On Flightradar24, a red plane icon typically indicates one of the following:
1. Most Common: An Alert or Squawk 7700 (Emergency)
This is the primary reason users see a red plane. It means the aircraft’s transponder is broadcasting a SQUAWK 7700 emergency code. This code can signify:
A technical failure (engine trouble, pressurization issues, etc.)
A medical emergency on board
A security issue
Any situation requiring priority handling from air traffic control.
2. Other Notable Squawk Codes (also often shown in red or with red highlights):
- SQUAWK 7600: Communication failure (radio failure). On Flightradar24, this is usually indicated with a blue plane icon, but some alerts may involve red.
- SQUAWK 7500: Hijacking or unlawful interference. This is a very rare but critical alert.
3. Ground-Based Alerts or Data Issues:
- Sometimes, if there’s a significant discrepancy in the aircraft’s tracked data (like a sudden altitude drop or irregular path), Flightradar24’s system may highlight it in red as an “alert” for users to note, even if it’s not an active 7700 squawk.
How to Confirm:
- Tap/Click on the red aircraft. The detailed information box will pop up.
- Look for the “Squawk” field. It will explicitly show 7700, 7600, or 7500 if one of those emergency/alert codes is active