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What Does It Mean To 'Maintain Your Own Terrain And Obstruction Clearance'?

Have you ever wanted to pick up an IFR clearance in the air, but clouds prevent you from visually climbing to the minimum IFR altitude above you? There is a way, but it comes with a lot of serious considerations. Here's what you need to know...

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ATC Is Responsible For You Under IFR

When you fly under IFR, Air Traffic Control is responsible for providing you with traffic, terrain, and obstruction clearance.

To ensure you maintain safe terrain and obstruction clearance, controllers will have you fly either a published procedure, or fly above the minimum instrument altitude (MIA). Here are some examples of procedures and altitude constraints that will keep you clear of terrain and obstacles:

Each of these procedures and altitudes will keep you clear of terrain and obstructions, but differ in terms of required separation based on airspace dimensions and nearby terrain.

For example, the MEA along a victor airway might be much lower than the sector's OROCA. This is simply because the victor airway has much smaller dimensions than an entire sector of the map. Terrain may not be a factor along the path of a particular victor airway, even with mountains 10 or 20 miles away.

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Trapped Below The Clouds? You Have An Option.

So here's the scenario. You begin a cross country flight out of Rifle, Colorado. Anticipating good conditions along your route, you decide to fly VFR. As you begin flying, you realize that to climb any higher you'll need to pick up an IFR clearance. Because you don't want to break cloud clearance requirements, you decide to pick up a pop-up IFR clearance.

Due to mountains in the sector, the OROCA for your IFR clearance will be quite high - 16,300 feet. When you call ATC for your clearance, the controller tells you to maintain VFR until reaching 17,000 feet. You estimate the clouds are at 12,000 feet, still way too low to make a VFR climb all the way above the OROCA.

So what should you do? Do you climb through the clouds to 17,000 feet, or cancel your request because you know you can't maintain VFR during your climb?

It's Called: "Own Terrain And Obstruction Clearance"

FAA Order JO 7110.65X is the rule book for air traffic control procedures and phraseology. Section 4 details the procedures for ATC clearances. When you take a look at 4-2-8 "IFR-VFR And VFR-IFR Flights," you'll find an exception to the normal requirements for IFR terrain and obstruction clearance.

Section (d) states: "When VFR aircraft operating below the minimum altitude for IFR operations requests an IFR clearance and the pilot informs you, or you are aware, that they are unable to climb in VFR conditions to the minimum IFR altitude:

1. Before issuing a clearance, ask if the pilot is able to maintain terrain and obstruction clearance during a climb to the minimum IFR altitude.

2. If the pilot is able to maintain their own terrain and obstruction clearance, issue the appropriate IFR clearance as prescribed in Para 4-2-1, Clearance Items, and Para 4-5-6, Minimum EnRoute Altitudes.

3. If the pilot states that they are unable to maintain terrain and obstruction clearance, instruct the pilot to maintain VFR and to state intentions.

4. If appropriate, apply the provisions of Para 10-2-7, VFR Aircraft In Weather Difficulty, or Para 10-2-9, Radar Assistance Techniques, as necessary.

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Correct Phraseology Is Key

Controllers will typically address the situation like this:

"N123AB, Are you able to maintain your own terrain and obstruction clearance until reaching ____ (appropriate MVA/MIA/MEA/OROCA)"

In normal use, the radio transmission you'll hear might sound like:

"November Eight Seven Six, are you able to provide your own terrain and obstruction clearance between your present altitude and six thousand feet?"

As the pilot, if you acknowledge and accept this instruction, you are responsible for your own terrain and obstruction clearance, even in the clouds. ATC will not be able to issue you the same level of protection that you would receive under normal circumstances. On top of that, ATC radar systems often do not have a low-altitude warning systems when you're flying below the MIA and approaching terrain or obstacles. If you accept the clearance, you're largely on your own to make sure your maintain terrain and obstruction clearance, even when you're in the clouds.

Safe Decision Making

If you decide to accept this clearance, you need to take a few things into consideration.

  • Do you have adequate knowledge of the surrounding terrain?
  • Are you on a course that provides minimum IFR clearance from terrain/obstructions below you? (1,000' within 4 miles of your course, 2,000' in mountainous terrain)?
  • Do you have equipment onboard that will provide situational awareness and separation from nearby terrain and obstructions?
  • Does your aircraft have the performance required to out-climb terrain?
  • Will there be terrain or obstacles above you when you enter the clouds?

If you are unsure about the answers to any of these questions, the safest option will always be to find an alternate option or divert.

Useful Departure Options: Airports Without ODPs And Poor Radar Coverage

If you're picking up an IFR clearance with "own terrain and obstruction clearance" on the ground, it's usually because the airport does not have a published ODP, and you're in an area that has poor radar coverage. ATC may ask if you can maintain your own terrain/obstruction clearance if that's the case. When a controller isn't confident that radar coverage will be sufficient to keep a good eye on you, this is one way they can clear you out of an airport under IFR.

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What Would You Do?

Would you take terrain and obstruction clearance into your own hands while flying in IMC around terrain? What about departing from an airport with no terrain or obstacles nearby? Tell us in the comments below.

Swayne Martin

Swayne is an editor at Boldmethod, certified flight instructor, and commercial pilot for Mokulele Airlines. In addition to multi-engine and instrument ratings, he holds a PIC Type Rating for Cessna Citation Jets (CE-525). He graduated as an aviation major from the University of North Dakota in 2018. He's the author of the articles, quizzes and lists you love to read every week. You can reach Swayne at swayne@boldmethod.com, and follow his flying adventures at http://www.swaynemartin.com.

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