O Como voa na seção Recuperação de mergulho em espiral menciona:
If you don’t have good outside references, you should not rely on the attitude indicator (artificial horizon). The attitude indicator contains a gyro mounted on ordinary mortal gimbals, which can only accommodate a limited range of pitch and bank angles. A steep spiral can easily cause the gyro to tumble, whereupon it will need several minutes of relatively straight and level flying before it can re-erect itself. Military aircraft have non-tumbling attitude indicators, but you’re not likely to find such things in a rented Skyhawk. Therefore, you should roll the wings level by reference to the rate-of-turn gyro.8 Being a rate gyro (as opposed to a free gyro) it has no gimbals, and therefore can’t possibly suffer from gimbal lock.
8 That is, the turn needle or turn coordinator, whichever you happen to have.
E na seção sobre Spin Recovery , ele adiciona:
If you get into a spin in instrument conditions, you should rely primarily on the airspeed indicator and the rate-of-turn gyro. The inclinometer ball cannot be trusted; it is likely to be centrifuged away from the center of the airplane — giving an indication that depends on where the instrument is installed, telling you nothing about the direction of spin. The artificial horizon (attitude indicator) cannot be trusted since it may have tumbled due to gimbal lock. It is better to trust the rate-of-turn, which cannot possibly suffer from gimbal lock, since it has no gimbals. Remember, it is a rate gyro (not a free gyro), so it doesn’t need gimbals.
Se você tem horizonte artificial bom o suficiente projetado para evitar o bloqueio do cardan, você não precisa de coordenador de curva. Mas com o horizonte artificial comum, o coordenador de giro combinado com o indicador de velocidade vertical (apesar de seus problemas, como o tempo de reação mais lento), é um backup útil para se recuperar de transtornos em vôo.