AD 98-13-24 Airworthiness Directives; Bombardier Model CL-600-2B19 (Regional Jet Series 100) Airplanes

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.

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 a copy 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 [[Page 34576]] 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. Issued in Renton, Washington, on June 15, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 98-16448 Filed 6-24-98; 8:45 am] BILLING CODE 4910-13-U