You might be thinking of a spiral dive. A spiral dive is what disoriented pilots in IMC often get into, and if you don’t have your wits about you it can really ruin your day.
The problem is that in a spiral dive your butt feel is like you are going straight and level, but your airspeed and feel of the airplane is telling you to pull up.
It will appear that the artificial horizon has failed (it will usually be indicating the truth, but it will feel wrong and you will think it’s broken, or it may be past it’s gimbal lock limits. )
If you follow your instincts, you will try to pull up. That will have the effect of tightening the spiral component of the dive but will not cause the aircraft to regain level flight. It will also have the effect of drastically increasing the stress on the airframe, which may already be beyond its maximum structural speed.
Recovery from a spiral dive is very easy… but you have to know you are in a spiral dive, and without visual reference to the ground that requires awareness and correct interpretation of the flight instruments.
You are in a spiral dive if:
A: you are going at an inexplicably high speed for your engine and airframe configuration (you are in a dive). Most pilots recognise this easily.
And
B: your rate of turn indicator is off center or especially, pegged to one side. You have to be looking for this.
Aside from that, a rapid descent showing on the VSI and altimeter.
Other gyroscopic instruments such as the heading indicator and the artificial horizon may be showing erratic or incorrect information.
Recovery is easy:
1: immediately pull the throttle to idle.
2: neutralise the turn that is indicated on the turn indicator using normal control inputs. Do not attempt to pull up until the turn has stopped completely.
3: gently pull out of the dive. Avoid abrupt control movements until the aircraft is below manoeuvring speed.
4: continue to fly the aircraft. If you are in clouds consider carb heat to avoid icing.
