I-4-1-10
Procedures — Aircraft Operations — Volume I
NON-PRECISION APPROACH Altitude
Minimum descent altitude (MDA) or Minimum descent height (MDH)
Margin or Lower limit Based on operational consideration of: – ground/airborne equipment characteristics – crew qualifications – aircraft performance – meteorological conditions – aerodrome characteristics – location of guidance aid relative to runway – etc. For details see Annex 6.
Obstacle clearance altitude (OCA) or Obstacle clearance height (OCH) MDA MDH OCA
Minimum obstacle clearance (MOC) for the final segment
OCH
Fixed margin for all aircraft 90 m (295 ft) without FAF 75 m (246 ft) with FAF (FAF = final approach fix) Note.— MOC may include an additional margin in mountainous terrain and is increased for excessive length of final approach segment and for remote and forecast altimeter settings. The height of the highest obstacle in the final approach. Note.— Identification of obstacles according to areas associated with type of facility used in the procedure. Aerodrome elevation or threshold elevation if more than 2 m (7 ft) below the aerodrome elevation
Mean sea level
Figure I-4-1-3. Relationship of obstacle clearance altitude/height (OCA/H) to minimum descent altitude/height (MDA/H) for non-precision approaches (example with a controlling obstacle in the final approach)
23/11/06