i. Standard case. Where no obstacles penetrate the 2.5% obstacle identification surface and 300 ft (90 m) of obstacle clearance prevails, a 3.3% climb to 400 ft (120 m) will satisfy the obstacle clearance required for a turn in any direction (see Area 1).
ii. Specified turn altitude or height. Where obstacles preclude omnidirectional turns at 400 ft (120 m), the procedure will specify a 3.3% climb to an altitude or height where the omnidirectional turns can be made (see Area 2).
iii. Specified procedure design gradient. Where obstacles exist, the procedure may define a minimum gradient of more than 3.3% to a specified altitude or height before turns are permitted (Area 3).
iv. Sector departures. Where obstacles exist, the procedure may identify sectors for which either a minimum gradient or a minimum turn altitude or height is specified.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved