Instrument Service

Our dedicated team of instrument technicians offer:

  • High level of competency
  • Quality dependable workmanship
  • No hassle warranty policy
  • A commitment to give you the best that is available

With an average of 18 years experience per technician, Pacific Avionics & Instruments is committed to maintaining our tradition of highest quality service to you. With this, your equipment will spend less time in the shop and more time in your aircraft.


Pilots will trust their instincts but for instrument related functions, accurate, reliable instrumentation is key to having the aircraft perform as it should.

Instruments provide information to the pilot which would otherwise be impossible. The required accuracy and dependability of this information cannot be underestimated. Reliable instruments for monitor engine and system performance particularly are an essential extension of the pilot, and trusting them is so important.

Pacific Avionics & Instruments understands this importance and is committed to ensuring that all instrumentation as well as system monitoring failures are minimized by restoring the original designed quality into instruments.


The idea of combining flight data into integrated flight instruments began half a century ago to help reduce pilot workload. Integrating situation display with flight command information assists the pilot in reaching the destination safely and efficiently.

Such data is further utilized by the Autopilot system.

  • Usually pitch and roll information is presented on the Attitude Indicator or Flight Director, while navigation or directional information is shown on the Course Indicator, often called the Horizontal or Navigation Situation Display.
  • Knowing which systems are function correctly is key, so monitoring circuits were introduced to drive flags and annunciators in these flight instruments, advising the pilot of invalid information or a malfunction.
  • What you see in these instruments is only a small part of the many associated transducers, gyros, computers and avionic boxes which drive them, and developing technology has reduced the weight and size of mechanical devices thus enabling even more features to be incorporated.
  • In spite of mechanical complexity, the fact that much of this equipment is still in service after typically 30 years is a testimony of the high standards. Although EFIS or electronic flight instruments is appealing, until the higher costs become economical traditional electro-mechanical instruments will remain in service for a long time yet, providing they are properly maintained.

With technicians on staff having well over 40 years in instrument repair, the benefit of nearly half a century of experience in properly maintaining electro-mechanical components can be your advantage. Don't let the consequences of mistakes through lack of experience cost you.


Friction and balance are critical for gyroscopic instruments to perform as they should.

Your gyro must:

  • be very clean
  • correctly assembled
  • have smooth bearings and a balanced rotor
  • be calibrated

Prior to any maintenance, your instrument is tested and evaluated, keeping in mind the reported fault. When we disassemble, clean and inspect the parts prior to assembly, you are assured that they meet their original quality.

What we do:

  • critical bearings are replaced with OEM supplied parts.
  • when your rotor requires overhaul it is completely rebuilt, balanced and run-in until it meets manufacturer's tolerances before it is installed.
  • OEM replacement parts are used.
  • assembled to the tolerances and specifications of the manufacturer.
  • hermetically sealed units are leak tested and gas filled.
  • the unit is calibrated to meet performance requirements of the OEM.

Then finally, a complete functional test is performed to ensure all functions are working correctly. Test results are documented for future reference and record keeping.

Always remember to care for your gyro as we do:

  • Never moving it around until the rotor has completely stopped running.
  • Never place it, no matter how carefully, on a hard surface.
  • Always keep your gyro packaged whenever it is not installed in the aircraft.
  • Ship your gyro in approved shipping containers.


Pitot/Static instrument/unit that we currently service:

  • Air data system
  • Airspeed indicators
  • Altimeters
  • Altimeters, encoding, blind
  • Altimeters, servoed
  • Mach limit warning switches

Regulations require that altimeters and altitude data transmitted to ground control must be accurate within known limits when flying in controlled airspace. To ensure this happens, all altimetry and ATC transponders must be inspected every 2 years.

The biennial inspection involves testing performance and accuracy of the altimeter, altitude encoder and transponder, then checking that data is being transmitted correctly from the aircraft.

A lot of things can go wrong with all of this and aside from mechanical aspects of the altimeter itself, the altitude reporting can display serious errors to Air Traffic Control if the data is faulty. The merits of accurate and dependable altimetry equipment can be easily recognized.

Pressures from the pitot and static ports are applied to the airspeed, altitude and rate of climb indicators. Testing for leaks or inspection for restrictions in the lines must be done during maintenance before dependable performance can be expected. Alternate static sources must also be checked, along with the drains and so forth.

With your static system its not always what you see so much as what you don't see, and what you don't see could be deadly!

Pacific Avionics & Instruments has been involved in the maintenance of pitot static instruments and related avionic equipment for over thirty years so why not let our experience be your assurance of reliable performance.


Movement through the air is the fundamental activity of an aircraft.

Knowledge of the correct speed, altitude and rate of climb is important to the pilot before optimum performance will be reached. With higher performance aircraft, airspeed is correlated to mach which is of course based on the sound barrier.

As speed increases, aerodynamics will sometimes adversely affect the static port pressure thus making it more difficult to measure altitude accurately. Static defect is corrected by the Air Data Computer or Static Error Correction device. Such equipment can be very complex requiring considerable maintenance activity.

Another device common in high performance aircraft is the Mach Limit Detector. This can be a pitot-static pressure switch, or a Maximum Limit pointer on the airspeed indicator, usually reading mach.

Knowledge and experience with equipment such as this is just one of the specialties at Pacific Avionics & Instruments We understand how to maintain this equipment so that it functions as it should. Do not risk having the performance of your aircraft compromised.

Vertical Speed

Knowledge of climb and descent rate is important for vertical navigation.

Usually this is obtained by measuring how quickly the static pressure changes; increasing gradually as we descend and decreasing as we climb. However, as with many things, this simple principle has become more complex when we instantly want the vertical rate, before any change of pressure can be noticed.

By balancing a set of pistons on springs which are sensitive to vertical acceleration, pressure can be applied to the Vertical Speed indicator diaphragm the moment deviation from level flight occurs. This device in effect responds to the inertia created by any change in the rate of climb or descent. After the change of vertical rate stabilizes to a steady vertical rate, the pistons normalize and indication then depends on changes in static pressure.

Servo driven altimeters are an alternative method of sensitive vertical rate information to the pilot, as are Air Data Computers.

Why not entrust your sensitive instruments and avionics to those of us at Pacific Avionics & Instruments who have been maintaining this equipment successfully for nearly half a century? The consequences of mistakes through lack of experience can be very costly.

Rotor Balancing

Why is rotor balancing critical?

Due to the required weight of rotors spinning at very high speeds for the necessary inertia, the technology of rotor bearings is taxed to the limit. Rotor bearings must be perfectly aligned and preloaded to eliminate any looseness or ball clatter when running.

Technology is also highly developed to ensure lubrication occurs progressively over the full life expectancy. If such an expected life is to be achieved, then vibration must be eliminated (or reduced to acceptable levels).

These limits are determined and specified by the gyro manufacturer during development and without knowing if the vibration is below the design maximum allowable, we cannot guarantee the bearing will survive.

Also, during the process of balancing the rotor, the technician can confirm whether or not the bearings have been installed and preloaded correctly. If there are any problems with the bearings at all, the balancing machine will help us to identify the cause.

Important Details to Remember

Only with correctly installed bearings, properly preloaded, everything balanced and then run in, will the rotor perform as it should and display that smooth sweet sound to indicate that it is ready to be installed in its next higher assembly.