Any idea what that red switch is?  This airplane is a Diamond DA-40 with a Garmin G-1000 system.  The red switch is for activating the emergency battery power for the attitude indicator to the right of the airspeed indicator.







The battery pack is mounted behind the copilot’s instrument panel, and it must be changed every 2 years, as required by an “Airworthiness Limitation” in the DA-40 maintenance manual.  This is not optional, but mandatory.




So, what is an “Airworthiness Limitation?”

It is an FAA approved requirement for maintaining the airworthiness of an airplane.

Check out this website to see some good information regarding recommended vs. mandatory:

91.403(c) No person may operate an aircraft for which a manufacturer’s maintenance manual or instructions for continued airworthiness has been issued that contains an Airworthiness Limitations section unless the mandatory replacement times, inspection intervals, and related procedures specified in that section … have been complied with.

Some other items on this Diamond DA-40 that are affected by “Airworthiness Limitations” are:

Garmin G1000 system as installed in the DA-40:  Mandatory replacement of the 5 slow blow fuses in the system, as well as some other specific checks of the flap and autopilot system.

Powerflow Exhaust System:  Mandatory lubrication of the slip joints every year, which requires removal of the exhaust system.

AmSafe Inflatable Seatbelts:  Mandatory system checks, and replacement of the inflators and the EMA (Electronic Module Assembly.)

These previous 3 items are not in the Chapter 4 Airworthiness Limitations section of the Diamond Maintenance manual.  But rather, they are in the specific ICA documents for these components.

So, this is one example of how important it is to be familiar with the ICA’s for the modifications in your airplane.

How about your airplane?  Are all the “Airworthiness Limitations” being complied with?

Listen to today’s episode for more information.

Hey, one more thing… If you haven’t left a rating and review in iTunes for this podcast, could you take a minute and do that?  I would be so grateful!