Instruments - Pitot/Static
Pitot/Static instrument/unit that we currently service:
- Air data system
- Airspeed indicators
- Altimeters
- Altimeters, encoding, blind
- Altimeters, servoed
- Mach limit warning switches
- VSI/IVSI
Altimetry
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.
Airspeed
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.