AD 2012-06-03 Airworthiness Directives; Bombardier, Inc. Model BD-100-1A10 (Challenger 300) Airplanes

(1) This AD applies to all Bombardier, Inc. Model BD-100-1A10 (Challenger 300) airplanes, certificated in any category. (2) This AD requires revisions to certain operator maintenance documents to include new inspections. Compliance with these tasks is required by 14 CFR 91.403(c). For airplanes that have been previously modified, altered, or repaired in the areas addressed by these inspections, the operator may not be able to accomplish the inspections described in the revisions. In this situation, to comply with 14 CFR 91.403(c), the operator must request approval for an alternative method of compliance according to paragraph (j) of this AD. The request should include a description of changes to the required inspections that will ensure the continued operational safety of the airplane.

You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Within 30 days after the effective date of this AD: Revise the maintenance program by incorporating Task 27-40-00-107, “Functional Test of the Horizontal Stabilizer Trim Actuator (HSTA) No Back,” in accordance with Bombardier Temporary Revision 5-2-59, dated November 25, 2010, to Section 5-10-40, of Part 2, of the Bombardier Challenger 300 BD-100 Time Limits/Maintenance Checks Manual. For this task, the initial compliance time starts at the applicable time specified in paragraph (g)(1) or (g)(2) of this AD. Note 1 to paragraphs (g) and (h) of this AD: The maintenance program revision required by paragraphs (g) and (h) of this AD may be done by inserting a copy of Bombardier Temporary Revision 5-2-59, dated November 25, 2010, into Section 5-10-40, of Part 2, of the Bombardier Challenger 300 BD-100 Time Limits/Maintenance Checks Manual. When this Temporary Revision has been included in the general revisions of Section 5-10-40, of Part 2, of the Bombardier Challenger 300 BD-100 Time Limits/Maintenance Checks Manual, the general revisions may be inserted in Section 5-10-40, of Part 2, of the Bombardier Challenger 300 BD-100 Time Limits/Maintenance Checks Manual, provided that the relevant information in the general revision is identical to that in Bombardier Temporary Revision 5-2-59, dated November 25, 2010, to Section 5-10-40, of Part 2, of the Bombardier Challenger 300 BD-100 Time Limits/Maintenance Checks Manual. (1) For HSTAs with 2,600 or fewer total flight hours on the HSTA as of the effective date of this AD: Prior to the accumulation of 3,000 total flight hours on the HSTA. (2) For HSTAs with more than 2,600 total flight hours on the HSTA as of the effective date of this AD: Within 400 flight hours or 6 months after the effective date of this AD, whichever occurs first.

This AD was prompted by reports that the horizontal stabilizer trim actuator (HSTA) no-back and the number 1 motor brake assembly (MBA) can both fail dormant. We are issuing this AD to prevent dormant failure of the HSTA no-back and the number 1 MBA, which along with additional component failure could result in an uncontrollable horizontal stabilizer surface runaway without the ability to retrim, and consequent loss of the airplane.

None.