If you wish to contribute or participate in the discussions about articles you are invited to join SKYbrary as a registered user
Minimum Obstacle Clearance Altitude
From SKYbrary Wiki
| Article Information | ||
|---|---|---|
| Category: | General | 
|
| Content source: | SKYbrary | 
|
| Content control: | EUROCONTROL | 
|
Minimum Obstacle Clearance Altitude (MOCA)
Definition
The MOCA is the minimum altitude for a defined segment that provides the required obstacle clearance. A MOCA is determined and published for each segment of the route. (ICAO Doc 8168 PANS-OPS)
Description
The MOCA provides the required clearance above obstacles contained inside the obstacle clearance areas. Charting accuracies are taken into account when establishing minimum altitudes by adding both a vertical and a horizontal tolerance to the depicted objects on the chart.
The minimum obstacle clearance value to be applied in the primary area for the en-route phase of an IFR flight is 1000 ft (300 m). In mountainous areas, the minimum obstacle clearance applied is as follows:
| Terrain Elevation | Obstacle Clearance |
| 3000 ft - 5000 ft (900 m - 1500 m) | 1500 ft (450 m) |
| Greater than 5000 ft (1500 m) | 2000 ft (600 m) |
For information concerning the construction of the obstacle segment see ICAO Doc 8168, PANS-OPS, Part I, Section 5.