A Turn & Bank indicator can be a very valuable IFR instrument, but often gets torn out these days and replaced with backup AI’s. Howard Stark clarified his method on how to fly level using this and one more instrument alone in his 1931 book:
1. Center turn indicator with rudder only.
By using rudder you’ve now stopped the turn, but you don’t know if you’re level on the wings, which can then be derived from:
2. Center ball with ailerons only.
Now that you’ve eliminated any acceleration forces on the ball, it’s just a spirit leveler. You can now level wings using that.
3. Center climb indicator (VSI) with elevator only.
Self explanatory. Would work with altimeter as well, just not as instant.
Now, this does not work on Turn Coordinators as they blend roll and yaw rate, only works on the older style T&B’s. Some old school IFR pilots have sometimes exchanged the newer TC for T&B’s to counter this.
Here’s a link to Howard Starks 1931 book on Instrument Flying. It’s very interesting reading:
Blind or Instrument Flying by Howard Stark
Interestingly, this is also true in an engine out scenario in a twin (one of the last chapters in the above link). His method works equally well there. On top of this, the T&B indicator is also the only instrument that will tell you have to get out of a spin in IMC when an AI would just tumble.
Taking all this in, I nominate the T&B as the most important IFR instrument to have. Who’s with me? 
Why is this method better than stopping the turn with the the ailerons and centering the ball with rudder?
I’ve only briefly flown IFR with just a T&B (in a glider), but applying the same techniques that I would use with a TC seemed to work well.
I humbly suggest that a good starting point is a thorough understanding of the difference between IMC and IFR ;-)
I think that altimeter is a better pitch instrument than VSI. It responds more quickly.
In my experience, a glass AI does not require the 1,2,3 method. It gives the pilot direct attitude information with little need for interpretation. I consider it a better instrument than T&B, especially to prevent and overcome spatial disorientation, arguably the biggest IMC killer, together with CFIT (which can be prevented by adding SynVis to the AI.)
Adam, getting nervous about the reliability of the “new panel”??
You can do that if you have a working Attitude Indicator as backup to give you bank angle information. Because a T&B/TC is rate-of-turn instrument rather than bank angle instrument and it will not tell you on its own if your wings are level, except for in the correct order that Stark devised. If you stop the turn with aileron, then the ball will be susceptible to acceleration/centrifugal forces and you won’t be able to use that as a wing leveling device. As Stark mentions:
The order in which the instruments are observed is absolutely vital, for the ball-bank will give a false index for level flight if the turn indicator is not centered first of all.
Most people install backup AI’s these days, and TC’s before that, so the need to know this has been going away for decades. I just thought it was an interesting reminder that if your AI fails, and you have no other backup, the Stark 1-2-3 method is pretty much your best bet in IMC. It’s a good method to at least be aware of.
Of course a modern AI is useful instrument and in many ways easier to interpret, but it won’t do two vital things:
1. It won’t save you in an inadvertent spin in IMC. T&B and the Stark method is the only thing that will do that.
2. Tell you which engine has quit in IMC.
Adam, I know that you post it for historical reasons but an instrument to enable recovery from an inadvertent spin in IMC is so far down the list of priorities in my opinion that it isnt even worth discussion. The likelihood of someone who enters a real-life spin in IMC being able to carefully recover using a T&B is next to nil. If you enter a spin in IMC you are likely to be very close to the ground doing an approach so a recovery is nearly impossible anyway.
Isn’t using the T&B indicator part of partial panel ? When the AI doesn’t work, you can fly with VSI and T&B.
Isn’t using the T&B indicator part of partial panel ? When the AI doesn’t work, you can fly with VSI and T&B.
I think that the point that Adam is making is that it is the modern view that the T&B can be eliminated from the panel if you have a backup AI entirely independent of the primary one.
For example, in my aircraft I have an Aspen, which is electrically and electronically driven, and I also have two suction driven AIs. It is hard to imagine a scenario where I would lose all my attitude information, so I have allowed both my rate instruments to fall into disrepair.
In the aircraft I manage, there is a primary G600, a backup glass AI/DG and a suction AI on the other panel. In that case the rate instrument has been completely removed.
Partial panel on these aircraft is achieved with backup attitude instruments rather than rate instruments.
ok yes, make sense
