Answer for DAPT
DAPT asks: "How does a UK trained pilot end up with rotors not turning ?"
In forward flight:
1. Fenestron fail.
2. Turn down engine power.
3. Fail to move cyclic in direction opposed to airflow.
4. Airflow stops rotor.
Note - In order to see this you need to think outside the box. Imagine a model helicopter in powered forward flight and see the airflow vectors. Then see it morph into an autogyro with same c of g velocity but totally different attitude and airflow vectors. Without the attitude change the airflow stops the rotor.
Not a pilot, just a dull old engineer, never seen this problem before.