Aircraft operation requires some sort of accurate airspeed and altitude information. Fueling these important flight parameters is the pitot-static system, a pressure-based system that provides data to flight instruments and air data systems.

Pitot static testing is an important part of aircraft inspection and maintenance because leaks, blockages, contamination and instrument inaccuracies can affect the reliability of this information.

This guide describes working of pitot-static system, what test results are evaluated by technicians, types of the pitot static test equipment and how to choose most appropriate one for a specific aircraft and other maintenance application.

What Is a Pitot-Static System?

The pitot-static system of an aircraft measures two main types of pressure: Pitot pressure (Pt) and Static pressure (Ps).

The pitot tube is positioned against the airflow and records total pressure, while static ports are placed to gauge ambient atmospheric pressure. The pressure inputs enable the calculation of key flight parameters on cockpit instruments and air data systems.

Three of the most recognizable instruments that rely on pitot-static data are:

• Airspeed Indicator - Measures the differential between pitot and static pressure; indicates airspeed.
• Altimeter – It adjusts your altitude by measuring static pressure.
• Vertical Speed Indicator (VSI) – Indicates climb and descent rate by measuring time derivative of static pressure.

Modern aircraft may also pass pitot-static pressure data to air data computers (ADCs) and to other integrated avionics systems.

If these pressure measurements are wrong, the derived values of airspeed, altitude or vertical-speed will be incorrect as well. So, it is important to focus on preserving the integrity of the entire system.

What Is Pitot Static Testing?

Pitot static testing is the process of simulating various pressures and vacuum conditions to an aircraft's pitot and static systems for different flight conditions while on the ground.

Technicians set test equipment to simulate desired parameters for altitude, airspeed, rate of climb or descent (and in applicable applications for the type of aircraft being tested) by utilizing an appropriately calibrated pitot static tester/air data test set connected to the system.

The known values created by the test equipment can then be compared with those of the aircraft's instruments or air data systems.

Technicians can identify problems by testing for:

• Pitot or static line leaks
• Blocked or contaminated ports
• Incorrect instrument readings
• Pressure-system integrity problems
• Air data system discrepancies
• Instrument or sensor needed to be readjusted recalibrated and repaired

The specific test methods and allowable tolerances are aircraft, system, applicable maintenance documentation and regulatory requirements.

Why Is Pitot Static Testing Important?

Pitot-static components are mounted in environments where moisture, dirt, debris, insects, ice, maintenance activity and normal component aging can interfere with their operation. Problems are not always readily apparent.

1. Detecting Leaks and Blockages

Even minor leaks can impact the pressure given to instruments on an aircraft.

Technicians use controlled pressures while testing and watch the system for indications of possible leaks. Pitot tubes and static ports can be checked for blockages or contamination.

Identifying these issues in the ground gives maintenance personnel time to take mitigation measures prior to affect aircraft operations.

2. Verifying Instrument Accuracy

The operation of aircraft instruments and pressure sensors can change over a period of time.

A calibrated air data test set has pressure values of which the technician should know with reference to. The resulting aircraft indications can then be compared with their associated allowable tolerances.

It can be used to test altimeters, airspeed indicators, vertical speed indicators as well as air data computers and related systems.

3. Supporting Regulatory Compliance

For U.S. citizens, flying under IFR, you must comply with FAA requirements for periodic testing and inspection of the altimeter and static-pressure systems.

Operators and maintenance organizations must always refer to the applicable regulations, aircraft maintenance manuals, approved data and operating requirements for the exact inspects, procedures, tolerances and intervals required on a given aircraft.

4. Supporting Reliable Maintenance

Pitot-static testing provides maintenance technicians with more scientific data rather than having to rely solely on the symptoms being provided by the pilot.

This helps isolate discrepancies, validate fixes and keep track of system operation.

How Does Pitot Static Testing Work?

Your procedure depends a lot on what aircraft and test equipment is being used. Technicians must always adhere to the applicable aircraft maintenance manual and test-equipment operating instructions, therefore.

A generic process can include stages like the following.

1. Preparation and Inspection

Before connecting test equipment, technicians check the condition of pitot tubes, static ports, hoses and fittings and adapters.

The technician also checks that a test set is appropriate for the aircraft and that it is still calibrated.

Correct adapters are particularly important. With differing pitot probe and static-port configurations across aircraft, technicians require suitable interfaces to provide a securely-formed, leak-proof connection without inflicting damage on aircraft assemblies.

2. Connecting the Test Equipment

You connect the pitot-static test set, through approved hoses, adapters and fittings to the required pitot and static pressure points.

The technician should confirm that every connection is tight and then pressure.

3. Simulating Flight Conditions

Controlled pitot and static pressures are generated for the selected flight parameters in order to validate the simulation over a test set.

Depending on the equipment, technicians should have the ability to manage and visualize:

• Altitude
• Airspeed
• Vertical speed or altitude rate
• Static pressure
• Pitot pressure
• Differential pressure
• Mach

These readings from the aircraft instruments or air data system are then compared to the test conditions.

4. Performing Leak Tests

If you set a pressure condition in a system that is monitored, and the system was to change its pressure beyond itself then this means there is an issue with integrity hence where they monitor.

Leak in hoses, fittings, instruments, plumbing, adapters and other components of the system cause an unexpected pressure loss.

5. Returning the System to Ambient Conditions

After testing is complete, the ambient conditions will need to be returned to previously approved procedure prior to disconnection of the equipment.

You want to change the pressure gradually because rapid changes can harm sensitive aircraft instruments or systems.

Pitot Static Test Equipment: What Should You Look For?

The choice of a pitot static test set is determined by what aircraft are being serviced, along with the tests to be performed.

Important factors include:

• Pressure and altitude range
• Accuracy
• Automated operation
• Pressure and vacuum source
• Remote operation
• Safety protection
• Adapters and accessories

Pitot Static Test Equipment Available from AvionTEq

AvionTEq is a provider of pitot-static testers and air data test sets for common aircraft maintenance applications. The criteria include the aircraft, required test parameters, operating band and accuracy requirements and maintenance environment.

ATEQ ADSE-743 Air Data Test Set

The ATEQ ADSE-743 automated, RVSM-capable pitot-static and air data test set easily performs flight-line testing on aircraft pressure instruments and air data systems. It is capable of testing altimeters, airspeed indicators, vertical speed indicators, air data computers and associated pitot–static systems.

It includes pressure and vacuum generation capabilities and can also be operated wirelessly, so technicians can operate testing from the cockpit or elsewhere around the aircraft. With a portable, weather-resistant configuration, it can be used in both hangar and flight-line applications.

GE/Druck ADTS-405F Air Data Test Set

The GE/Druck ADTS-405F is a digital automated air data test set for pitot-static and air data testing. It is used for pressure measurement and control to test aircraft instruments, components and systems. It has applications from an altimeter to an airspeed indicator, rate-of-climb indicator, Mach meter, and air data computer.

So, ADTS-405F is indeed proved and popular for flight-line applications, which offers Ps & Pt pressure generation of Pitot-static testing for aircraft.

Barfield DPS-500 Air Data Test Set

Another type of system for automated pitot-static and air data testing is the Barfield DPS-500. The DPS-500 has been designed as a compact standalone mobile test solution, merging an air data controller with integrated pressure/vacuum generation and remote control operations.

This setup can be handy when technicians need pitot-static tests with an instrument monitor from the cockpit.

Don't Overlook Pitot-Static Adapters and Accessories

The test set itself is only a part of a full pitot-static testing solution.

Technicians may also need:

• Pitot probe adapters
• Static port adapters
• Pressure hoses
• Adapter hoses
• Couplings and fittings
• Multi-port adapter kits
• Pitot/static covers
• Aircraft-specific interface accessories

Adapter choice should be on the aircraft in particular, probe, static-port layout, and sprayed upkeep method.

The right accessories create dependably connects and stops a leak in the connection from being reported as an issue with the airframe system.

Calibration of Pitot Static Test Equipment

A pitot-static test can only be as accurate as the equipment used to run it.

With time, sensors/to other metrics parts also can drift as compared to its desired functionality. Frequent calibration assures that the test set is still measuring within specification.

Calibration intervals for maintenance organizations should be developed and implemented according to OEM recommendations, internal quality requirements, agreed standards or regulatory requirements.

Calibration documentation and traceability also become considerations as the equipment is used for regulated work performed on aircraft.

Buying vs. Renting Pitot Static Test Equipment

A need to test doesn't always warrant the purchase of a test set.

For MROs, airlines, avionics shops and operators performing pitot-static testing frequently, that can make buying more reasonable. Having ownership ensures that the equipment can be accessed when needed and will be cost efficient when a high degree of utilization is possible.

In cases where the equipment will only be required infrequently, short-term maintenance, temporary capacity requirements, or aircraft-on-ground situations, then renting may indeed make more sense.

Another avenue for professional test capabilities available to organizations with limited capital-equipment budgets is certified refurbished equipment.

By evaluating expected use, length of time you need the range equipment, whether it is calibrated and certification status along with what other accessories are needed and overall price purchasing or borrowing rentals is a cinch.

Choosing the Right Pitot Static Testing Solution

When it comes to pitot-static testers, there is no one-size-fits-all.

Before making equipment choices, maintenance teams need the following:

• The aircraft and system being tested
• Required altitude and airspeed ranges
• Required pressure accuracy
• RVSM or other applicable requirements
• Number of pitot and static channels required
• Required adapters and accessories
• Need for automated or remote operation
• Calibration and certification requirements
• Flight-line versus bench or hangar use
• Expected frequency of use

Aligning the equipment and actual maintenance need can help prevent an elaborate system purchase—or later discovery that a chosen tester doesn't support the aircraft/procedure it is functionally selected to assess.

Final Thoughts

The pressure information is instrumental in deriving some of the key flight parameters on an aircraft, such as airspeed and altitude — hence the name Pitot-static system. So maintaining the accuracy and leak-free nature of these systems is a large part of aircraft maintenance.

During pitot static testing on the ground, technicians can check for leaks, test accuracy and troubleshoot any discrepancies — simulating real in-flight performance with the appropriate equipment as defined in applicable maintenance procedures.

AvionTEq is an aircraft maintenance equipment company specializing in pitot static test equipment sale and rental, as well as calibration, repair and technical support services for aviation maintenance organizations.

When purchasing an automated air data test set like the ATEQ ADSE-743, GE/Druck ADTS-405F, Barfield DPS-500 or a different pitot-static testing tool, selecting equipment matched to what the aircraft is and what needs to be truly tested are keys to accurate and efficient maintenance. Request a quote today at AvionTEq.