My Factory built taildragger is fitted with a Rotax 912ULS engine & over the years of my ownership I've had intermittent low fuel pressure indication in flight, always perfect on the ground. The engine has always performed faultlessly even during the periods of low fuel pressure indication. This is a well documented issue on various forums including Rotax-owner.com and I've tried most of the remedies to no avail. Last week I stumbled upon "Technical Advisory 120414" by Dynon Avionics issued in December 2014. Although my aircraft is fitted with Garmin avionics, it uses Kavlico pressure senders as supplied by Garmin. As the symptoms described in the advisory closely match those I have experienced, I followed the instruction to remove the gasket/seal and perform a test flight. Gladly this was successful with the pressure indication stable through all phases of flight. This sender has the ambient pressure sense port inside the electrical connector and the gasket prevents pressure equalisation as the aircraft climbs or descends giving the false pressure indication. I have a later version of the sensor with an external ambient sense port supplied with my kit avionics that I will not be using so I'll install that in the factory built aircraft later this year when the 5 year rubber exchange is performed.
