Airworthiness Directive · Amendment 39-21856 · Landing gear
De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes
Superseded. A later AD replaced this one: AD 2024-12-05. Comply with the one in force.
This AD applies to De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes, certificated in any category, serial numbers 4001 and 4003 and subsequent.
The FAA is superseding Airworthiness Directive (AD) 2017-19- 09, which applied to certain De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Model DHC-8-400 series airplanes. AD 2017-19-09 required modifying the nose landing gear (NLG) shock strut assembly. This new AD requires repetitive lubrications of the trailing arm of the NLG. This new AD also requires revising the existing maintenance or inspection program to include new and revised airworthiness limitations (life limits for certain bolts). This AD was prompted by reports of a certain bolt being found missing or having stress corrosion cracking. The FAA is issuing this AD to address the unsafe condition on these products.
For airplanes with pivot pin retention bolt part number (P/N) NAS6204-14D installed on the NLG assembly: Within 30 days after the effective date of this AD, or within 30 days after installation of pivot pin retention bolt part number P/N NAS6204-14D, whichever occurs later, revise the existing maintenance or inspection program, as applicable, to incorporate the information for Structures Safe Life Task 32-21-01-701 and Task 32-21-01-702, as specified in De Havilland Aircraft of Canada Limited Temporary Revision ALI-0223, dated October 15, 2020. The initial compliance time for doing the tasks is at the applicable time specified in De Havilland Aircraft of Canada Limited Temporary Revision ALI-0223, dated October 15, 2020, or within 30 days after the effective date of this AD, whichever occurs later; except, if replacement of bolt P/N NAS6204-14D was performed before the effective date of this AD as specified in De Havilland Aircraft of Canada Service Bulletin 84-32-161, the initial compliance time for Task 32-21-01-702 (bolt P/N NAS6204-14D replacement) is within 3 months after the effective date of this AD or within 800 flight cycles after performing the replacement, whichever occurs later.
After the existing maintenance or inspection program has been revised as required by paragraph (g) of this AD, no alternative actions (e.g., replacements) or intervals may be used unless the actions and intervals are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (j)(1) of this AD.
For airplanes with pivot pin retention bolt P/N NAS6204-14D installed on the NLG assembly: Within 30 days or 400 flight cycles, whichever occurs first after the effective date of this AD, and thereafter at intervals not exceeding 400 flight cycles, lubricate the trailing arm of the NLG, including doing a general visual inspection of the NLG pivot pin mechanism for discrepancies (i.e., bolt P/N NAS602-14D is missing or has damage (e.g., stress corrosion or stress corrosion cracking)) and, as applicable, replacing the bolt before further flight, in accordance with paragraph 3.B. of the Accomplishment Instructions of De Havilland Aircraft of Canada Limited Service Bulletin 84-32-167, dated August 12, 2021.
