WHY CONSIDER A TURN
AIRPORT DEPARTURE PROCEDURES FOR OBSTRUCTION CLEARANCE ASSUME THAT AIRCRAFT ARE CAPABLE OF MAINTAINING A CLIMB PROFILE WHICH IS NORMALLY ACHIEVABLE WITH ALL ENGINE CLIMB PERFORMANCE. CONTINUED ADHERENCE TO DEPARTURE PROCEDURES MAY NOT BE POSSIBLE IN THE EVENT OF AN ENGINE FAILURE.
CONTINGENCY PROCEDURES MAY BE REQUIRED TO PROVIDE FOR ANY SITUATION OCCURRING DURING THE DEPARTURE PROCEDURE IN WHICH THE AIRCRAFT BECOMES UNABLE TO MAINTAIN SPECIFIED CLIMB GRADIENT.