Flex Coupling – April 5, 2017

We have previously recommended that the flex coupling connecting the main transmission output to
the tail rotor be replaced when showing signs of cracking.

As the photo below shows, the coupling can break before showing obvious signs. This coupling had
been on the helicopter for several years, but did not show signs of “spider cracks”. Considering the
low cost of the coupling and the ease of replacement, we recommend that you change the coupling
every two years.