Should I rely on vacuum attitude indicator in IMC or the turn coordinator?

[AriaT]

I’ve been flying a Cessna 172 for my instrument training, and I’ve noticed the vacuum-driven attitude indicator can sometimes be a bit sluggish or give a slightly false indication during steep turns. It makes me wonder how much I should really be relying on it compared to the electric turn coordinator, especially in actual IMC when things get bumpy.

[Paisley_H]

Absolutely. In steep turns the vacuum driven gyro can feel a beat late, especially when the air is choppy. I treat that gyro as the horizon picture you’re connected to, but I don’t trust it alone in IMC. The electric turn coordinator is usually steadier on rate of turn, so I keep a quick cross-check: the gyro for bank and pitch, the turn coordinator for turn rate, and the standby VSI as a sanity check.

[JustinM]

Sometimes I wonder if the problem is really the instrument or the perception under stress. In a recent flight the AI looked lazy in a 60 degree bank, but the turn coordinator held the turn rate fine. I paused, recalibrated, and still felt off. Maybe I over-rode the cross-check or the whole problem was my own expectations.

[Steven31]

One concrete thing I did was watch the suction gauge during a gentle coordinated turn and note how the readings matched the gyro responses. It was different from the simulator, which makes me doubt whether the training data lines up with real operations.

[Kenneth_M]

One question for you: do you have a standby attitude indicator you trust or a second source you bring online when the vacuum system feels off?