Summary ATPL Theory - Instrumentation

INSTRUMENTATION
Summary / Notes

, Table of contents

Section 1 – Instrumentation Basics
Instrumentation General and Computers… ...................... 2
Air Data Instruments and Radio Altimeter ................................... 4
Gyroscopes… ................................................................................ 8
Magnetic Compasses ................................................................ 10
Inertial Navigation Systems… .............................................. 12


Section 2 – Instrumentation Systems
Display Systems… ..................................................................... 14
Flight Management Systems… ........................................... 18
Engine Instrumentation ........................................................... 18
Automatic Flight Control and Augmentation System ........... 22
Alerting Systems… .................................................................. 25
Recording and Maintenance Systems ....................................... 30
Data Communication Systems ..................................................31

, Chapter 1 – Instrumentation General and Computers
Instrument
-Sensor -> Processor -> Indicator

Instrument panels
-MIP L/R = Main instrument panel
-MIP C = Centre Main Instrument panel
-GSP = Glareshield
-PED = Pedestal
-OHP = Overhead Panel

ERP Eye Reference Position
-Avoid Parallax
-Reach all the buttons
-See the runway on landing

Display design
-Analogue (Circular / Straight)
-Digital
-Hybrid = Digital + Analogue
-Pictorial (Inside out / Outside in)
*Inside out = ATT, Outside in = TBI

Basic 6
-Artificial horizon
-Heading
-Airspeed
-Altitude
-Vertical speed
-Turn coordinator

Colour standardisation
-Red = Emergency
-Amber = Caution
-Green = Safe Status
-Blue = Temporary transit
-White = on / off status

Transmission systems
-Mechanical
-electro Mechanical
-Electronic / Digital

, Can Measure and Indicate angles
Synchro

-Converts mechanical angle to electrical signal (or can drive light needle)
-Transmit = Torque transmitter TX -> rotor = primary coil
-Receive = Torque Receiver TR -> stator primary coil
-Single rotor coil + 3 star wound stator coils
-heavy loads -> amplifier to drive servo -> Synchro-servo system
Can Only Measure angles
E-I Pickoff

-Very small angular/linear displacements
-2 soft iron cores, a fixed E-core and a moving I-core
-inner limb = E core fed with AC voltage -> Primary winding
-Outer limb = surrounded by opposite turning coils -> secondary winding
-Voltage -> Magnitude = displacement, Phase = direction

Larger displacement
-LVDT = Linear Variable Displacement Transformer
-RVDT = Rotary Variable Displacement Transformer

Computer
1. Central Processor Unit (CPU) -> microprocessors
2. Memory unit
3. Input / output units Peripherals
4. Communication Busses
-1 byte = 7 + 1 bits


Internal communication
-Data bus = Instructions
-Address bus = Location
-Control bus = Read / Write commands

External communication
-ARINC-429 = uni-directional bus for bitrate up to 100 kbps
-ARINC-629 = bi-directional bus for bitrate of 2 Mbps
Electro Mechanical Indicators
Software failure Definitions -Moving coil meter (fail -> off scale)
-Cat A = Catastrophic -A/D converter = Analogue -> Digital -Ratio meter
-Cat E = no safety effects -Transducer = convert energy forms -Synchro
-Servo (meter)
Processing

-Multitasking = 1 processor, more tasks at 1 (a1,b1,a2,b2,a3,b3)
-Multi processing = multiple processors doing separate tasks (a1,a2,a3 and b1,b2,b3)

Von Neuman Cycle = Fetch, Decode and Execute