[Orv Neisingh]

The two 30 amp fuses that protect the two circuits from the alternator have a problem. One fuse protects the wire that goes to the battery for charging and the other fuse protects the wire that goes to the overhead panel from the alternator. A proper pre-flight inspection would have the pilot remove the rubber cap over the fuse every time to check to see if one of the fuses has blown. If one fuse is blown the system will still work because all of the engine systems are fed from both the battery and the alternator in the standard Rotorway wiring configuration. 

How many of you actually remove the rubber cap and inspect those fuses on every pre-flight? I know that I did not. If one of the fuses has blown then we are flying with only half of the electrical system powering the overhead. If the other fuse should then blow it will shut off all alternator power to the overhead panel. 

A simple solution is to install reset able breakers to replace the fuses. If the breaker trips a red flag drops down and is easily seen during your preflight inspection. With a standard battery installed it would require two 30 amp breakers to replace the fuses. If Lithium batteries are installed then it may require a 30 amp breaker to feed the overhead and a 60 amp breaker and heavier wiring to feed the battery. Along with that a special voltage regulator for lithium batteries must also be installed. In the photo below you can see the installation of the breakers and also the wires from the alternator run through an amp sensor to give me an amperage reading on my instrument panel so that I can verify that current is flowing from the alternator during flight verifying that my electrical system is in proper order.