AD 2022-06-08 Retains The Actions Required By AD 2017-18-10

The FAA is superseding Airworthiness Directive (AD) 2017-18-10, which applied to certain Diamond Aircraft Industries GmbH (DAI) Model DA 42, DA 42 M-NG, and DA 42 NG airplanes.

AD 2017-18-10 required modifying the flap control system, repetitively inspecting the flap bell crank, and replacing the flap bell crank as necessary. Since the FAA issued AD 2017-18-10, the European Union Aviation Safety Agency (EASA) superseded its mandatory continuing airworthiness information (MCAI) to correct an unsafe condition on these products. This AD retains the actions required by AD 2017-18-10, expands the applicability, and prohibits the installation of certain flap bell cranks. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective May 9, 2022.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2017-18-10, Amendment 39-19019 (82 FR 42029, September 6, 2017) (AD 2017-1810). AD 2017-18-10 applied to certain serial-numbered DAI Model DA 42, DA 42 M-NG, and DA 42 NG airplanes. AD 2017-18-10 required modifying the flap control system by installing two spacers to replace a single long spacer, repetitively inspecting the flap bell crank, and replacing the flap bell crank with an improved part as necessary. The FAA issued AD 2017-18-10 to prevent failure of the flap bell crank, which could result in reduced control of the airplane.  The NPRM published in the Federal Register on December 23, 2021 (86 FR 72895). The NPRM was prompted by AD 2020-0008, dated January 20, 2020 (referred to after this as “the MCAI”), issued by EASA, which is the Technical Agent for the Member States of the European Union.

The MCAI states: 

• Occurrences were reported of finding cracks and deformation on certain flap bell cranks. Investigation results identified frequent high load conditions as the cause for these events. 
• This condition, if not detected and corrected, could lead to failure of the flap bell crank, possibly resulting in reduced control of the aeroplane. 
• To address this potential unsafe condition, DAI issued [Mandatory Service Bulletin] MSB 42-126/42NG-066 and the corresponding [Work Instructions] WI MSB 42126/42NG-066 (single document), providing inspection and modification instructions. Consequently, EASA issued AD 2017-0074 to require modification of the flap control system by installing two spacers to replace a single long spacer, repetitive inspections of the flap bell crank, and, depending on findings, replacement of the flap bell crank with an improved part. That [EASA] AD also provided an optional terminating action by installing an improved flap bell crank. 
• Since that [EASA] AD was issued, it was determined that early ‘Revisions' of P/N D60-2757-11-00 flap bell cranks are no longer acceptable and should be removed from service. Prompted by that determination, DAI issued the applicable MSB, as defined in this [EASA] AD, to provide the relevant instructions. 
• For the reason described above, this [EASA] AD retains the requirements of EASA AD 2017-0074, which is superseded, expands the applicability, and requires removal from service of certain affected parts.  

You may examine the MCAI in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-1077.

EASA made the determination to increase the applicability during a continued operational safety review. EASA determined that the earlier versions of the bellcranks could be installed on all serialnumbered airplanes and expanded the applicability accordingly.  In the NPRM, the FAA proposed to retain the actions of AD 2017-18-10 but expand the applicability and prohibit installing a flap bell crank with part number D60-2757-11-00, up to and including revision “d.”

FMI: www.regulations.gov