AD 2020-23-01 Prompted By Reports Of Engine Power Fluctuations

The FAA is adopting a new airworthiness directive (AD) for all GE Aviation Czech s.r.o. (GEAC) M601D-11, M601E-11, M601E-11A, M601E-11AS, M601E-11S, M601F, H75-200, H80-100, H80-200, and H85-200 model turboprop engines.

This AD was prompted by reports of engine power fluctuations occurring during ground tests. This AD requires the removal and replacement of the fuel control unit (FCU). The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective November 24, 2020.

Supplementary Information: The European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA AD 2020-0201R1, dated September 25, 2020 (referred to after this as ¡§the MCAI¡¨), to address an unsafe condition for the specified products. The MCAI states:

• Several occurrences of engine power fluctuations have been reported during ground tests on engines equipped with an affected part. The investigation results determined that one or more rubber cuff sealings of the cage reinforcement inside the main metering valve of the FCU was wrongly installed, which reduced the cuff ability to properly seal the FCU working pressure.
• This condition, if not corrected, may lead to engine surge, fluctuations, or loss of engine power, possibly resulting in loss of control of control of the aeroplane.
• To address this potential unsafe condition, GEAC issued the ASB, providing replacement instructions, and EASA issued Emergency AD 2020-0201-E to require, for engines having an affected part installed, replacement with a serviceable part. That [EASA] AD also prohibited (re)installation of an affected part.
• Since that [EASA] AD was issued, it was discovered that an FCU s/n was incorrectly specified in the ASB and, consequently, wrongly quoted in the EASA AD. GEAC revised the ASB to correct that error and this [EASA] AD is revised to amend Appendix 1 (Group 3, s/n 903004 instead of 903008) accordingly.

You may obtain further information by examining the MCAI in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-0979.

FMI: www.regulations.gov