Standard

Updated: 02/19/08

AVT 108 – Navigation Systems

Course Description:

Continues the study of avionics maintenance practices with emphasis on aircraft navigational systems. Topics include: bridges and monitors, synchros, gyros, and navigation systems.

  

Competency Areas:

Hours:

 

 

 

Bridges and Monitors

Class

5

Synchros

D. Lab

2

Gyros

P. Lab/O.B.I.

3

Navigation Systems

Credit

7

 

 

 

Prerequisite: AVT 104

Corequisite:

 

 

Course Guide

 

Competency

After completing this section, the student will:

Hours

Class

D. Lab

P. Lab/

O.B.I.

BRIDGES AND MONITORS        

6

2

6

DC bridges

Explain how voltage may be reversed in a sensing member of a DC bridge.

 

 

 

 

Discuss current flow in an unbalanced DC bridge.

 

 

 

 

Discuss current flow in a DC bridge under null condition.

 

 

 

AC bridges

Explain phase reversal as it applies to AC bridge circuits.

 

 

 

 

Discuss the use of capacitive and inductive elements in an AC bridge circuit and the resultant phase angles they produce in an unbalanced condition.

 

 

 

 

Give an example of the aircraft system application of an AC bridge using a variable capacitor.

 

 

 

Signal monitors

Discuss the operation of a signal presence monitor circuit.

 

 

 

 

Give the condition which causes a "flag" to appear in a signal monitor circuit.

 

 

 

Modulator/demodulator

Explain the operation of a 400 Hz modulator.

Explain the operation of a 400 Hz demodulator.

 

 

 

Summing points

Define summing point as it applies to avionics circuits.

 

 

 

 

Draw the symbol which represents a summing point with three inputs and one output.

 

 

 

SYNCHROS                                         

10

2

6

Vectors

Name the components of vector problems associated with aircraft flight.

 

 

 

 

Explain the resultant vectors of cross winds and speed.

 

 

 

 

Explain the resultant vectors of angular winds and speed.

 

 

 

Magnetic vectors

Explain the effect on a magnetic field when two "like" fields approach straight on and at various angles.

 

 

 

 

Explain the effect on a magnetic field when two "unlike" fields approach straight on and at various angles.

 

 

 

Two and three coil

Describe a two-coil electromagnetic field and explain how changes in coil voltage level affect the resultant vector.

 

 

 

 

Describe a three-coil electromagnetic field and explain how changes in coil voltage level affect the resultant vector.

 

 

 

Rotor and stator

Define the term rotor as it relates to synchros.

Define the term stator as it relates to synchros.

 

 

 

Abbreviations

State the meaning of the abbreviations TX and REC as they apply to synchro schematics.

 

 

 

Null

Explain phase reversal when a synchro rotor passes through null.

 

 

 

 

Determine direction of the field vector when presented with diagrams of various synchro rotor positions.

 

 

 

Application

Give examples of synchros use in aircraft avionics systems.

 

 

 

Differential

Explain the purpose of a differential synchro.

 

 

 

Resolver

Compare the output of a resolver synchro with that of a receiver synchro for any given degree of rotor movement.

 

 

 

Interpretation of diagrams

Recognize circle and coil schematic symbols for transmit, receive, differential, and resolver synchros.

 

 

 

Servo motors

Explain the operational similarities and differences between synchros and servo motors.

 

 

 

Servo application

Give examples of servos use in avionics systems.

 

 

 

Operational check

Operationally check avionics systems which use servos to control position.

 

 

 

GYROS                                                           

6

2

6

Precession

Explain the angle of precession of a spinning gyro when the axis is tilted.

 

 

 

Free

Compare the position of a spinning perfect free gyro as it is moved to different locations of the earth.

 

 

 

Application: horizon direction rate turn and slip

Give examples of avionics systems which make use of a gyro to provide attitude information.

 

 

 

Operation check

Operationally check indicators which use gyros to develop position information.

 

 

 

NAVIGATION SYSTEMS (Apply all tasks to each lesson.)                                

28

14

12

Compass

Inertial navigation system (INS) 

Automatic direction finder (ADF)

Instrument landing system (ILS)

Transponders

Distance measuring equipment (DME)

Marker beacon 

Radio altimeter

Air data systems (ADS)

Weather radar

Global Positioning Systems (GPS)

Loran navigation

Area navigation

Ground proximity warning system (GPWS)

VHF omni-range (VOR)

Remote Area Navigation Systems (RNAV)

Perform an operational check of each component of aircraft navigation systems.

 

Remove units and components of aircraft navigation systems.

 

Given entry from flightlog or work order, analyze a reported malfunction of aircraft navigation systems.

 

Use appropriate electronic measuring instruments to troubleshoot aircraft navigation systems to the unit, or component level where applicable, and isolate the defective item(s).

 

Replace units and components of aircraft navigation systems.

 

Document maintenance actions performed on aircraft navigation systems in accordance with local directives and Federal regulations.

 

Navigation principles, great circle routes, include enhanced GPWS and wind shear.

 

 

 

 

Suggested Resources

 

Books:

 

Bose, K. W. (1990). Aviation electronics (4th ed.). Casper, WY: IAP.

Eismin, T. K., et al. (1989). Aircraft electricity and electronics (4th ed.). New York: McGraw-Hill.

IAP, Inc. (1985). Basic electronics and radio installation. Casper, WY: Author.

IAP, Inc. (1987). Avionic fundamentals. Casper, WY: Author.

IAP, Inc. (1990). Aircraft inspection and maintenance records. Casper, WY: Author.

IAP, Inc. (1990). The best of AMJ maintenance tips. Casper, WY: Author.

Powell, J. (1990). Aircraft radio systems. Casper, WY: IAP.

 

Manuals:

 

Aircraft Maintenance Record (actual or simulated)

Aircraft Type Certificate Data Sheets

Manufacturers' Service Manuals