If passengers report a strange noise, visible ice, smoke, or an unusual wing condition, flight attendants may be asked to check the area through the window marked by the triangle.
Because these windows offer the best viewing angle, crew members can provide more accurate information to the pilots.
This helps the flight deck assess the situation and determine whether any action is necessary.
Why Pilots Find Them Useful
Pilots can also use the marked windows when conducting inspections from inside the aircraft.
For example, if there is concern about:
- Ice buildup
- Wing damage
- Flap position
- Mechanical abnormalities