The Holding Pattern Calculator is a tool that assists pilots in determining both the correct holding pattern and entry method (Direct, Parallel or Teardrop) for an ATC assigned holding clearance. Its simple design provides excellent visualization of the aircraft heading in relation to the holding pattern.To use, simply touch the screen and rotate to set the holding pattern to the desired ATC assigned inbound leg.To aid in ease of use, both the track of the inbound and outbound legs are depicted. If the hold is non-standard (to the left) simply touch the "Non-Standard" switch to depict the correct pattern. Then select "Heading" and rotate the aircraft to the appropriate heading towards the fix. The image may also be locked to protect the settings from inadvertent touches by selecting the "Lock" button.The Holding Pattern Calculator is a useful and educational tool for pilots, student pilots, and aviation buffs, and is not intended to replace flight instruction.