AD 2021-25-10 Requires Modifying The Oil Cooler Air Induction Duct

The FAA is adopting a new airworthiness directive (AD) for certain Daher Aerospace (type certificate previously held by SOCATA) (Daher) Model TBM 700 airplanes.

This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The unsafe condition that is the subject of the MCAI is ice accumulation on the oil cooler air inlet duct fin. This AD requires modifying the oil cooler air induction duct. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective January 24, 2022.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to Daher Model TBM 700 airplanes with certain oil cooler air induction ducts installed. The NPRM published in the Federal Register on August 18, 2021 (86 FR 46160). The NPRM was based on MCAI from the European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union. EASA issued AD 2018-0133, dated June 22, 2018, and corrected June 25, 2018 (referred to after this as “the MCAI”), to address the unsafe condition on certain Daher Model TBM 700 airplanes.

The MCAI states:

• During flight testing in icing conditions, oil temperature increase was observed.
• Subsequent investigation determined that the loss of efficiency of the oil cooler system was due to ice accumulation on the engine air induction duct fins.
• This condition, if not corrected, could lead to uncommanded engine in-flight shutdown and reduced control of the aeroplane.
• To address this potential unsafe condition, DAHER AEROSPACE developed MOD 70-0616-79 for aeroplanes in production, removing the 4 upper fins of the oil cooler air induction duct to avoid ice accumulation, available for in-service aeroplanes through the SB [Daher Aerospace Service Bulletin 70-254, dated April 18, 2018].
• For the reasons described above, this [EASA] AD requires modification of the oil cooler air induction duct.

You may examine the MCAI in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-1069.

Although the unsafe condition statement in the MCAI identifies the cause as ice accumulation on the engine air induction fin, the FAA has determined that this does not accurately identify the affected air path. The affected area is the oil cooler air inlet duct fin.

In the NPRM, the FAA proposed to require modifying the oil cooler air induction duct. The FAA is issuing this AD to prevent ice from accumulating on the oil cooler air induction duct fins, which could lead to an increase in oil temperature, uncommanded engine inflight shutdown, and reduced airplane control.

FMI: www.regulations.gov