicability of the existing AD.

Comments

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.

Corrections to the Proposal

In paragraph (b) of the proposed rule, the FAA inadvertently referenced Bombardier Service Bulletin S.B. 601R-27-053, dated May 27, 1996; and Revision A, dated August 26, 1996; for accomplishment of the proposed actions. Paragraph (b) of this final rule has been revised to reference only Bombardier Service Bulletin S.B. 601R-27-053, Revision B, dated February 21, 1997. In addition, NOTE 3 has been added to reference the original issue and Revision A of the service bulletin as acceptable means of compliance for operators that have accomplished the applicable actions prior to the issuance of this AD.

The FAA has become aware of a typographical error that appeared in paragraph (d)(2) of the proposal. The AD number referenced in that paragraph appeared incorrectly as AD93-13-04. Paragraph (d)(2) of this final rule has been revised to correctly specify that AD number as AD 95-13-04.

Conclusion

The FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact

There are approximately 54 Bombardier Model CL-600-2B19 (Regional Jet Series 100) airplanes of U.S. registry that will be affected by this AD.

The actions that are currently required by AD 95-13-04, and retained in this 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 $6,480, or $120 per airplane.

The new actions that are required by this new AD will take approximately 3 work hours perairplane to accomplish, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the new requirements of this AD on U.S. operators is estimated to be $9,720, or $180 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 FederalismAssessment.

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 39-9325 (60 FR 38668, July 28, 1995), and by adding a new airworthiness directive (AD), amendment 39-10615, to read as follows: