In 2003, mechanical and maintenance were the major cause of 15% of all GA accidents, and 7.5% of fatal accidents

Typically, one mistake or failure—a precipitating event—leads to another in a cascading series of malfunctions and mistakes, culminatiing in an accident. This is called the accident chain.

By any calculation, the average pilot could fly many, many lifetimes without having an accident of any sort, let alone a much more rare fatal mishap.

In 2003, electrical/ignition failures accounted for 3% of all accidents, and 0% of fatal accidents.

2004 Nall Report

  
 

CIRRUS Monthly Proficiency Program
3 part series on IFR operations
August – Part 1: Electrical Systems


Electrical System Abnormalities (continued)

Volt/Amp Meter
The ammeter in the SR20 and SR22 is located on the right side of the instrument panel. It serves three purposes:

  1. Measure voltage on the Essential Bus
  2. Measure amps on ALT 1
  3. Measure amps on ALT 2

A toggle switch above the Volt/AMP Meter allows you to select between three positions:

  1. ALT 1
  2. BATT, or
  3. ALT 2

ALT 1 or ALT 2. When the toggle switch is in the ALT 1 or ALT 2 position, you’ll see the amperage of that alternator and the voltage on the Essential Bus. When the toggle switch is in the BATT position, it reads the amp draw on BAT 1, which should be zero if you have a fully charged battery. The voltage is still on the Essential Bus.

BAT 1. If BAT 1 is low and ALT 1 is charging the battery, the amp meter needle shows positive. If ALT 1 has failed, the amp meter needle shows negative. In the event of an alternator failure, you can verify the failure by toggling the amp switch to select the desired alternator and determine if there is a load on that alternator. If there is no load on the desired alternator, it will indicate zero amps. You can also use the engine monitoring page on the MFD to view voltage on the Main Distribution and Essential Buses.

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