At what altitude does the PM call out "transition altitude"?

The correct altitude for the PM to call out "transition altitude" is FL180. This is a standardized altitude where aircraft change from using altimeter settings based on local air pressure to using standard pressure settings (29.92 inches of mercury).

At FL180, the transition between en route and approach operations and between the altimeter setting methods is clearly defined, allowing pilots to maintain uniformity and safety in altitude reporting. As the aircraft climbs through this altitude, pilots switch their altimeters to the standard pressure setting to avoid discrepancies in altitude reporting between different aircraft, which is critical in maintaining safe vertical separation in controlled airspace.

Understanding the transition altitude is essential for effective flight operations, as it aids in consistent communication and reduces the likelihood of altitude errors between climbing and descending aircraft in a busy airspace.