Subscriber question:
"If I'm departing IFR from a towered airport on a runway that has a published ODP and Tower just gives me a heading to fly that's not part of the ODP, do I follow the ODP before flying that heading?" —John H.
Kevin:
“Good question, simple answer: Fly the heading given to you by Tower and do not fly the Obstacle Departure Procedure (ODP).
Take a look at AIM 5-2-9: ‘ODPs are recommended for obstruction clearance and may be flown without ATC clearance unless an alternate departure procedure (SID or radar vector) has been specifically assigned by ATC [emphasis added].’ The heading assigned by Tower falls under the category of ‘radar vector’ and guarantees obstacle clearance so long as you meet the standard climb gradient for IFR departures of 200 feet per NM. ATC can assign headings in any direction where the standard climb gradient will be adequate to clear the standard 40:1 obstacle clearance slope.
In situations where obstacles penetrate the 40:1, a Diverse Vector Area might be established per FAA Order 7210.3 3-8-5. If these Diverse Vector Areas require a climb gradient greater than standard, the steeper gradient will be published in the same place you’ll find the ODPs. Nothing is published if only the standard climb is required. You just have to trust ATC on it.
Of course, I always recommend reviewing your departure route on a Sectional Chart for terrain or obstructions that might be a problem for you on climbout. That’s true whether it’s an ODP or a heading assigned by Tower—even if you must delay your departure a moment to check.”