Analog versus Digital Pitot Static Testers

Pitot Static Testers, or Air Data Test Sets, are pressure generators and measurement equipment used for testing and calibrating aircraft pitot-static systems. The testers are also useful in the troubleshooting of the autopilot, system connections, flight control systems, safety sensors, and pressure switches.

The name ‘Pitot Static’ comes from the Pitot and Static tubes on an aircraft that are connected to the aircraft and testing instrumentation. A Pitot Static Tester has the ability to leak test an aircraft’s Pitot-Static system and can generate the pressures or vacuums that are required to simulate the altitude and speed of the aircraft equipment to enable the calibration of the airspeed, altimeter, manifold pressure, rate of climb, and engine pressure ratio indicators on the aircraft.

There are two general types of Pitot Static Testers, analog and digital. The older analog testers contain analog instrumentation for the measurement functions and the newer generation of testers has updated digital indicators and a wider variety of functions for testing the high-tech aircraft of today.

Analog Pitot Static Testers

Analog Pitot Static Testers contain either two or three analog instruments (Altimeter, Airspeed or Vertical Speed) to perform the aircraft leak tests or instrument calibrations. They can have either hand pumps or internal electric pumps to generate the necessary pressures and vacuum for on-board testing and calibration.

The analog instrumentation in pitot-static testers are delicate mechanical devices which can be easily damaged or destroyed through improper use or handling. The analog instruments typically use mechanical bellows for the measurement and can require lengthy repairs to the mechanical structure if damaged and can be costly to maintain.

The reduced accuracy of the analog devices requires correction cards to be able to accurately determine the correct reading on the indicator. The accuracy limitations also do not allow the analog testers to certify units to the requirements of the RVSM (Reduced Vertical Separation Minima) regulations. When performing testing with the analog indicators, they must be tapped constantly to account for any sticking in the pointer movement.

Digital Pitot Static Testers

The continuous evolution of aircraft instrumentation due to technical advancements and regulatory changes has led to necessary improvements in the accuracy and number of operating functions required in the testing of the pitot-static systems.

Digital Pitot Static Testers contain newer digital instrumentation that provides a higher accuracy and better repeatability for the testing of pitot-static system functions. The digital testers are able to meet the high accuracy requirements of the RVSM specifications without any significant warm-up time.

The Digital Pitot Static Testers do not require correction cards for their instrumentation reducing technician calculations leading to higher confidence while operating the equipment.

Some Digital Pitot Static Testers contain automatic testing software that allows complete control over all testing functions which significantly reduces testing time for the aircraft. User test profiles can be programmed into the unit along with specific testing safety limits to protect both the aircraft and tester instrumentation during testing.

The Digital Pitot Static Testers are extremely easy to use and require very little training on their operation. Most systems can be run with just a few entries of the test functions on color-coded keypads to simulate the aircraft flying characteristics needed for the testing. Many digital testers also contain handheld remote units or they can be remotely controlled by a tablet or laptop with a wireless Bluetooth connection that provides versatility for the technician in the operation of the tester.

For additional information on the use and calibration of Analog or Digital Pitot Static Testers, contact e2b calibration.