Pressure Measuring Instruments
What is known as gage pressure?
- Pressure measured from the existing atmospheric pressure
- Or the pressure above the existing atmospheric pressure
Page 724 PPT 1
What is “deviation error” in a compass?
Local magnetic disturbances from within the aircraft caused error in magnetic compasses
Page 748 PPT 3
List four instruments that may be operated by the pitot static system in an aircraft.
- Altimeter
- Airspeed indicator
- Rate of climb or vertical speed indicator
- Mach meter
Page 759-751 PPT 1 and 2
What are two main units of a synchro system?
Transmitter and a receiver (indicator)
Page 739 PPT 4
What does the white arc normally mean on an airspeed indicator?
Operating range with flaps extended
Page 783 PPT 6
What are four basic subsystems in an autopilot system?
- Command
- Error-sensing
- Correction
- Follow-up
Page 773-777 PPT 5
What is Absolute Pressure?
Pressure referenced from zero pressure or a vacuum
Page 724
The rotating magnet & compass card usually floats in _____________ to help dampen oscillations
Light Oil (Kerosene)
What is Static Air Pressure?
Pressure of the ambient air surrounding the aircraft.
Page 727
A bi-metallic strip thermometer measures temperature because the two strips of metals have different coefficients of____________________.
Expansion
Page 728
What can you do to instruments as an A&P mechanic (Name 3 things)?
- Replace
- Test
- External adjustments
- Repaint outside of the instrument
- New installations if done in accordance to a 337, STC, AD, Etc.
Page 786 PPT 6
(True or False )All autopilot systems are able to be over-ridden by the pilot!
TRUE
PPT 5
What required flight instrument uses both the “pitot” & “static” connection to get an indication?
Airspeed indicator
Page 762 PPT 1 and 2
What is a lubber line in a compass?
The reference line or wire in front of the compass card
Page 746 PPT 3
What is known as pitot pressure?
Ram air pressure which is affected by the forward speed of the aircraft
Page 759 PPT 1 and 2
What is generated in a thermocouple where there is an existing temperature difference between the “hot” and the “cold” junction?
A small current or voltage
Page 733 PPT 4
Why do we bond aircraft instruments?
Provides a path for return current from the components, and provides a low impedance path for grounding to reduce radio interference.
Page 785
The pilot is able to maneuver the aircraft when the autopilot is engaged by turning knobs or pressing buttons on the _____________.
Controller
Page 773
The pressure measured by an airspeed indicator is (absolute, differential, or gage) pressure.
Differential
Page 726
The compass is a completely self contained independent instrument. A&P maintenance these instruments consists of:
- Adjusting compensating screws
- Refilling kerosene (Servicing)
- Re-lamping
- Replacing the instrument
PPT 3
What is an Airspeed Indicator?
A flight instrument that measures the pressure differential between the ram air and static air.
Page 727
As the temperature sensed by a resistance bulb increases, the resistance of the bulb_____________. (increases, decreases)
Increases
Page 730
An aviation maintenance technician with an airframe rating _________ (is or is not) permitted to make a minor repair to an airspeed indicator.
Is not
Page 782
Autopilot servos are driven by signals supplied by the ____________.
Controller
Page 775
A Bourdon Tube is measured in (absolute, differential, or gage) pressure.
Gage
How is deviation error corrected or minimized in a wet magnetic compass?
By swinging the compass and adjusting compensating magnets
page 748 PPT 3
What is a manifold pressure gage?
A pressure gage that measures absolute pressure inside the induction system.
Page 727
Thermocouples used for measuring exhaust gas temperature are usually made of _____________ and _______________.
chromel, alumel
A red arc on a tachometer indicates a ________________ range.
Restricted Operating
Page 783
The two types of follow-up systems are the __________ and the ___________ systems.
Rate, Displacement
Page 777