Skip to content
View in the app

A better way to browse. Learn more.

The AVSIM Community

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.

THR elevation and Pressure Difference

Featured Replies

Hi,

 

On most LIDO charts, there tends to be a runway threshold, or TDZ, elevation shown.

For example, in EGLL, runway 09R it says: 79 / 3hPa (assumingly indicating runway threshold height)

So my question is, what does the Pressure after the elevation mean? Does this mean it Changes with 3ft every hPa change? So, let's say if you're entering the TDZ elevation in to your Head-up System, should you enter an elevation of 79ft Always, or correct it based on the Pressure difference?

 

Thanks.

 

 

 

Marcus Haraldsson

It's an info on how to convert between QFE and QNH. 

QNH = QFE + differential ( 3 hPa in your example )

Flying gliders since 1980

Flightsimming since 1992

AMD Ryzen 5600x, 32GB RAM, GPU Nvidia RTX 3060 Ti 8 GB, 1 TB and 500 GB nvme2 SSD drives, HP 27" 60Hz LED monitor @ 1920x1080, T16000, Hotas from old X52 Pro, Saitek Combat Rudder Pro (2010 model)

Archived

This topic is now archived and is closed to further replies.

Account

Navigation

Search

Search

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.