AD 2021-25-12 Requires Repetitive Lubrications Of The Trailing Arm Of The NLG

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. This AD is effective January 5, 2022.

Supplementary Information: The FAA issued AD 2017-19-09, Amendment 39-19039 (82 FR 43829, September 20, 2017) (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, -401, and -402 airplanes. AD 2017-19-09 was prompted by reports of discrepancies of a certain bolt at the pivot pin link, resulting in corrosion of the bolt. AD 2017-19-09 required modifying the NLG shock strut assembly. The FAA issued AD 2017-19-09 to address failure of the pivot pin retention bolt, which could result in a loss of directional control or loss of an NLG tire during takeoff or landing.

FMI: www.regulations.gov