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how do attitude indicators, turn and slip ind and turn coordinator on ground

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Flightsurgeon created the topic: how do attitude indicators, turn and slip ind and turn coordinator on ground

Hi all just wondering what the behaviour of these instruments is on the ground as I think there was a questions somewhere on my travels on this topic

1. Im presuming on the ground, the attitude indicator doesnt indicate a turn
but turn and slip indicator will turn in the direction of turn. However im not sure if the turn coordinator will turn left or right on the ground when turning left or right because this instrument I believe senses yaw and roll.

can someone please assist

2. also on the ground, the balance ball, when an aircraft turns, is the ball centered? ( because Im presuming on ground the turn is coordinated )

Please help and many thanks

R
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  • John.Heddles
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John.Heddles replied the topic: how do attitude indicators, turn and slip ind and turn coordinator on ground

on the ground, the attitude indicator doesnt indicate a turn

The A/H never indicates a turn. All it does is indicate bank angle and pitch angle (within its toppling limits, if any). Usually, with a bank indication, the A/H indications may be associated with a turn, but not necessarily. Think of a savage side slip on final to lose some height or wash off some speed.

turn and slip indicator will turn in the direction of turn.

The turn indicator will so indicate. The slip (or balance) indicator knows naught about turns.

not sure if the turn coordinator will turn left or right on the ground when turning left or right

It sure does. One of the basic preflight taxy checks for IFR (and it should so be also for VFR) is to check that the cards (heading indicators), needles (ADF/VOR) and turn indicator are following taxy turns and that the slip ball has moved to the outside of the turn.

on the ground, the balance ball, when an aircraft turns, is the ball centered?

No, see previous comments. The ball is just a ball running in a track with some dampening to make it a bit more sensible. If you turn on the ground, the centrifugal reaction sees the ball move to the outside of the turn.

I'm presuming on ground the turn is coordinated

Thoughts of co-ordinated turns only apply in flight. An aircraft on the ground is no different to a Formula One racer, (only hopefully, a tad slower). When we talk about co-ordinated turns, we are considering the situation when the net vertical force is perpendicular, when viewed from the reference frame of the aircraft. That is to say, the net "weight" acts straight "down" between your feet and not directed toward the earth's centre.

Eventually, we'll get you out of the OR and into a heavy jet ....

Engineering specialist in aircraft performance and weight control.
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Flightsurgeon replied the topic: how do attitude indicators, turn and slip ind and turn coordinator on ground

as ever magnificent advice and thanks
Once I get my PPL, Ill get out of theatre a little more!
Not sure about a heavy jet, Ill work on a 172 first!!!
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  • John.Heddles
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John.Heddles replied the topic: how do attitude indicators, turn and slip ind and turn coordinator on ground

Not sure about a heavy jet, Ill work on a 172 first!!!

Some differences .. but, in essence, Mr Boeing's products fly much the same as your C172.

Engineering specialist in aircraft performance and weight control.
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