AD 2014-05-28 Airworthiness Directives; Bombardier, Inc. Airplanes

Models named: DHC-8-400, -401, -402. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes, certificated in any category, serial numbers 4001 and subsequent, equipped with a main landing gear (MLG) up-lock having part number 46500-7 or 46500-9.

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 or inspection program, as applicable, to incorporate the information specified in Task Number 323100-202 of Bombardier Temporary Revision MRB-66, dated December 7, 2011, to Section 1-32, Systems/Powerplant Maintenance Program of MRB Report Part 1, Bombardier Q400 Dash 8 Maintenance Requirements Manual, PSM 1-84-7. The compliance time for the initial functional check is at the applicable time specified in paragraph (g)(1), (g)(2), or (g)(3) of this AD. The compliance time for the repetitive interval is at intervals not to exceed 6,000 flight hours or 60 months, whichever occurs first. Note 1 to Paragraph (g) of this AD: The maintenance or inspection program revision required by paragraph (g) of this AD may be done by inserting a copy of Bombardier Temporary Revision MRB-66, dated December 7, 2011, to Section 1-32, Systems/Powerplant Maintenance Program of MRB Report Part 1, Bombardier Q400 Dash 8 Maintenance Requirements Manual, PSM 1-84-7. When this temporary revision has been included in general revisions of the PSM, the general revisions may be inserted in the PSM, provided the relevant information in the general revision is identical to that in TR MRB-66. (1) For up-lock hook assemblies that have 15,000 total flight cycles or more as of the effective date of this AD: The compliance time for doing the initial functional check is within 600 flight cycles after the effective date of this AD. (2) For up-lock hook assemblies that have 12,000 total flight cycles or more, but fewer than 15,000 total flight cycles, as of the effective date of this AD: The compliance time for doing the initial functional check is within 1,200 flight cycles after the effective date of this AD, but before the accumulation of 15,600 total flight cycles on the assembly. (3) For up-lock hook assemblies with fewer than 12,000 total flight cycles as of the effective date of this AD: The compliance time for doing the initial functional check is within 6,000 flight cycles after the effective date of this AD, but before the accumulation of 13,200 total flight cycles on the assembly.

This AD was prompted by reports of excessive wear on the lower latch surface of the MLG up-lock hook. We are issuing this AD to detect and correct up-lock hooks worn beyond the wear limit, which could prevent the successful extension of the MLG using the primary landing gear extension system, which in combination with an alternate extension system failure could result in the inability to extend the MLG.

None.