PROVISION VALUE MAXIMUM ELEVATION FIGURE (MEF) 

VALUE ON INDOAVIS VFR CHART.

 

UNDERSTANDING  OF MEF

Maximum elevation figure or MEF is the a type of VFR altitude which indicates the height of the highest feature within a quadrangle area. It is of interest to pilots, who want to be aware of the highest mountain peaks and tall towers nearby, so that they can fly above them to avoid controlled flight into terrain.

MEF information is required for the entire soil mass/terrain, trees, towers and open water areas that contain man-made obstacles (such as gas/oil rigs and large buildings). In a VFR context, this altitude is commonly referred to as a "quadrantal altitude"

 

MEF CRITERIA

MEF featuring the highest elevation, natural or man-made, in a rectangle bounded by lines specifically marked (latitude and longitude) of a network of fine lines and should be centralized in each quadrilateral described.

MEF  figures  shall  be composed of the thousand feet digit (s) and a smaller hundred foot digit. Zero thousands shall be shown with a larger thousand foot digit of zero followed by the smaller hundred foot digit. Zero hundreds shall be shown with a smaller hundred foot digit of zero. The last two digits of the number shall be omitted.

 

METHODS  OF  COMPUTATION

In  determining the MEF, extreme care should be exercised to increase such figures only to the point where it is assured that they represent a safe flying altitude based on the existing elevation data shown on the source data/material.

MEF Value is determined by taking the highest elevation point in the quadrangle or Spot Height​​, by adding 100 feet for vertical error, then added another 100 feet of the risk of error.

 

Round the resultant sum to the next higher hundred foot level for the final figure. (A resultant figure shall not be rounded up to the next higher hundred foot level when it is an even multiple of 100).

 

MOUNTAINOUS AREA IN INDONESIA

Based on Sheet Indoavis ONC scale 1:1.000.000

  • North Sumatra (Indonesia), Malaysia and Singapore

  • East Sumatra, West Java

  • North Kalimantan (Indonesia), Brunei Darussalam and Malaysia

  • South Kalimantan (Indonesia)

  • Java and Bali (Indonesia)

  • Sulawesi (Indonesia)

  • Maluku and Halmareha (Indonesia)

  • Nusa Tenggara Timor-Kupang, Timor Leste

  • West Papua (Sorong, Manokwari, Kaimana)

  • East Papua (Wamena, Jayapura, Merauke)

EXAMPLE CHART

Examples of Indoavis SAC Scale 1:500.000 map in one quadrant of latitude longitude coordinates of lines per 30 Minutes


METHODS CALCULATION

 


PROVISION VALUE MAXIMUM ELEVATION FIGURE (MEF) ON INDOAVIS VFR (ONC) 1:1.000.000 CHART.

Calculation of the value of MEF (Maximum elevation figure) are published on the Indoavis ONC map scale 1:1,000,000 to Indonesia and surrounding areas. using NASA SRTM data with accuracy of 90 meters height.
All figures height using units of feet above MSL (mean sea level).

 

Below is a map issued by the MEF indoavis for area coverage maps ONC (Operation Navigation Chart) published