The PS-525 displays altitude in feet and meters. The measuring units to be used are selected with the "UNITS" button. Press the button repeatedly until the desired measurement display is shown. Both feet and meters are displayed along with their vertical speed component.
The PS-525 tester displays altitudes in 1-foot increments up to 20,000 feet; 2-feet increments between 20,000 and 30,000 feet, and 5-feet increments above 30,000 feet; or in 1-meter increments if it is in the metric mode. The Vertical Speed Indication also increments by 25 feet or 10 meters. The VSI section will display an up or down arrow, depending on the direction of altitude change being sensed.
Accuracy will vary with altitude:
-1500 to 10,000 ft ..........+/- 5 ft
10,000 to 20,000 ft .........+/- 15ft
20,000 to 30,000 ft .........+/- 20ft
30,000 to 40,000 ft .........+/- 30ft
40,000 to 50,000ft ..........+/- 50ft (PS-525A version)
The vacuum pumps internal to the PS-525 tester will draw sufficient vacuum to go up to at least 35,000 feet (10,700 meters).
A PS-525A version is available, and goes up to 50,000 feet. This model uses stronger vacuum pumps and additional programming to extend the calibration values up to the higher altitudes and airspeeds.