Manitoba Airbrake Practice Exam

The brake application must be held for 1 minute when testing the air-loss rate of the brake system. This is because it allows enough time for any air that may be present in the system to escape and for an accurate measurement of the air-loss rate to be obtained. Holding the brake application for a shorter time, such as 30 seconds (option A) or 2 minutes (option C), may not fully purge all the air from the system and could result in an inaccurate reading. Holding the brake application for a longer time, such as 5 minutes (option D), is unnecessary and can waste time and resources. Therefore, the most efficient and accurate option is to hold the brake application for 1 minute.