Welcome Guest. Sign in or Signup

4 Answers

What is clearance slope?

Asked by: 6527 views , , ,
Airspace, General Aviation

What is clearance slope and how can I use that information as a VFR pilot?

4 Answers

  1. Nathan Parker on Feb 08, 2012

    Please give more context, since there are a number of concepts which could reasonably be described as “clearance slope”.  These terms generally mean that there is an inclined plane starting from some location to another through which no obstacles can penetrate.  These typically apply to instrument flight and don’t affect VFR pilots.

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes

  2. Jason on Feb 08, 2012

    Here are examples of what I’m asking about:
    “Tree, 550 ft Left of center, 59 ft high, 1,900 ft from end, 29:1 clearance slope.””Pole, 400 ft Left of center, 30 ft high, 975 ft from end, 26:1 clearance slope” 
    What does 29:1 or 26:1 translate to?  What are other ways to say the same thing? 

    0 Votes Thumb up 0 Votes Thumb down 0 Votes

  3. Best Answer

    Nathan Parker on Feb 08, 2012

    For every 29 feet of horizontal distance, you need to climb 1 foot to clear those obstacles.  And that assumes that you start at the departure end of the runway.  If you’re climbing out at 75 knots, you need a climb rate of about 160 ft/min.
    Still, VFR, you can visually avoid the obstacles even if you can’t outclimb them.  It’s more relevant when you’re taking off IFR and can’t see anything.

    +6 Votes Thumb up 7 Votes Thumb down 1 Votes

  4. Derek Schwalenberg on Feb 10, 2012

    Yeah you know by the performance charts whether or not you can clear the trees/obstacle. As far as other things like mountains, antennas, and the like you can simply maneuver around them if you don’t wait till the last second. It’s when you cannot see these things that you have to check the old chart on the inside back cover of the instrument approach plates. Remember, if its moving down in the windscreen you will pass over it hopefully with a good margin (assuming you maintain the current situation), if not then you better bank the airplane away from it!

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes

The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.