Go on the Internet and find the website for the airport at which the flight will be arriving. Almost all airports will have accurate information regarding arriving flights. From the main page, find the page giving flight status, arrival information, or a similar description. Once on the arrival information page, locate the Mexicana Airlines flight you are interested in to find the arrival time.
If you are still in need of more information, consider visiting a website that tracks flights. Use your preferred search engine and type in a phrase, such as "check flight status," then select the website of your choice. Most websites will likely ask for the flight number, airport, or similar information to help you find what you're looking for.
Contact the customer service department for the airline if you haven't found an accurate flight arrival time for your Mexicana Airlines flight. The customer service information can be found in the Resource section of this article.