EC 120 EAD
 

2 December 2015

CAA have adopted FAA notice. For machines fitted with Air Comm system. One machine had a TR drive fail, on inspection another had significant wear. Flight prohibited until inspected, 25 hr thereafter for inspection, or replace the drive wheel with Airbus unit.

Fly safe


FAA EAD 2015-24

Hi john,

Do you mean air conditioning ??

Thanks

Yes, specifically the Air Comm kit (STC SR00491DE). There is a drive wheel for the AC compressor which is inserted into the drive shaft to the tail rotor. Splined mating face so that power is taken for the AC compressors and the TR continues to turn.


It seems that there can be movement leading to wear, which strips the splines and eventually there is no friction and this stops drive to the TR.


Only on this model, one fix is to remove the AC drive wheel and replace with an Airbus unit. Check the CAA web page. New link below as that last one does not appear to connect.


http://www.caa.co.uk/docs/33/20151127FAAAD20152451.pdf

I have a few machines with the Aircomm aircon but only one affected as the aircon was recently installed. It seems like Aircomm changed the drive flange from being a seperate splined drive infront of the rotorbrake disc driving the belt to a integrated unit which is now behind the rotorbrake disc and is the flange driving the Tail Driveshaft as well. Why did they change? Surely they can go back to the original STC fit which will solve this immediately?

We will be disabling the compressor and replacing the Aircomm unit with the Airbus flange as 25hrs is 4-5 days flying ap the AD./

Lucky me, no air con installed, not affected :ok:

Unlucky you, no aircon... flying a plastic greenhouse in the summer, and in the winter harder to clear moisture. My 44 and first 120 didn't have aircon but now I would not go back.