How to Calculate the Maximum Elevation Figure (MEF) on a Sectional Chart Banner Image

How to Calculate the Maximum Elevation Figure (MEF) on a Sectional Chart

Publish Date:
Aug 16, 2018
Flight Foundation

Taking an FAA exam and stumbled across a question involving the Maximum Elevation Figure (MEF)? Wondering how to find the Maximum Elevation Figure for a quadrant of a chart? It turns out that there are two different formulas for calculating the Maximum Elevation Figure based on different terrain.

The Maximum Elevation Figure shows up on a sectional chart as a large number with a slightly smaller number next to it as illustrated in the image above with the red circle. These numbers have two digits dropped off of the end, so [large] 2 [small] 6 is 2,600 feet.

Every half of a degree of latitude and longitude have a Maximum Elevation Figure illustrated on the map, every degree of latitude and longitude has 4 Maximum Elevation Figures calculated based on Terrain and Manmade objects. MEF is calculated using the Mean Sea Level (MSL) elevation on a chart.

Have questions about calculating the MEF or other Part 107 material? Join our Drone Community Facebook Group and ask!

Obstructions Legend on a Sectional Chart.

Maximum Elevation Figure | Terrain Obstructions

Naturally occurring obstructions, such as mountains, we'll find the highest elevation and add 100 feet to allow for error in the overall measurement, add 200 feet for obstruction allowance and finally round up to the next 100 feet.

Let's calculate the Natural Obstruction MEF of this chart

We find the highest terrain elevation in the area to be 2298.

Add 100 feet to allow for vertical error

2298 + 100 = 2398

Add 200 feet for vertical obstruction allowance

2398 + 200 = 2598

Round up to the next 100 feet


Maximum Elevation Figure | Manmade Obstructions

Calculating the MEF of a building or structure is different from naturally occurring obstructions. In man made obstructions, we add 100 feet for vertical error and round up to the nearest 100 feet - and that's all. No tolerance for obstruction allowance.

Let's calculate the Manmade MEF of this chart

We find the highest manmade elevation in the area to be 1623.

Add 100 feet to allow for vertical error


Round up to the next 100 foot mark



While a sectional chart might look overwhelming at first, the more you study the chart and read the information - the more the chart will begin to make sense. Understanding these carts will allow you to know which parts of your area you can and cannot fly, need approval to fly in, elevations you can legally fly and so much more. Even if you aren't applying for a FAA sUAS Part 107, you can appreciate the seemingly insane amount of information that is packed into these sectional charts and use the data to be a better pilot.

What's the hardest part of a sectional chart for you to read?

About the Author:

Keith Knittel

I'm a designer from Cleveland, Ohio and love to shoot photos & videos. I made my first website in 2004 to show friends photos & videos (before YouTube/Flickr were things) and have been shooting and designing ever since! I have a deep passion for making and helping others create.

Free Mavic Mini Getting Started Course

  • Preflight Checklist PDF
  • Free Color Grade LUT Pack
  • Top 10 Tips & Tricks

Free Mavic 2 Pro Getting Started Course

  • Preflight Checklist PDF
  • Question and Answer Videos
  • Get up and running quickly

Post Categories:
Post Tags:

Drone Courses, Community Membership & File Downloads

Shoot Inspiring Images & Connect With Other Students

Drone Training Courses

Learn the entrie process of flying, shooting, editing and sharing.

Learn the do's and dont's, as well as common pilot mistakes and how to fix them.

Private Community Membership

Our privately hosted drone community offers a place to post your work, ask questions and talk to your classmates and your instructor, me!

All skill levels welcome, from beginners to advanced pilots.

Updated Monthly

Drones and technology move pretty quickly. I will add more lessons to the courses every month and update lessons as new information becomes available.

Free Video Courses & Preflight Checklists

Beginner Guides for Specific Drones

Getting Started Guides

Answer common questions and get tips and tricks for your specific drone.

Preflight Checklists

Ensure you're flying safely and have a consistent plan with a preflight checklist. Use these lists to fly safely and not forget anything before and during flight.

Free Courses & Guides
Mavic Mini Mavic 2 Pro/Zoom