Instrument Departure

1. How to get departure clearance?
a. In towered airport (Class B,C,D), get it from clearance delivery via radio;
b. In non-towered airport (Class E, G), get it from FSS via phone, or directly from an ATC facility via radio. This clearance has a void time.

Void time: at non-towered airport, you must take off before this void time. If not, notify ATC immediately. (Call FSS by phone)

2. Departure heading.
a. IFR clearance only clears you to certain limit
b. In controlled airspace, ATC will assign vectors to that limit
c. In uncontrolled airspace, it’s pilot’s responsibility to select a route so that the departure to that limit is safe

3. How to depart in uncontrolled airport under IMC?
a. Wait till VMC and do a VFR departure, or
b. use a sectional chart to decide on an obstruction-free path in IMC, or
c. use Obstacle Departure Procedure (ODP)

4. When is there an ODP for an airport?
When obstacles penetrate the 40:1 climb plane (152ft/nm) starting at 35 feet above the end of the runway, OPD is provide for that airport.

5. Where can I find ODP?
In section C, or at the end of approach plates (if graphic).

6. When to use ODP?
a. When ATC doesn’t specifically tell you how to depart the airport. (applies for both towered and non-towered airports)
b. ATC is NOT responsible for obstacle avoidance in Class G even if he is talking with you and you are on IFR flight plan. ATC has no jurisdiction over Class G.
c. In controlled airspace (Class B,C,D, E), ATC do assign ODP in the clearance.

7. What airplane performance is expected for ODP?
a. Climb at least 200 feet/nm
b. If a turn is required, climb to a minimum of 400 feet above the departure end of the runway before commencing the turn

8. If there is no ODP,
a. there is no obstacle penetrating the 152ft/nm line
b. there is probably no instrument approaches for this airport

9. What is SID?
Standard Instrument Departure. Used at busy airport to easily communicate ATC clearances to pilot. Just like STAR.

10. Departure procedure (DP) includes both SID and ODP. They are only lateral guidance. ATC assigns altitude. Altitude numbers on DPs are only advisory. The same applies to STARs.

11. What is the weather minimum for instrument takeoff.
a. Standard takeoff minimum: at least 1sm visibility (RVR of 5000 feet) for two engines or less; at least 1/2sm visibility (RVR 2400 feet) for airplanes more than two engines.
b. non-standard takeoff minimum. Trouble “T” in the approach plates and section C.
c. These minimums only apply to part 121, 123, 129 and 135 operators. Do NOT apply to part 91 operators. Part 91 can do 0/0 instrument takeoff.

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