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Feature Article 2


Max Trescott, WVFC CFI

I specialize in teaching in glass cockpit aircraft and I now spend most of my time in G1000-equipped aircraft and in Cirrus SR20 and SR22 planes. Concentrating my flight hours in these planes has helped me discover where people consistently encounter issues. And some of the Insights I've gleaned from teaching at West Valley have ended up in my Max Trescott's G1000 and Perspective Glass Cockpit Handbook, now in its fifth edition.

For example, half the time I climb into a G1000-equipped plane, I find that the standby attitude indicator is set incorrectly. You’ve probably noticed the same thing…even if you’re in the group of people setting it incorrectly!

In non-glass cockpit planes--those equipped with six round gauges--pilots are accustomed to setting the attitude indicator so that the orange dot is on the horizon, which is a horizontal white line that runs across the center of the instrument. If however you set the standby attitude indicator in a G1000-equipped plane the same way--with the orange dot on the white line--you're setting it incorrectly.

The correct way to set the standby attitude indicator is to first look at the Primary Flight Display (PFD) and determine how many degrees the aircraft is pitched up. Typically while on the ground, a Cessna 172 is pitched up about 2.5 degrees. Therefore the orange dot on the standby attitude indicator should be set to 2.5 degrees, not to the zero line.

Another common issue is a lack of understanding of the manual squelch on the intercom. Squelch is the feature that eliminates the background noise coming through your headset microphone when you’re not talking. If the squelch setting is too “loose,” you’ll hear continuous background noise. Or, if the squelch is set too ”tight,” the first syllable you speak won’t be heard, as the squelch is opening late. In the extreme, if the squelch is way too tight, it won’t open at all and you’ll never hear yourself speaking on the intercom. Fortunately, none of this affects how well you hear, or are heard, when you’re transmitting on the radio.

The G1000 has an automatic squelch, but it’s generally a little tight for most headset microphones and it clips your first syllable. To get around this, you need to set the manual squelch.

I often hear people saying “test one two” as they adjust the squelch control, but this won’t give you a precise setting. Instead to get the most precise squelch setting, you and your passengers shouldn’t be talking at all!

To start, push the MAN SQ key on the audio panel. Then make sure the intercom volume is turned up so that you can clearly hear any background noise. To do this, look at the concentric knobs at the bottom of the audio panel and make sure the VOL annuciator to the lower left of the knobs is lit. Generally, the background noise is louder coming from the pilot side and you may have to turn the volume up fairly high to hear the background noise coming from the copilot’s microphone.

Then push the center knob so that the SQL annuciator to the lower right of the knobs is lit. Grab both knobs and turn both counterclockwise until you hear plenty of noise in your headset. Then adjust each knob individually. I start with the center knob that controls the pilot’s squelch and I turn it slowly clockwise to the point where the background noise just goes away. Then if I’m on the ground, I’ll turn the knob one more click clockwise. If you don’t do that, the squelch will open when you take off, due to the higher noise levels.

Set the outer knob, which controls the copilot and passenger squelch, the same way. Turn it slowly clockwise to the point where the background noise just goes away and then add one additional click if you’re on the ground when you set it. When you’re done, press the center knob so that the VOL annuciator is lit. Finally, DON’T push the MAN SQ key, or you’ll undo everything you’ve just done!