"Oh look, there's an ODP!" - no one ever
"You're an IFR pilot. Stop whining!" - Dr. Bill
^Yes, those are goats.
What is this thing?
An Obstacle Departure Procedures, abbreviated as "ODP", is a prescribed route that allows pilots to depart an airport under IFR without risking colliding with obstacles. Because departures from an airplane could occur in multiple ways, it usually provides guidance for specific turns.
For example, if there is an obstacle to the right of the departure end of the runway, the ODP might specify "climb to 1500 before turning right". This implies that turns to the left (after reaching 400 ft) or climbs straight ahead are perfectly fine.
How do you know if there is an ODP? Well remember that "T" in the upside down triangle that you see on IAPs? Well that means that the airport/runway has either nonstandard Takeoff Minimums, an Obstacle Departure Procedure, a Diverse Vector Area, or Low, Close-in Obstacles. These are found in the "TAKEOFF MINIMUMS (OBSTACLE) DEPARTURE PROCEDURES, AND DIVERSE VECTOR AREA (RADAR VECTORS)" publication which you can find in Forelight or Garmin Pilot (or by searching here):
Here is an ODP for Beaufort Executive Airport (KARW) in South Carolina. Note under 'DEPARTURE PROCEDURE':
There are two ODPs, one for runway 07 and one for runway 25. In the case of runway 7, it says to climb runway heading to 1700 before turning right. This means that the pilot can turn left (after reaching 400 ft AGL) or fly straight ahead without any obstruction departure.
When do I need to fly one?
Well, under Part 91 (yeah, you) we are not required to fly one. So why are they published, then? When the FAA surveys an airport for IFR approaches, they also do what is called a “diverse departure assessment,” the picture below from the IFH (and the one from the AIM is better with billygoats). If you can get to 400 AGL and turn in any direction, while doing 200 ft/NM, then no ODP is necessary and none is published (so all turns allowed at 400 ft AGL). If this can’t be met, then the FAA publishes an ODP, be it for a towered airport or non-towered airport. ATC can however take responsibility for separation and clearance from obstacles if there is a published Diverse Vector Area (DVA).
Since pilots may or may not be flying an ODP (without advising ATC) under part 91, a pilot should expect to be advised by ATC if those instructions are contrary to the ODP; but, if ATC does not do this, remember they go home at night with a bad performance review (except KSAV's AF or JG, of course) but you may hit a mountain—thus, it is the PIC's job to verify the departure plan. Furthermore, remember that if the airport has an ODP and also publishes a diverse vector area (DVA), ATC may provide vectors under radar contact contrary to the ODP, since ATC assumes the responsibility for aircraft separation and terrain.
Ok, so here's the breakdown. If your airport has published IAPs and no ODP, then you can make any turn at 400 ft AGL. If your airport has an IAP and an ODP, then follow it. If your airport has an IAP, an ODP, and DVA, then you can expect departure instructions that go against the ODP (and that's ok). Here is a flowchart:
How do I fly one?
Examples
Example 1: KBIL - Billings, MT (towered)
If ATC says “fly heading 360” and you are departing runway 10L, when do you turn (Billings field elevation is about 3,600 feet)? Well, it has IAPs, no published DVA, so not until 4,600 feet, as published in the ODP (there is also a published SID, which aligns with this ODP by the way).
Example 2: KSAV - Savannah, GA (towered)
Example 3: KSAV - Savannah, GA (towered)
Example 4: KARW - Beaufort, SC (untowered)
Example 5: KUAO - Aurora, OR (towered)
Example 6: KVDI - Vidalia, GA (untowered)
The Bottom Line.
The bottom line with airports with ODP, especially towered: If in doubt about what ATC expects you to do after departure, clarify with ATC. And if you think that checking ODPs every time you fly is annoying, I'll quote Dr. Bill:
The next confusing part of this story are “low close-in obstacles,” but that will be in a future post...
Thank you to these awesome people who helped me write this article.
Dr. Bill, my fearless CFII (yes I still ask him questions cause he is all-knowing and has demigod status).
AF, my favorite controller (who tolerates me a lot and is instantly happier when he hears my voice on radio)
JG, my co-favorite controller (he says "what 'ya got?" when I have interrogatives. And he also tolerates me a lot. And recognizes me on radios, so he makes me feel thpethal)
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