Instrument Flight Procedures: Departure, En-route and Arrival
This domain tests whether you can design and fly a procedure from the charted criteria, not just read it. You must understand the standard instrument departure structure, the obstacle clearance surface, the minimum obstacle clearance (MOC) concept, and the difference between a straight departure and one requiring a specified climb gradient or turning departure.
Concepts to master
- Standard departure: initial climb to 400 ft above the aerodrome before turning unless a published procedure says otherwise.
- Climb gradient: percent versus feet per nautical mile; the relationship to ground speed and rate of climb.
- En-route: minimum en-route altitude, minimum obstacle clearance, and the significance of the MORA grid.
- Arrival and approach: initial, intermediate, final and missed approach segments; the MOC each segment provides; the missed approach point definition.
- Procedure design traps: the difference between a charted altitude and a charted height, and between DA/H and MDA/H for the approach type.
Common traps
Questions often quote a gradient in percent and a speed in knots and expect a rate of climb. Another favourite is the turn after departure: candidates assume a turn at 400 ft is always allowed, but a published procedure may require a higher altitude or a specific gradient first.
Rule of thumb
Rate of climb (ft/min) = gradient (ft/NM) x ground speed (kt) / 60. For a 5% gradient at 120 kt, that is about 600 ft/min.
Worked example
A departure requires 5.5% to 3000 ft. At a ground speed of 110 kt: 5.5% is about 334 ft/NM; 334 x 110 / 60 gives roughly 610 ft/min. If your helicopter cannot sustain that, the departure is not available to you.