Exam Revision Flashcards
(341 cards)
1
Q
What is a wire and what is it’s purpose?
A
- Single insulated electrical conductor
- Distributes power
2
Q
What is meant when referring to a wires shielding? What does it do?
A
Generally copper shielding material prevents electromagnetic interference (EMI) between sensitive circuits
3
Q
What is a cable?
A
Two or more insulated electrical wire conductors
4
Q
What is the ‘norm’ for a bundle common of wires?
A
May be twisted together or contained in common outer covering of insulation or shielding material, over which can be additional outer insulating jacket
5
Q
What does a co-axial cable do?
A
Supply RF energy signals from antenna to avionics systems
6
Q
What are some systems that use the co-axial cable?
A
VHF COMMS, LRRA, DME, ATC, VHF Nav
7
Q
Is co-axial cable one way or two way signal?
A
Two way signal
8
Q
What does a thermocouple wire do?
A
Constructed of special materials required for use in EGT systems
9
Q
Why are cables twisted?
A
To prevent extraneous magnetic field interference between sensitive circuits or systems
10
Q
Why are there multistranded wires?
A
If one wire breaks, it is still connected
11
Q
Where is tin coated conducted wire not used? Why?
A
- Fuel circuits due to fuel corroding wire
- In areas where it can be exposed to operations and elevated temperatures, corrodes.
12
Q
What sort of conductors are used in conditions of elevated temperatures?
A
Nickel plated copper conductors
13
Q
What is the advantage of using multistranded aluminium conductor wires?
A
Saves weight
14
Q
Where would you not use aluminium conductor wires?
A
Areas where there is high vibration
15
Q
Where are aluminium conductor wires usually used?
A
Within the pressurised fuselage
16
Q
What sort of wiring insulation material must be used?
A
Must be such that no toxic fumes evolve in event of wire failure
17
Q
What is Flemmings Law?
A
Cancels out magnetic field by having two wires with return path back to source
18
Q
Why don’t companies ‘hot stamp’ wires/cables anymore?
A
Hot stamping can potentially damage wires/cables
19
Q
How do Boeing number stamp their wires?
A
- Specific bundle ID number (e.g. W242)
- Specific sequential number (e.g. 001 to 999)
- Gauge of wire (e.g. 22 or 20) W242-001-22
20
Q
What sort of system does Airbus use to number stamp its wires?
A
Air transport Association (ATA) system
21
Q
How does Airbus number it’s wires?
A
Unique code dedicated to different system (i.e. 23 = comms, 10=HF/VHF) followed by sequential number of wire followed by gauge. 2310-899-22
22
Q
What questions should be asked before installing a wire?
A
- What wire gauge
- Is it in a SWAMP area (severe wind and moisture problem)
- Is it subject to corrosion (fuel or hydraulics)
- Does need additional insulation
- Does it need to be shielded temperature range exposed to (-65 to 150)
23
Q
What should be done with regards to installing bundled wires?
A
- Prevent electrical interference with other bundles
- Not interfere with any moving control systems
- Have at least 12 mm clearance from any hydraulic line/pipe
- Clipped to secure bundles to airframe or power plant to establish clearance
- Installed and protected in metal conduits or fibre glass raceways to prevent chaffing
- Sleeving to prevent chaffing from vibration
- Wires routed so bends dont exceed minimum bend radius of wire (10x outside diameter of largest wire/cable in bundle)
24
Q
How are wires/cables etched with id number?
A
UV laser etching or plastic sleeving that are indelibly
25
Why is polyvinal chloride insulation (PVC) not used on wires/cables?
Releases toxic fumes when wire broke
26
What is a disadvantage of using kaplon wiring/cable insulation?
Can exhibit circumferential cracking when acceptable bend radii exceeded.
27
What are good types of insulators for wires/cables?
* PTFE
* Kapton
* ETFE
28
What is the first thing you should check before replacing a wire?
The wire diagram manual to find preferred wire/cable type
29
What would you need to do if you wanted to use a wire not in the WDM?
Seek approval from CASR 21.009 and/or CASR 21.437 CASA delegate
30
When replacing a wire, what should you do with regards to the WDM?
1. Check the wire list (contains info on every wire used in the aircaft as well as manufactures preferred type of wire/cable)
2. If wire/cable isn't on wire list, check the Alternate wires/cables section
3. If not on that list, need to get CASR 21.009 and/or CASR 21.437 approval
31
What must be checked with the connectors/receptacles?
That the pins & sockets are the correct size
32
Why are solder connections not used any more?
It can run down the wire and lead to wire losing flexibility
33
What is grounding?
Terminations that require connection to airframe
34
What considerations are needed for clamping?
* wire bundles properly supporte
* properly sized and correct material type
* spaced correctly for environement
* mounted correctly
35
What is routing?
Adds wires needed to connect components
36
Why is routing important?
* Eliminates chaffing
* Makes sure correctly located with respect to proximity to fluid lines
* Correct bend radii
* Protection against cargo damage and/or maintenance damage
* Adequate access for repair/maintenance
37
What must be placed inside metallic conduit?
Teflon sleeving over wires
38
Why is an AC (alternating current) preffered to a DC (direct current) system?
* It is simpler, cheaper and more efficient than DC generator to produce same voltage level
* permits the use of transformers to change voltage (either higher or lower)
* Frequency of oscillation (more efficient)
39
What is the CSD?
* Constant Speed Drive
* Hydromechanically operated gear transmission system that couples engines accessory gearbox to Generator
40
What does the CSD do?
* converts variable engine speed of accessory gear box to constant speed for driven generator to produce AC electrical power at constant frequency
41
How does the CSD maintain constant speed?
It has a governor to maintain approx 6000rpm
42
In the event of CSD/generator malfunction, what can pilots do?
Disconnect generator drive from engine accessory gear box via switch
43
After disconnection, when can we reconnect CSD/Generator?
Only on the ground
44
How can we monitor the 'health' of the CSD?
Low Press (pressure) and Temp indicator warnings in the cockpit
45
What sort of power does the generator provide?
115 +/- 3 Volts
400 +/- 5 Hz
46
Why do we use 400Hz?
* Chose for weight saving purposes.
* frequencies above 400Hz cause skin effects (current flow not evenly distributed)
47
How is the generator cooled?
Cooling supplied to Generator by ducting from engine fan air
48
What are the advantages of three phase vs single phase in ac generation systems?
* Can be operated at slower speeds to produce same power
* Peak voltages seperated by 120 degrees and not 360 = steadier power output
49
In the generator, what is the 'neutral' point connected to?
Connected to the ground
50
What is the volt ampere rating?
Max amount of energy (current) that generator can supply to demands of electrical and avionic services
51
How much volt ampere can generator supply?
45kVA, note the maximum load is 50kVA however this is never demanded from generator.
52
What is the purpose of the Generator Control Unit (GCU)?
* Provides automatic operation of control functions of each generator system
* provides signal to 'trip' the generator control breaker (GB) (trip = open circuit/take off line)
* regulates generators voltage and limits amplitute of generators phase voltage under fault conditions
53
What does the GCU protect the generator from?
* Overvoltage (127-133 volts- gb trips)
* Undervoltage (within 5-9 s of dropping below 93-103 volts, gb trips)
* Overfrequency (425-435Hz, gb trips)
* Underfrequency (360-370, gb trips)
* Differential feeder faults (difference between phases exceeds 20 amps, gb breaks)
* Over current (if total load on Generator exceeds 170-175amps, after time delay, GB trips)
54
What does "BUS OFF" indicate?
When either GEN or APU GEN (aux power unit) is not supplying the GEN BUS
55
What does GEN OFF BUS light indicate?
When GEN is not supplying its GEN BUS
56
What does TRANSFER BUS OFF indicate?
When transfer bus is not powered by GEN BUS
57
What is a relay?
Electromagnetically operated mechanical switch, when current applied to coil, arm moves and completes circuit.
58
What happens if any generator fails?
* That generators bus won't be supplied with 115volts
* APU can be started and supply that GEN BUS
59
Why do we have automatic bus transfer system?
It increases electrical power reliability, i.e quicker response time in supplying failed bus
60
Why does APU not have a CSD?
After completion of APUs starting cycle, drives generator at constant speed of approx 6000rpm
61
What is the main difference between 747 and 737 power generation systems?
Very similar, it has four 115V ac 3 phase, 400Hz except it can supply up to 90kVA loads
62
How many integrated drives and generators (IDG's does 747 have and how are they connected?
4 and in parallel
63
How many engine driven generators does an A380 and what is their output?
4 and 150kVA each
64
How many APU generators does an A380 have? And with what output capability?
Two and 150kVA
65
While the A380 power system is fully computerised, how does 737 and 747 GCU control their generating systems?
Transistor circuits
66
How many ac generators does a 787 have?
2 per engine 250kVA each
2 on APU 250kVA each
67
What can static electricity interfere with?
HF and Nav (ADF in particular)
68
What does bonding do?
* Ensures aircraft is of same electrical potential
* Metal parts electrically connecte to conductive structure
* Non metal parts bonded to ac structure via conductive return path (conductive paint, aluminium strips, stainless steel mesh)
69
What in the aircraft is bonded?
* All control surfaces
* Avionics racks
* Circuit ground terminals
* Radio/NAV antenna
* Galley
* Fuel lines
* Hydraulic lines
70
What can inproper bonding lead to?
* Radio/comms interference
* injury
71
What is the purpose of bonding?
* Protect from lightning strikes
* Current return paths for electrical/avionic circuits
* prevent development of RF potentials
* protect from electric shock
* prevent interference with radio
* prevent accumulation of static charges
72
What is the basic bonding process?
1. Clear area of paint/con-conductive finishes and corrosion
2. Protect area using alodine
3. Establish bond
4. Measure bonding resistance
5. Surface around the bond re-painted
73
What is the purpose of the HF Comm system?
* Provide comms link between flight crew and ground
* HF Data Links (HFDL)
74
At what hert does HF comm system transmit/receive?
2-30 MHz
75
What is HFDL?
* HF Data Links
* Worldwide comms between ac and ground
* works over north pole
* Lower cost than SATCOM
76
What do a HF Comm system consist of?
* Receiver transmitter (RT)
* Antenna
* Antenna Coupler
* Control Panel
* Remote Electronic Unit
77
What does the RT do?
* Provides transmit signal and power to antenna at selected frequency
* Processes received signal from signal at selected frequency
* provides AM, Single Side Band Mods, Voice and Data Comms
78
What does antenna do?
* Radiate transmitted RF energy it receives from RT
* Receives RF energy directed to ac from ground
79
What determines the efficiency of the antenna?
Length and/or postion of antenna
80
What sort of aircraft is a fixed wire antenna attached to?
Slower turbo prop and jets
Piston ac
81
What are the advantages of notch/shunt antenna over fixed wire?
* It's flush and has no impact on structure leading toreduced drag and less weight
* Doesn't require lightning protection
82
Where is the antenna coupler located?
Vertical Stabiliser
83
What does the antenna coupler do?
Matche antenna impedance to RT over HF range
84
What does the Antenna coupler tune the antenna to?
50 ohms
85
What does the control pannel consist of?
* On/Off switch
* Mode Selection (USB/LSB or AM)
* Frequency selection (1 and 10 kHz)
* RF sensivity
86
What is the signal/noise ratio?
Ratio between magnitude of signal to background noise
87
Which is better, high or low signal to noise ratio?
High
a low s/n has hiss and static
88
Which is more efficient, AM or USB/LSB and why?
* USB/LSB, they use less power to carry modulating signal
* Provides greater range (uses all transmitter power to convey voice info)
* Clearer speech
89
What does Amplitude modulation consist of?
Carrier frequency and corresponding side band frequencies
90
What does Upper side band consist of?
Carrier frequency plus modulating frequency (FC + FM)
91
What does Lower side band consist of?
Carrier frequency minus modulated frequency (FC-FM)
92
What does the REU do?
Process all radio audio signal from each crew station
93
How is the HF propagated?
1. HF Signal leaves antenna and remains near surface (ground wave)
2. Sky wave leave antenna and goes up into ionosphere, then reflects signal back to certain frequencies (skip)
94
Define Maximum usable frequency?
* Highest transmitted frequency that is reflecte back to earth
* Signal absorbed the least
* gives greatest reflection back from ionosphere
95
Should you use HF when refuelling?
No
96
What frequency should you use during day and night?
10-30 during day
2-10 during night
97
How does VHF operate?
Uses line of sight (no ionosphere propagation)
98
What frequency range does VHF go from?
118.000 to 136.975 kHz
99
What sort of spacing is there between channels?
25kHz spacing = 760 channels
Some parts of Europe and US, 12.5kHz spacing 1520 channels
100
How does VHF transmits its radio waves?
AM techniques
101
What are some advantages of VHF over HF?
* Offers least amount of interchanel interference
* Smaller antenna
* more efficient power trasnmitted from RT to ground receiver
102
What sort of antenna is both HF and VHF?
Omnidirectional
103
What range does VHF have?
120nm @ 10000 feet to 245nm @ 40000feet
104
Where are VHF Comm 1 and VHF Com 2 located?
VHF Comm 1 on top (incase of belly landing)
VHF Comm 2 on belly
105
What is VHF Comm 3 normally dedicated to?
ACARS (Aircraft Communication Addressing and Reporting System)
106
What is ACARS?
Simple digital messages to and from aircraft
Out/Off/On/In messages
107
What does the following mean?
ADO733/0745 EA 0836 SYD
Out ADO0733
Off 0745
ETA for Sydney 0836
108
How does HF data link differ from ACARS?
* Provides coverage when out of VHF Range (i.e. oceanic and polar routes)
* Transmitted to ground via SATCOM (or other satellite)
109
How many volts are provided to DC system?
28 volts DC
110
How is the 28 dc volts provided to DC power systems?
* 3 transformer rectifier units (TRU)
* Battery (nickel cadmium)
* Battery charger
* Cockpit control and indicator panels
111
What does the TRU do?
Supplied with 115 Vac and converts it to 28 Vdc
112
What is the advantage of 3 phase ac then rectifying and filtering?
* Much shorter dc wave with less ripple voltage
* Output of TRU is regulated and ensures constant voltage
113
What is elements is the battery made up of?
Nickel and Cadmium (Ni Cd)
114
What is the amp hour capacity on the average Ni Cd battery?
36 amp hour capacity
115
What are the advantages of Ni Cd batteries over Lead acid type?
* Better weight to energy ratio (NiCd lighter)
* Can supply higher current demand and withstand higher charges
* Has Longer life
* more robust
116
What are the disadvantages of the Ni-Cd battery? And what is done to assist?
* Temperature sensitive during charging, so is fitted with a temperature monitoring device that goes off above 58 degrees
117
Which is the negative and which is the positive element in a Ni-Cd battery?
Ni = positive
Cd = Negative
118
What is 'charging' of battery?
Conversion of electrical energy into stored chemical energy
119
What will a 25 ampere hour battery deliver?
25 ampere for a minimum of 1 hour
120
What is the service life of a Ni-Cd battery?
250 hours
121
What is supplied by the battery power?
* Ground service ops (lighting) during refuelling
* Starting of the APU
* Last resource of electrical energy in event of total power failure
122
What is electric load analysis?
* Determines loads battery must supply
* TIme battery endurance under emergency conditions is approx 40 mins
123
How is the battery charged?
Supplied from 115 Vac Ground Service Bus (GSB)
Sensing circuitry determines charge state and provides rapid charge followed by pulsing charge
124
When does the charge current cease? And why doesn't it continue to charge?
When battery is considered by circuitry to be charged. Doesn't continue to charge because otherwise cell voltage will rise with charging process and charge current requirements will fall
125
What do TRU1 and TRU2 provide power to?
BUS1 and DC BUS 2
126
Are TRU1 and TRU2 in parallel?
Yes
127
What does TRU3 do?
* Is a back up for either TRU1 or TRU2 in event of failure (provided BUS TRANSFER is in AUTO)
* Main function to supply power to 28 Vdc battery bus (providing BAT SW ON)
128
What is the alternate supply when 115V Main AC BUS 2 not powered?
Hot Battery Bus
129
What happens when battery switch is selected to on?
Guarded switch goes down
28 Vdc batt bus normally supplied by TRU3 if 115 V Main AC bus 2 is powered
130
What happens when battery switch is off?
* Guard is lifted
* No power is supplied unless Standby Power is in 'BAT' position
* Prevents ignition of fumes
131
What is it called when the battery is unservicable?
Total Discharge State
132
Where is the Auxiliary Power Unit started from?
AC Battery on ground
133
How much AC power via generator does Auxiliary Power Unit supply on ground and in air?
60kVA on ground and 50kVA in air
134
What is Auxiliary power Unit powered directly from?
28 Vdc Hot Battery Bus
135
How is the Auxilary power unit started?
1. Battery charger disconnected from battery bia APU start interlock relay
2. This realy prevent battery charger supplying any dc current via 28 Vdc hot battery bus for APU start
136
In the event of an emergency, what systems powered by the battery?
* VHF Com 1
* Engine and APU Fire detectors and extinguishers
* STBY FLT Instruments (ALT, IVSI and ADI)
* STBY RUDDER FLT Control Hyd Valves
* APU Starting
* No1 IRS
* Engine Fuel Shut off an Cross feed valves
* Engine Wing anti ice
* Landing gear indicator and aural warning
* Engine ignition system via ac standing bus
137
What is the purpose of the FDR?
* To collect data that helps investigators in event of crash
* Assist engineering with engine trend monitoring (vibrations or EGT monitoring)
* picks up crew erros, external events or AC failures
138
What were the original FDRs like?
* Inconel steel foil (nickel cobult alloy)
* could only record 5 parameters
139
How many parameters coud the original FDR record and what are they?
* 5
1. Heading
2. Airspeed
3. Altitude
4. Vertical acceleration
5. Time
140
How did the original flight data recorders, record their data?
Individual steel pens would inscribe on metal foil
141
How many hours would the original FDR record for?
200 hours, after that they would need to be 'flipped'
142
What were the main problems with the foil fdr?
* Impact withstand low, 100G
* Fire survivability low
* Foil jams
* Foil tears
* Loss of data when end of foil reached
143
After foil FDR, what was the next generation of FDR like?
Magnetic recording tape
144
After the foil FDR, how many parameters did CASA mandate?
20 new parameters
145
How long did magnetic recording FDR record for?
25 hours
146
What survivability does magnetic FDR have?
* Fire survivability of 1000 degrees for 30 mins
* Impact tolerance 1000G
147
How many parameters could magnetic FDR record?
300
148
Following an accident, where does the data from FDR go to?
ATSB
149
What are the new FDRs like?
* Use memory chips
* Record \>200 hours depending on digital flight data aquisition unit (DFDAU) to which FDR is interfaced
150
What does the FDR consist of?
* DFDR
* DFDAU, collection point for ALL parameters
151
What parameters are recorded?
* ON/OFF
* UP/DOWN
* Auto pilot
* Engaged/Disengaged
Plus many more
152
How are parameters recorded?
* Recorded as analog, digital or logic signal
153
How are vertical, longitudinal and lateral acceleration sensed?
3 axis accelerometer
154
What does the DFDAU do?
Passes data to DFDR in digital format
155
What is the time fram for recording data in DFDR?
Frame = 4 seconds
Divided into 4 subframes each 1 second long
Data is presented to DFDR at 64 words per second (subframe) from DFDAU
64 words per subframe and 12 bit per word
156
CAO 103.19 Appendix 1 states that vertical acceleration must be recorded at interval of 0.125 s, how many times is this recorded per second?
1 / 0.125 = 8
Recorded 8 times per second
157
CAO 103.19 Appendix 1 states the squat switch must be recorded at interval of 0.5 seconds, how many times is it recored per second?
1 / 0.5 = 2
Recorded 2 times per second
158
During the harvard bi-phase, if remains at +5V or -5V for the whole bit cell, what is this said to be?
a 0
159
During the hardvard bi phase, if fluctuates from -5V to +5 V, what is this said to be?
A 1
160
For the VA with 0.125s and 8 times per second recording, what is the best sampling method per 64 word/Second?
2, 10, 18, 26, 34, 42, 50, 58 and then recommence at 2 in SB2
161
What is the survivability of the CVR?
Same as the FDR
162
How long doe CVR record for?
30 mins of continuous recording, however the SSCVR records last 2 hours of flight before memory is over written
163
What does the CVR actually record?
Pilot and Co-pilot audio
Observers audio
Area microphone
164
When can the erase switch be used?
When no safety events have occured in last 30 mins when AC on ground
165
How do you erase CVR?
Erase switch pressed for 2 seconds when on ground and park brake is set
166
When is the FDR reasonableness check done?
Ever 2500 flight hours
167
What is involved in a flight reasonableness check?
Tape assessed to make sure mandatory parameters plus the others are being recorded properly
168
What is mandatory to be attached to the blackbox?
Underwater locator beacon
169
What does the underwater locator beacon transmit at and how long does it last?
37.5kHZ and last for 30 days after activation
170
What happens if the FDR fails on ground?
Plane cannot take off unless at an airport when maintenance of FDR cannot be done
171
Why do we use logic circuits?
Because flight crew operations manual (FCOM0 use logic gates to show how complex systems function
172
With logic gates, what is a low and what is a high?
Low = 0
High = 1
173
With a low (0) what are the normal outputs?
False
Low
Off
Open
Open (switch not to ground)
Down
174
With a high (1) what are the normal responses?
True
High
On
Closed
Close(switch to ground)
Up
175
Describe the AND gate
Output is true when both inputs are true (1) otherwise it is false
X=AxB
176
What picture represents the AND gate
Big D
177
# Fill in the blanks for this AND gate
Input 1 Input2 OUTPUT
0 0 ?
0 1 ?
1 0 ?
1 1 ?
0
0
0
1
178
Describe an OR gate
Output is true (1) if either or both of inputs are true.
If both inputs are false, then output is false
X=A+B
179
What picture represents the OR gate?
Big arrow
180
Complete this OR gate
In In Out
0 0 ?
0 1 ?
1 0 ?
1 1 ?
0
1
1
1
181
Describe an Exclusive Or (XOR) gate
Output is true if either but not both inputs are true. Output is false if both are false or both are true
182
What picture represents the XOR gate
Line before a big arrow
183
Complete this XOR gate
IN IN OUT
0 0 ?
0 1 ?
1 0 ?
1 1 ?
0
1
1
0
184
Describe the inverter gate (NOT gate)
One input and one output
Output reverse logic state of input
185
What picture represents the NOT gate?
Triangle with a ball on its tip
186
Finish this NOT gate
IN OUT
1 ?
0 ?
0
1
187
Describe a NAND (not and) gate?
Output is false if both inputs are true, otherwise it is true
188
What picture represents a NAND gate
big D with a circle
189
Finish this NAND logic gate
IN IN OUT
0 0 ?
0 1 ?
1 0 ?
1 1 ?
1
1
1
0
190
Describe a NOR (not or) gate
Output is true if both inputs are false, otherwise output is false
191
What picture represents NOR gate?
Arrow with a circle on point
192
Complete this NOR gate
IN IN OUT
0 0 ?
0 1 ?
1 0 ?
1 1 ?
1
0
0
0
193
What are the advantages of relay switch?
Can switch AC and DC
Can switch high voltages
Large currents
Many circuits simultaneously
Can use relatively low currents to operate relay coil
194
What are the disadvantages of relay?
HEavier
Can't switch rapidly
COnsumes more power
195
An AND gate is connected in what? Series or parallel?
Series
196
A OR gate is connected in what? Series or parallel
Parallel
197
A triangle represents what on logic circuit?
Relay
198
What does Ground Based Primary Surveillance Radar (PSR) determine?
Range and azimuth
199
What frequency is the PSR?
2.7-2.9 GHz
200
What is the down side of PSR?
Uses a lot of RF energy
201
What does the secondary surveillance radar (SSR) do?
Assignes 4 figure 'skin' code.
AC can 'squwark' this code either manually or through automatic airborn system
202
How does the ATC get squwark code?
1. From the ground, P1 and P3 pulse trasmitted from rotating SSR towards AC at 1030MHz
2. AC replies at 1090MHz
203
What does the first set of P1 and P3 pulses do and what mode is this??
Requests IDENT code
MODE A
204
What is the second set of P1 and P3 pulse requesting and what mode is this?
Requesting altitude
Mode C
205
What is the third pulse and when does it occur?
P2 and 2 useconds after P1 pulse
206
What antenna does P2 pulse come from?
Omnidirectional antenna
207
What antenna does the P1 and P3 pulse come from?
Directional antenna
208
What is the purpose of the P2 pulse?
Transmitted by SSR rotating antenna at 1030 MHz. Surpresses RF energy from interferring with ATC P1 and P3
209
What is a side lobe?
Unwanted SSR RF energy
210
By how much does the P2 pulse supress side lobes by?
-10db
211
What is the altitude send as in Mode S transponder
1013 millibars in 100 ft increments
From -1000 feet to +126700 feet
212
How does the Mode S transponder send IDENT?
F1 and F2 pulses transmitted at 1090 MHz
213
What does Mode A transmit?
IDENT info
214
What does Mode C transmit?
IDENT and ALT
215
What does ALT SOURCE do?
Determines if DADC 1 or 2 is source of altitude data
216
Where does the mode S code come from?
ICAO
217
What is the break up of the Mode S code?
First 6-8 bits country of origin code
Remaining 18 bits unique S mode address
218
What is the range of Mode S?
100nm at 10000 feet
200nm at 30000 feet
219
What does the Air Traffic Control Radar Beacon System (ATCRBS) use to detect location of aircraft with respect to ground station?
PSR. The SSR then interogates AC for IDENT and ALT
220
Is the LRRA pulse operated and what does it detect?
No, not a radar, is frequency modulated
Detects height AGL
221
What happens if P1 = P2?
It will give an error. Means it has picked up suppression
222
Where does airborn weather radar detect weather conditions?
Ahead of aircraft
223
What does weather radar detect?
Weather that has precipitation in it (rain, thunderstorms etc)
224
What does weather radar have difficulty in picking up?
Ice and hail, (dry precipitation)
225
What does weather radar consist of?
Radome
Antenna
Wave guide
Radar RT
Plan Position Indicator (PPI)
226
What is a radome?
Kevlar/fibre glass honey combe structure which protects radr antenna
227
What does it mean when a radome is said to be transmissive?
Means how efficiently it permits RF energy to pass through without weakening the RF energy
228
What are the two types of weather antennas?
Parabolic
Phased Array (flat plate)
229
What do the two antennas both have?
Drive mechanism
230
What do weather radar antennas do with RF energy?
Direct RF energy toward target (storm area)
231
Where are the weather antennas and drive mechanism located?
Forward bulkhead
232
What scan arc does the weather radar detect?
180 degrees
233
What is the wave guide?
Hollow metal tube where the RF energy is transmitted by RT and passes through to the antenna
234
What are the downfalls of the wave guide?
Can have moisture problems
235
How do you overcome the moisture problems in the wave guide?
Application of cabin air pressure
236
How much RF energy does the RTU produce/transmit?
9.333 GHz
237
What is the range of the weather radar RTU?
Approx 300nm
238
What does the weather RTU do?
Process and amplifies analog returning RF energy to produce digital data on the range, bearing and target info
239
Where is the weather displayed after being detected?
on Plan Position Indicator (PPI) or EFIS
240
Which is better, parabolic or phases array antenna?
Phased array antenna
241
Why is the parabolic antenna worse than then phased array?
Parabolic produces side lobes
Parabolic uses more power (60 kw compared to 600 mW)
242
Why is the phased array antenna more accurate?
* Has slots over surface area
* These slots ensure RF energy are efficiently radiated infront of the aircraft
* Results in fewer side lobes and more RF energy to detect weather
243
How much better is the phased array antenna than the parabolic antenna?
approx 50%
244
What is the beam width of phased array antenna?
3 degrees
245
What detrimental effect happen to RF energy when it detects a raindrop?
It reflects, refracts and is absorbed by the raindrop
246
# Fill out the below table with regards to weather radar detection
Colour Intensity Rainfall (inch/hour)
BLACK
GREEN
YELLOW
RED
MAGENTA (PURPLE)
1 \<0.03
2 0.03-0.15
3 0.15-0.5
4,5,6 \>0.5
BLANK TURBULENCE
247
What does WX mode detect?
Detects rain storm along flight path
248
What does WX/T detect?
Rain storm along path but adds turbulence area within storm as white. Range of 40nm
249
With weather radars, what does TILT, do?
Adjusts radar angle for takeoff/cruise
250
With weather radars, what does GAIN do?
Adjusts sensitivity of RT
251
On the ground, what is the Maximum Permissible Exposure Level (MPEL) to weather radar
5-15 meters
240 degrees around radar
252
Does the weather radar detect CAT? Why/why not?
No
Because CAT is usually free of precipitation
253
What does forward looking weather radar do? What is it's range
Predictive windshear (PWS)
Looks 5nm ahead, detects 3nm +/- 30 degrees
254
Is FLWR reactive?
No
255
Define severe wind shear
Wind change greater than 15 knots and/or verical change \> 500 feet
256
What aural warnings occur during take off for FLWR? At what distances? And when are these inhibited?
WINDSHEAR AHEAD
Warning 1.5 nm ahead
Inhibited at takeoff between 100kts and 50 feet
257
At what height does FLWR operate automatically at?
2300 feet AGL
258
What height are warnings and alerts generated at?
1500 feet below
259
What does counter clockwise radar detect?
Windshear detection mode
260
What does clockwise radar detect?
WX or MAP
261
What are the aural warnings for FLWR during landing and when are they inhibited?
Go Around, Windshear
Inhibited below 50 feet
262
How does the RF detect microburst?
Doppler effect, frequency shift.
Frequency increases (rain move towards)
Frequency decreases (rain moves further away)
Difference between the two
263
What class is the minimum for FLWR and what is the % for trasnmissive efficiency?
Class B
87% to minimum 82%
264
What is the priority of message?
1. Stall warning
2. PWS
3. GPWS
4. TCAS
265
With the future multiscan radar, what range does it have?
320 nm
266
Where is the VOR/LOC antenna?
Top of vertical stabiliser
267
What does VOR/LOC antenna do?
Supplies RF signals received from VOR stations to the VHF NAV receiver
268
What bonding does the VOR/LOC antenna have?
0.0001 Ohms
269
What does the VHF Nav receiver do?
Processes valid VOR, LOC and G/S signals
270
What systems does the VHF Nav receiver supply received data to?
ADI, HSI and RMI
271
What frequency does ILS opperate?
108-112 MHz but at odd frequencies
108. 10-119.95
e. g.108.10, 108.15, 108.30 etc
272
What frequency range does G/S operate at?
329.15 to 335.40 MHz
273
What frequency does VOR operate at?
108.00 to 117.95 at even
so 108.20, 108.25, 108.40 etc
274
What amplitutes varies, AM or FM?
AM
275
What are the two ground transmitted signals?
Reference
Variable
276
Describe the reference signal
AM by 9960Hz sub carrier signal
Subcarrier FM by +/- 480Hz
277
Describe Variable Signal
Unmodulated RF, 360 degrees at 30 rev/s
278
What are site error effects?
Anything in the way of the ground station
e.g. fences, buildings, terrain, fuel trucks etc
279
What direction does VOR give?
Magnetic north
280
How do you use VOR?
1. Crew select VOR frequency
2. Station IDENT by audio or morse code
3. Bearing is displayed on HSI (360 radials)
4. Select desired course by OBS knob (omni bearing selector)
281
With VOR, what does one dot on the deviation bar (purple/magenta) mean?
5 degrees variation
282
Intrument landing system (ILS), describe how it works
1. LOC ground station transmits two signals either side of the runway
2. Left signal at 90 Hz
3. Right signal 150Hz
(LEFT or RIGHT audio)
283
What does 1 and 2 dots means on LOC deviation bar?
1 dot = 1 degree deviation, 75uAmp of NAV Rx
2 dot = 2 degrees deviation, 150uAmp
284
What does 1 and 2 dots on G/S deviation mean?
0. 35 degrees deviation = 1 dot
0. 7 degrees deviation = 2 dots
285
How does the marker beacon work?
1. When ac passes over outer mark, BLUE MKR comes up. 400Hz picked up
2. When ac passes over middle marker, AMBER MKR comes up. 1300Hz picked up
3. When ac passes over inner marker, WHITE MKR comes up. 3000Hz picked up
286
What are some limitations of the VOR/ILS?
* Limited to line of sight (200nm at 30000 ft)
* depends on sensitivity of Nav receiver
* Power of station
* Terrain (site errors)
* Altitude of aircraft
287
If the aircraft is south of VOR, what comes up?
TO
288
If the aircraft is north of VOR, what comes up?
FROM
289
What sort of deviation is there on LOC and G/S?
LOC - lateral deviation
G/S vertical deviation
290
What is GPWS?
* Ground proximity warning system
* Aural and visual warnings of potentially dangerous flight path relative to ground
291
When is GPWS activated?
2500 feet and below
292
What does GPWS require input from?
DADC and LRRA Systems
293
Does VOR or ILS use GPWS?
ILS does
294
What are the valid signals received by GPWS? What happens if it doesn't receive them?
28vdc
INOP light appears
295
What is the flap logic switch?
Cockpit switch located and guarded when landing with \<25 degrees flaps
296
At what voltage and hz does GPWS become functional?
115V AC and 400 Hz
297
What are the priority of warnings?
1. Whop whoop pull up (MODE 1 and 2)
2. Terrain (Mode 2)
3. Too Low Terrain (Mode 4)
4. Too Low Gear (4a)
5. Too Low Flaps (4b)
6. Minimum (6)
7. Sink Rate (1)
8. Dont sink (3)
9. Glide Slope (5)
298
What is the main purpose of the 3 phase 115V ac electrical Fuel Boost pumps that are installed in aircaft fuel systems?
To provide pressurised fuel to the engines for operations
299
By what two methods can the EGPWS/GPWS 'Too Low Flaps' warnings be silenced during aircafts landing phase, if the trailing edge flaps are NOT selected to the correct EGPWS/GPWS landing setting?
1. Activate the inhibit switch
2. Put the flaps down
300
What are all the indications provided in the cockpit to the flight crew by the MKR Receiver when the aircraft passes over the outer, middle and inner makrer beacons?
You would hear an audible warning in the cabin that would increase in pitch at each marker. You would also see visual warnings in the cabin that would light different coloured light assemblies depending on what marker you are at
301
What factors can affect HF operations?
Atmospheric conditions, ionospheric conditions, solar flares etc
302
Name an electrical problem/fault that would cause the 10amp Tank 1 Aft Fuel Boost Pump circuit breaker to trip?
* Short circuit
* Electric pump motor seizure
303
Breifly describe how the Fuel Boost Pump operates.
1. The circuit is connected to the 28 volt DC bus 1 because it is essential
2. Tank 1 aft boost pump is connect to a relay
3. When the switch the aft boost pump relay (P6) is activated which close A1/A2, B1/B2, C1/C2 switches in the 3 phase circuit.
4. 3 phase circuit is powered via the 115 volt AC XFR Bus 1 and provides power to the aft boost pump which becomes active
5. Aft boost pump relay has now completed its circuit
304
What is the benefit of having three phase 115 Vac power sourced from the aircrafts generator as opposed to having single phase only?
* More efficient
* More reliable
* Lighter
305
What affects does elimination of the CSD/IDG have on the ac power that is generated and what is the benefit?
* Wild generated power signal fluxation (frequency wild) with engine RPM
* More reliable output due to no moving parts
306
What are the benefits by using side bands (USB/LSB) when transmitting on HF?
* More efficient
* require less energy
* produce clearer audio signals
* signal goes further
307
With a forward looking weather radar operating below 2300 feet, when will the radar antenna be operating in the crew selected mode and when will it be operating in the windshear detection mode?
Crew selection mode = clockwise
Windshear detection mode = counter clockwise
308
What are two components installed in the AC where ATC transponder gets altitude info?
1. DADC
2. encoding altimeters
309
Aircraft equipped with TCAS does not have a rotating SSR antenna like an ATC ground station, yet it can be described as a flying ground station. Why?
* 4 direction antenna that pulses intermittently at specific frequency so as to emulate the rotating effect of ground station which outputs interogation signals to other aircraft
310
Excludding LRRA which of the following DO NOT depend on input from the LRRA for their normal ops?
EGPWS
EWIS
FLWR
FFRAT
REU
LRRA
EWIS and REU
311
What method would you use to identify wires?
UV etching
312
What method was used for identifying wires but isn't any more?
Hot stamping
313
Individual cells of the Ni-Cd battery are connected in paralle, series or both?
Series
314
Which of the three TRUs on a 737 supplies the 28V dc battery bus under normal operating conditions?
TRU#3
315
A landing gear repair is taking place requiring the aircraft to be jacked so the wheels are off the ground and electrical power remaining on. What action must the maintenance crew do prior to jacking to ensure data in the DFDR tape is not erased?
Pull the CB from the FDR or ground sense logic circuit
316
The flight crew has removed the boom microphone headset originally tested and certified for the CVR system by Boeing and connect their own personal Boom-Mic into the audio system. What impact could this have on the CVR?
They may not be compliable and not record any voice/audio
317
When does TADS become activated?
It is selected by crew however becomes automatically active if terrain becomes a threat
318
Which is predictive and which is reactive out of EGPWS and PWS?
EGPWS = reactive
PWS = Predictive
319
What happens when you are 60 seconds away from terrain?
Caution terrain
320
What does TCAS use?
* Mode S transponder
* ATCRBS
321
At what frequency does TCAS processor send and receive info?
Send 1030MHz
Receive 1090MHz
322
What is TA and RA?
TA = traffic advisory (another aircraft is in the vicinity)
RA = Resolution advisory (potential conflict exists)
323
With TCAS, if you select N in the ABV/N/BLW switch, what happens?
Detects 1700 feet above to 1700 feet below
324
With TCAS, if you select ABV in the ABV/N/BLW switch, what happens?
Detects 7000 feet above to 2700 feet below
325
With TCAS, if you select BLW in the ABV/N/BLW switch, what happens?
Detects 1700 feet above to 7000 feet below
326
With TCAS, what does a red square, down arrow and minus 03 represent?
* Red square = RA
* Down arrow = aircraft descending \> 500 ft per min
* - 03 = 300 feet below
327
What does a yellow circle with up arrow +05 represent with TCAS?
* Yellow circle = TA
* Up arrow = climbing \> 500 feet per min
* + 05= 500 feet above
328
What does an open diamond and solid diamond represent?
Open diamond = other traffic, no threat
Solid diamond = proximate ac that won't penetrate collision boundary
329
What do the 12 little white dots in TCAS represent?
2 nm radius around AC
330
What are some of the main aural warnings for TCAS and which are TA and RA?
Climb climb (RA)
Descend descend (RA)
Traffic traffic (TA)
Clear of conflict
331
What is the approx range for TCAS?
40nm
332
How far away approx are RA threats?
20-25s
333
How far away are TA threats?
40-45 seconds
334
What information does a 737-300 aircraft’s VHF Navigation Receiver provide for
the GPWS?
ILS
335
List three EGPWS “enhancements” that are pin selectable at the rack connector of
the EGPW Computer (EGPWC)
1. TADS
2. Windshear
3. ALT Callout
336
The aircraft’s Navigation Receiver detects and compares the angle between the
received VOR signal and the course selected by the crew using the Omni Bearing
Selector control (knob). What indications on flight instruments, does the difference
between these two angles provide to the crew regarding where the aircraft is with
respect to the VOR radial?
45 degrees
337
**Re-coupling of the 737-300 Generator Drive shaft to the engine is accomplished?**
On the ground
338
What does EWIS stand for?
Electrical Wiring Interconnection System
339
What does AWG stand for?
Avionics Working Group
340
What instrument is required by ground maintenance personnel to check that the ground connection for such circuits meet Maintenance Manual requirements?
Bonding measure
341
