ESDU 67005 introduces the subject of inertia cross-coupling and describes some of the simplifications to the equations of motion that are used for rapid rolling manoeuvres. A discussion of the importance of the terms in the aircraft motion equation is given together with a description of the stability aspects of the problem. ESDU 67006 and ESDU 67007 discuss the theoretical background and the simplified stability boundaries@ and give a means of estimating the critical roll rate.