Quality of Swtiches used for Engine Power
Be careful with the quality of the switches used for the engine power circuits. In an experimental airplane assembled in another country, with a Rotax 912iS engine, an intermittent failure appeared. The red Lane B and Lane A lights when starting the engine sometimes flashed, other times they stayed completely red, having to go back to the starting procedure. Other times in flight, Lane A or B's voltage ranged between quite different values. After investigating the problem, we found that the fault was in the quality of the toggle switches that had been installed. They were of such poor quality that did not support the Amps specified in Rotax installation manual. It is also important to copy the starting procedure recommended by Rotax in the Checklist, where both Lanes must always be turned on BEFORE giving Start Power. I attach some photographs of the switch and the internal contacts that were quite damaged, as well as a rivet that goes to the loose connection screw. When choosing a switch, we always take into account its Quality and the Amps it supports. We replaced al swtiches with MS35058 or MS35059 aviation grade swtiches. This is very critical in the LANES, Fuel Pump, Master and Start Power switches. And this is valid for other engines such as 915 and 916 also.
