CONVEX Tech Flashcards
What are the main components of the ADCS
Dual UARBs
Dedicated Links
RCM
Fault Tolerant Hardware
Fault Tolerant Software
What does the UARB network do in very simple terms
Allows the RCM to control all flight essential equipment on a dual network for redundancy.
What flow is information to essential components, one-way or two-way, and why
Two way as the fault tolerant components have their own processors to communicate complex data back to the RCM rather than just simple confirmation commands such as a switch being made. Some non-UARB components on other systems have a one-way flow of information as they are ‘dumb’ components without an individual processor and merely transmit a confirmation signal back that is binary in nature.
What components areSingle UARB Bus Components and only connected to a single UARB only
UARB A - 1 x Battery Junction Box, both PPDMs, 1 x Vote Processor
UARB B - 1 x Battery Junction Box, 1 x Vote Processor
What are Dedicated Links and give some examples
These are links for non-essential equipment directly to the RCM. This links compenents such as navigation sensors, attitude sensors, IFF, sensor payloads etc.
What functions does the RCM perform
Triplex Processing
Uplink command processing
Autopilot command generation
Downlink telemetry
Video data processing
What is an FCA and what does it do
Each Flight Computer Assembly (FCA) is a single board computer capable of independently controlling the aircraft and receiving sensor data. Each FCA outputs an independent stream of control commands and receives flight data from its own set of attitude and navigation sensors. A Cross-Channel Data Link (CCDL) between the FCAs allows them to share sensor data and datalink information.
What is meant by Triplex Processing
There are 3 x FCAs and 3 x GPS/INS, 3 x attitude sensors, 3 x pressure transducers. This allows triple redundancy and triple processing of the signals by each FCA which then uses mid-level voting to decide which signal to use.
What is Mid Level Voting
Mid-level voting is nothing more than selection of the middle
value. Each FCA then sends necessary sensor data to the other
FCAs. The sensor data from all sensors is voted on by all FCAs.
If only one sensor of the three has good quality, then that sensor’s
data is used. Otherwise, the three values are numerically
sorted, and the middle value is chosen. In either case, all FCAs
use the same sensor data.
What do the Vote Processors do
Each of the three FCAs produces two identical command datastreams. One command datastream from each FCA is sent to vote processor 1, and the other is sent to vote processor 2. The vote processors use the quality of the three command datastreams to select an FCA-In-Command. The command datastream from that FCA is sent out on the dual UARB assigned to that vote processor. UARB A is assigned to vote processor 1, and UARB B is assigned to vote processor 2.
How is the FCA-In-Command selected
The vote processors select the FCA-In-Command. Upon startup, they sample the command datastream from FCA 1. If good quality data is received from FCA 1, it is selected as the FCA-In-Command. After this point, the vote processors monitor the quality of data from each of the FCAs. Any time the quality of the datastream from the FCA-In-Command goes below that of any other FCA, the vote processors will select a new FCA-In-Command. They will select the FCA with the best quality datastream.
What are Fault Tolerant Components and what components are fault tolerant
Smart components that have their own microprocessors and can decide if the information being received from each UARB is high quality.
Aileron Servos
Flap Servos
Rudder Servo
Engine Control Servo
Landing gear retract servos
Brake servos
Engine Fuel Interface Unit (EFIU)
Avionics bay input/output (I/O) expander (nose lens heater, ice detector)
Wing I/O expanders (left & right with interface strobe power supplies)
Fuel heater controllers
Individual printed wiring assemblies in RCM
What does the fault tolerant software in the FCA do
This software determines which fault tolerant sensor to use based on mid-level voting.
Each FCA then sends the sensor data to the other FCAs. The sensor data from all sensors is mid-level voted on by all FCAs. If only one sensor of the three has good quality, then that sensor’s data is used. Otherwise, the three values are numerically sorted, and the middle value is chosen. If one sensor is reported faulty, mid-level voting still occurs.
If a faulty sensor fails to its upper or lower limit, the mid-level voting process will still take the faulty sensor’s value into account when determining the middle value. Should the faulty sensor fail to the middle value, its value will be selected, regardless of the health of the remaining sensors.
What happens to mid-level voting after the RCM resets
Mid-level voting is unavailable after an RCM reset. FCA 1 is in command by default after an RCM reset. The pilot must be aware of possible bad data in individual FCAs in order to avoid commanding a bad FCA.
What is an EGI and what does it do
Series of digitial and ring laser gyros that detect aircraft movement and gives that data to its assigned FCA.
Can an FCA only use the data from its correspnding EGI
No, it can use any EGI via the Cross-Channel Data Link (CCDL)
What is the primary and secondary communication pathways for each EGI to the FCA
Primary - 1553 Bus, Secondary - Hardwired RS-422
When using the CCDL, how does the RCM know which EGI to use
Each FCA uses mid-level voting every 20 milliseconds to decide
Once mid-level voting has taken place, what happens next to decide on which FCA is in command
Each FCA submits an identical data stream (via UARB A & B) to each vote processor, these then decide if the data is high quality and then assign an FCA in command.
What happens to the signal after the FCA in command has been decided
The signal from that FCA is sent out on UARB A and UARB B which is then processed by the appropriate remote terminal that uses atitude data i.e. stores, datalink etc.
What would “Nav sensor - positions do not match” or “Autopilot sensors do not match” mean
EGI fault of GPS degraded.
What are the main components of the Attitude, Air Data & Nav System
Everything but the Alpha & Beta sensors and Ku SATCOM are in groups of 3
3 x GPS antennae
3 x EGI
3 x FCA
3 x Airpseed transducer
3 x Altitude transducer
3 x Laser altimeter
3 x Pitots
3 x Static ports
What will happen in Ku if EGI 1 fails
Aircraft will lose link due to EGI 1 providing positional data to Ku SATCOM dish to align it accurately with its satellite.
If FCA 1 fails, why will the aircraft not lose link due to EGI 1 feeding into FCA 1
Data from EGI 1 will route to the other FCAs via the CCDL
How many pitot tubes & static ports does the aircraft have and what do they measure
3 pitots - 2 x left wing, 1 x right wing. They measure dynamic pressure
3 pairs of static ports - 3 on each side of the aircraft. they measure barometric pressure
What does the air that enters a pitot tube do
it is routed to a pressure transducer which calculates an electrical current from the pressure that is exerted. This is then used to give a corresponding airpseed
What does the air that enters the static ports do
it is routed to a pressure transducer which calculates an electrical current from the pressure that is exerted. This is then used to give corresponding altitude data
What prevents the pitots and static ports from become clogged with ice
Heaters
What altitude does the laser altimeter start to provide readouts on the HUD
100 ft AGL
What environmental factor could cause invalid Laser Altimeter readings
dust or moisture in the air
What is activated when the deice system is set to auto
Pitot and static heaters
What triggers the deice system to switch on in auto mode
Ice is dectected on the ice sensor (nose of aircraft) or OAT <10℃
What would you expect to find located on the Alpha Probe and what does each component do
Alpha Sensor - A potentiometer equipped windvane which provides AoA readings to the RCM and is used for Stall Protect
Beta Sensor - A potentiometer equipped windvane which is downlinked in telemetry and isn’t used by the RCM or Autopilot
Yaw String - Give a simple indication of yaw and is visible on the nose camera
OAT Sensor - Provides OAT information to the RCM in order to calcualte TAS, Density Altitude, and indirectly Lift Coefficient. The OAT is also used by the deice system
What is the tolerance of the OAT sensor
±3℃
What sensor should be used for Take-off and Landing Data (TOLD)
Engine Inlet Temperature on VIT 46
What altitude reference is used by default by the navigation system - Barometric or GPS
Barometric - GPS has to be selected by the pilot.
How many satellites are required for a 2D and 3D fix
2D - 3 satelittes, 3D - 4 satellites
What are P Codes in relation to GPS
Classified military precision GPS signals that are way more accurate than commerical GPS. These are loaded using a crypto key
What happens if there are no GPS signals received by the navigation system
The aircraft will use INS only
How accurate is INS
It will degrade by less than 0.8 nm every hour
What is the issue regarding LRE if 2 GPS sensors are reporting erroneous values
Mid-level voting may report an innacurate value which means accurate GDT location may not be achieved for LOS ops. Consider using visual references for aircraft position as HUD telemetry and tracker position may be innacurate
What could cause innacuracies with the navigation system during its startup process
Moving the aircraft as it needs to remain static to get the most accurate initial information
What is the normal “FCA# Stat” and “FCA# Err” codes that would show all FCAs are functioning correctly
FCA# Stat = F7
FCA# Err = 20
What is a Figure of Merit and what would you expect to see
It is a blended indication of the quality of the navigation and autopilot systems.
Code 1 = System is accurate to ≤25m
Code 9 = >5,000m
When are pitot and static heat powered on
Automatically commanded On when OAT is less than 10 °C OAT or any time ice is detected on the aircraft. Once ice is no longer detected and OAT exceeds 12 °C, the deice system commands the pitot and static heat to off or the previous pilot selected state.
What does the autopilot interect with on the aircraft
Flying controls, Engine, Attitude & Air Data System
What does the autopilot control when under autonomous flight
Navigation System, Transponder, Airborne Datalinks, MTS sensor control system, Video data system, SAR
What 2 modes ae there for Direct-To
Airspeed Hold or Airspeed and Altitude Hold
What happens to control sensitivity with Cruise Mode on and off
Control sensitivity is reduced by Crusie Mode
What is needed to enable Cruise Mode
- Any hold mode engaged
- > 110 KIAS
- Stall Protect enabled
When does Cruise Mode turn off
<100 KIAS
What Cruise Mode is on, what override function is activated
Roll limit override
What are the 3 hold modes
Heading, Airspeed & Altitude
What happens if the control stick is moved left or right in Heading hold mode
Nothing, no roll commands are sent to the aircraft
What route will Heading Hold turn the aircraft when a new heading is selected
It turns the shortest distance
What is the lowest commandable speed for Airspeed Hold mode
Airspedd Hold Active - It corresponds to CL = 1.25 with Airspeed Hold active
Altittude Preference Mode - 180 KIAS or 240 KTAS (whichever is slower)
Airspeed Preference Mode - 190 KIAS or 240KTASA (whichever is slower)
Altitude Hold On - airspeed is limited by Dive Priority Mode
How does the aircraft attiitude change to reach a commanded airspeed
There is no direct pitch control, however, the aircraft will respond in pitch to attempt to achieve the commanded airspeed
When airspeed hold is initially turned on what airspeed will the aircraft maintain
The current commanded airspeed. If a new airspeed is required then this will have to be set after Airspeed Hold is turned on.
How many degrees must pitch angle and pitch commanded be within before engaging airspeed hold?
±2 degrees
What is likely to happen with rapid throttle increases during climb-out with Airspeed Hold on
Aircraft will pitch up rapidly and approach stall conditions. If Aileron Tip Stall or Stall Protect is activated, reduce throttle input
What does the Airspeed Limit Override do
Prevents the pilot from setting and airspeed value lower than CL = 1.25 or CL = 1.05wen automatic flap schedule is not active or gear is down.
What happens if the pilot tries to set a commanded airspeed below CL = 1.15
The autopilot overrides the command and sets the lowest possible airspeed to remain within liits. “Airspeed Limit Override” is displayed on the pilot HUD
What does Altitude Hold Mode do
Maintains a commanded altitude
What are the 2 preference modes that can be utilised with Altitude Hold Mode
Altitude Preference Mode
Speed Preference Mode
What does Altitude Preference Mode do
The aircraft attempts to maintain airspeed for the commanded altitude by adjusting the throttle setting calculated by the closed loop power function
What does Speed Preference Mode do
The Aircraft attemts to maintain airspeed for the comanded altitude by adjusting pitch whilst maintaining the commanded throttle setting
In Airspeed Hold Mode without Altitide Hold engaged, how does the aircraft maintain altitude
the AP uses a speed-to-pitch relationship. A change in airspeed is compensated for by the AP which adjusts the pitch of the aircraft toachieve the commanded airspeed
In Airspeed Hold Mode with Altitide Hold engaged, how does the aircraft maintain altitude
Altitude Hold Mode engge means that either Altitude Preference or Speed Preference Mode will dictate how the aircraft achieve the selected airspeed
What are the rate of climb/descent ranges and the defaults
Climb - 100 to 3,000 fpm
Descent - 100 to 2,000 fpm
Default - 1,000 fpm
What happens to the throttle when Altitude Hold is engaged
It has no effect if it is moved
When does speed preference mode turn on
On - ≥CL 1.0
Off - ≤CL 0.9
What is the danger of Speed Preference Mode in a ROZ stack whilst MARSA
The aircraft will depart from its set altitude in order to maintain airspeed and result in height being lost rapidly and a potential airprox or collision
What will happen in Altitude Preference Mode in the same ROZ stack
If the aircraft is unable to maintain the set airspeed and altitude it will maintain the commanded altitude which will mean airspeed will reduce. The AP will maintain the highest aispeed possible whilst maintaining altitude
What is Best Climb Speed Override and what triggers it
The DFCS will override the comanded VSI if it exceeds the calculated rate of climb limits for the aircraft. The aircraft will replace the commanded VSI with the maximum calculated VSI.
What is Dive Priority Mode and when is it active
Automatically engaged during a descent in Altitude Preference Mode when within 5 kts of 190 KIAS or 240 KTAS. It prevents the aircraft from exceeding VNE. It automatically disengages when outside of dangerous parameters
How does the aircraft prevent VNE from being exceded in Dive Priority Mode
Engine is set to idle and airspeed is controlled by pitch
What is Speed Priority Override and how is it triggered
At higher airspeeds, with airspeed and altitude hold engaged, altitude preference mode will automatically be selected. In this flight mode, the aircraft controls altitude via the pitch command.
Altitude takes priority over airspeed and additional protection is needed to prevent stall.
If the indicated airspeed slows to a corresponding CL of 1.1 or stall speed plus nine knots, whichever is greater, the aircraft enters speed priority override mode,
What actions does the aircraft do when it enters Speed Priority Override
-Airspeed-to-pitch is enabled
-Airspeed command is set to the appropriate best climb speed - a speed that will achieve a CL of 1.0
-The warning: “Best Climb Speed Override” is sent to the GCS
When will the aircraft exit Speed Priority Mode
-Airspeed is not less than 2 KIAS below the best climb speed and the aircraft vertical speed is greater than the altitude-to-pitch controllers commanded vertical speed
-Aircraft is above the commanded altitude and indicated airspeed is above the minimum airspeed command (corresponding to CL = 1.25)
What is Aileron Tip Stall Override and how is it triggered
It automatically decambers the ailerons when Angle Of Attack (AoA) increases above +5° to prevent the wing tips from stalling. This feature is activated when cruise mode is off or stall protect is turned on. It is only deactivated if cruise mode is on and stall protect is off.
Why is Aileron Tip Stall Override required
It automatically decambers the ailerons when Angle Of Attack (AoA) increases above +5° to prevent the wing tips from stalling. This feature is activated when cruise mode is off or stall protect is turned on. It is only deactivated if cruise mode is on and stall protect is off. This feature deflects the ailerons down by an equal amount on each wing (if wings are level).
What AOA is required before ailerons will deflect
ᐩ5° to ᐩ9°
How is Aileron Tip Stall Override dealt with in relation to pilot inputs
The Aileron Tip Speed Override deflections are added to any pilot inputs thus decambering the wings more rather than less.
What is the maximum deflection possible
8° at AOA readings above +9°
What is Stall Protect and when is it enabled
Prevents stall by limiting aircraft AoA. Stall protect is turned on and off by the pilot, but only takes effect at speeds below 120 KIAS. Stall protect is automatically disabled at speeds 120 KIAS or greater, and automatically turns on below 120 KIAS when autopilot is engaged. Stall protect will not turn on, if the pilot has it commanded Off and with no autopilot engaged.
How does Stall Protect prevent the aircraft from stalling
The aircraft deflects the ruddervators down when AOA exceeds limits
What AOA range is required for Stall Protect to activate
Engages when +7° AOA and disengages when AOA is <3° AOA
What is automatically turned on with Stall Protect
Cruise Mode
What is the problem with the stall speed displayed on the HUD when Cruise Mode is on
When in cruise mode the stall speed indication on the HUD represents a CL=1.5 regardless of flaps settings, which is approximately the stall speed with flaps at 30°. Reference TO 1Q-9(M)A-1-1 for accurate stall speed computation.
What is Roll Limit Override
The roll limit override feature uses CLVmin limits to limit command roll to maintain a safety margin between the aircraft’s indicated airspeed and its stall speed due to roll angle.
What is roll limited to during autopilot controlled turns
Roll is limited to 30 degrees during autopilot controlled turns.
What CL is used to limit roll
Auto flap - CL = 1.25
Manual flap - CL = 1.05
When is Roll Limit Override enabled
When any of the following are true:
-Heading hold is on
-Stall protection is on
-Airspeed hold is on
-C-Band LOS is lost link
-In a SATCOM link type
What happens if the pilot commands a roll angle that is unsafe
The AP automatically limits the aircraft roll to a safe limit and displays “Roll Limit Override”
What is Roll Shaping
Limits the roll rate of the aircraft regardless of what roll rate the pilot commands to prevent a lost-link scenario due to rapid roll movements
What is Standard Rate Turn
Limits aircraft autopilot commanded turns to /3°/second heading change.
What is Standard Rate Turn
Limits aircraft autopilot commanded turns to /3°/second heading change.
What is the max bank angle for turns >30° in heading change
Autopilot modes - 30° roll
Emergency Mission - 20° roll
What is Bank Angle Limit (Dial-a-bank)
The pilot’s roll commands are software limited based on the flight mode and lift coefficient of the aircraft
What is max bank angles that can be set and used
If any of the following are engaged the bank angle is limited to 10° to 30°:
-Heading Hold
-Nav Mode
-Direct-To
-Lost LOS link mode
If none of these modes are engaged the limit is 40°
What CL is required for “Stall Conditions - Exceeding Limits”
commanded bank angle exceeds a CL = 1.25
What is Sideslip Protect
Keeps the aircraft from entering an unwanted sideslip condition during turns
How does the aircraft prevent the sideslip condition
The rudder and ailerons are coordinated
How is Sideslip Protect turned off
It is permanantly on and cant be turned off
What is included in the aircraft weight calculation by the autopilot
Weight = Ramp weight - (fuel burnt + weight of released stores)
How many Op Missions and Emergency Missions can be used at a time
1 of each, but several extras can be stored in the GCS
What are the two kinds of waypoints available and how are they different
Normal Waypoints - The aircraft will turn prior to the next waypoint in order to make a smoother flight path.
Flyover Waypoints - With flyover waypoints, the aircraft will attempt to fly directly over the waypoint prior to turning
What happens to the Emergency Mission should an RCM reset happen
Only the last 20 waypoints are saved
What would happen if the transmitters are set to off on an Emergency Mission, and why
When aircraft is lost link and flying an emergency mission, emergency mission waypoint transmitter settings (transmitters off/on) will take priority over preset Lights-On range settings. If the emergency mission waypoints set transmitters off, link cannot be regained until the RPA executes the last six waypoints, regardless of preset Lights-On range setting.
What happens when the aircraft gets to the last 6 waypoint sof the EM
When the aircraft reaches the last 6 waypoints of the EM it will refly them over and over. When it gets to the last waypoint for the first time the LOS transmitter is turned on. The aircraft will fly this route until the timer runs out or fuel is depleted.
What does the aircraft do when the lost link timer reaches zero
Engine is shut down, gear commanded down, airspeed command set to stall + 15 kts and altitude hold disabled. The aircraft will continue around the last 6 waypoints until it crashes.
What is the default EM lost link timer
96 hours
What are the arming time when LOS and Ku
2 seconds and 5 seconds
What criteria are required for the aircraft to use High-Speed Lost Link Logic
> 50 KIAS
What autopilot mode will the aircraft use when lost link
CL >1.0 = Airspeed Preference Mode
CL <0.9 = Altitude Preference Mode
What happens to the aircraft if it loses link below ILLA
If the aircraft is below ILLA, it will enter climb state and begin flying towards a flyover waypoint the RCM creates 2.5 NM in the direction of magnetic Initial Lost Link Heading (ILLH). Altitude command is set to ILLA plus 150 feet. Airspeed hold mode and altitude preference mode are turned on, airspeed command is set to climb airspeed, and engine power is set to 100%.
The aircraft will fly a wind corrected heading until crossing the flyover waypoint, at which point it will initiate a turn to enter a clockwise hexagonal loiter. The loiter has a 2.5 NM diameter and will be flown until reaching ILLA or until 30 minutes has elapsed, at which point the aircraft will begin the emergency mission.
What are the key Lost Link Arming timings and what happens at each
Arming time + 1 second - The RCM sets Rx 1 to the primary uplink frequency and Rx 2 to the secondary uplink frequency.
Arming time + 10 seconds - The RCM toggles Rx 1 and Rx 2 between primary and secondary uplink frequencies every 10 seconds.
Arming time + 100 seconds - The RCM will set Rx 1 to direction and set Rx 2 to omni and toggle Rx 1 between the directional and omni antennas every 180 seconds.
Arming time + 120 seconds or Airborne Modem offline - RCM sets C-Band antennae pointing mode to auto
Arming time + 180 seconds - The RCM sends a reset command to the airborne
modem every 180 seconds until the lost link condition is remediied.
What happens to the engine if it flames out whilst lost link
Immediately (as long as >20 secs lost link)
Engine hot
Engine speed 100%
Engine power 30%
Condition lever, set to normal
Engine out for 40 continious secs:
Lower gear
How long does the Airborne Modem take to reset
Approximately 60 seconds to reset.
If a lost link condition exists after 180 seconds but the Airborne Modem was commanded off
It wont reset or turn back on.
What happens to mid-level voting after and RCM reset
Mid-level voting is unavailable after an RCM reset. FCA 1 is in command by default after an RCM reset. The pilot must be aware of possible bad data in individual FCAs in order to avoid commanding a bad FCA.
What do the different coloured arrows on the tracker compass rose mean?
Orange - GDT Azimuth direction
Magenta - aircraft Heading
What do the differnet coloured Markers (◀︎) on the tracker compass rose mean?
Top - Heading Hold Preset Marker (Moves with control stick to referencea proposed heading hold command)
Bottom - Heading Hold Marker (present heading hold command)
What happens to the engine power when Landing Configuration is commanded
The engine power command immediately updates to the throttle position which means the aircraft could rapidly lose airspeed if not set high enough to maintain airspeed and altitude
What happens to the aircraft if a rack swap is attempted in flight and one of the 4 control levelers is in the incorrect postition
The aircraft will disable uplink and enter Lost Link profile
What modes of operation does the C-Band LOS system and Ku-Band SATCOM system operate
C-Band - Standard (analogue video) and Digital
Ku-Band - Digital only
What happens if the encrytion keys dont match between the GCS and the aircraft
A link cant be established
What does “Datalink Signal Strength” mean
the quality of the signal is sufficient to establish a link, however, it does not denote whether or not the proper encryption keys are loaded.
What can a controlling GCS do to cause a rack lockup in a shadowing GCS
Cycling SMS power during GSMS verification. this can be prevented by the controlling GCS performing GSMS verification prior to allowing a shadow or the shadowing GCS disabling RL whilst the GSMS verification process is ongoing.
What is the “Ku Air RF Stat 1” and nominal “DL Delay” that is acceptable; when and where would you check these values
these would be checked if the aircraft suffers several link hits or during H/O
VIT 10 - DL Delay RSO = 0.9 - 1.3 secs
VIT 28 - KU Air RF Stat1 = 1B
What are the datalink priorities
The aircraft will prioritise active links in the following order of priority:
1. Direct connect
2. C-Band LOS 1
3. C-Band LOS 2
4. C-Band DLOS
5. SATCOM
What kind of Ground and Airborne Modem does the Block 1/Block15 system use
Ground - 1SL-NS-SLMA V2 9
Air - IMA
What antennaes can be used for LOS Mode
Omni and Directional Antennaes
How many Tx/Rx are there on the aircraft
2 x Tx, 2 x Rx
How much power is tranmitted in High/low power modes
10w and 1 milliwatt
How many C-Band antennaes are used to maintain LOS
2 x directional antennae and 1 x omni
What Tx/Rx are the upper an lower antennae linked to
Upper (Directional) - Tx2/Rx2
Lower (Omni & Directional) - Tx1/Rx1
How does the aircraft select which antennae combination to use for uplink
It selects that which has the best uplink data stream (not always the strongest signal)
What is the max range of the Omni, Horn (wide) and Dish (narrow) Antennae
Approx 1.5 nm, 5.5 nm and 130 nm
Can both aircraft Rx/Tx sets operate simultaneously transmitting and receiving datalink info
Yes. The system can also support one uplink and both downlinks if required
What data is contained in the uplink and downlink
Uplink - commands and audio from GDT to aircraft
Downlink - Combined video, audio and telemetry to the GDT.
How does muxing play into what is sent via each downlink
Muxing allows a unique video source to be sent on each downlink i.e. MTS and nose cam
What navigational data source does the GDT use to point the antennae at the aircraft
GPS data from the aircraft is used by the GCS to automatically point the GDT at the aircraft
What data is transmitted to the aircraft via the Return Link
VQ Video
Encoder (HD) Video
Telemetry
Radio transmissions
Lynx SAR or AH
What data rate is the CL and RL
CL - 200 kbps
RL - up to 6.4 mbps
What is the approximate current usage by the SATCOM antennae
Approx 15 amps
What is the function of the airborne modem
Central control and processing point for Ku SATCOM equipment
What is the approximate current usage by the Airborne Modem
Approx 10 amps
What does the SLMA do
Interface between the PSO workstation and the KU-Band SATCOM terminal in the GCS
What is the role of the Video Decoder Assembly
It converts a digital video signal from the aircraft into an analogue signal that is viewed by the crew
What are TDES keys and how do they work.
Triple Data Encryption Standard (TDES) is a civilian encryption standard which encrypts data using a random 64 bit key (1.8 x 10^19 combinations) this initial encryption is then encrypted a further 2 times with anopther random encryption key, which equals 5.823 x 10 ^54 possible combinations. This then encrypts the CL/RL
What happens to TDES keys if power is lost t the RCM or ground modem
TDES keys 1 & 2 are lost and need to be refilled
What happens to the aircraft link if the TDES keys are lost in flight
the aircraft will still maintain link but the CL/RL wont be encypted
What is the danger of operating in Clear Text rather than Set 1, 2 or 3
In clear text the aircraft can lose RL. This is becuase for an RL to be maintained it needs constant data, in Clear Text this doesn’t happen. In Encrypted mode the encryption data is passed constantly so the integrity of the link is maintained.
What precautions must be taken when C-Band is not available and selecting RL/CL key sets?
Always select and verify RL key set is functional before selecting CL key set. This is becuase if the RL key doesnt connect the CL key will be working (prior to selecting new keyset) and can be used to send the new key set to the aircraft again.
Why do the Apply and Ok buttons grey out for approx 10 secs when selecting a key set?
It allows the GCS and Aircraft to sync the key set. On rare occasions it can take 30 secs.
What voltage does the SG/DDBA/Battery produce
SG - 9kW, 28VDC (at sea level)
DDBA - 28VDC via DCPS
Battery - 25.2VDC & 14Ah each battery
If Bus 1 Fails and the batteries are dead, what Bus 2 Systems wont function
PPDM 1 - SMS, Hellfire Inverter, MTS, Video Encoder.
PPDM 2 - SAR, Air Handler
What happens to the fuel heater when voltages drop <26VDC
Switches off automatically
What voltage must landing gear be lowered by to ensure it lowers fully
Lower BY 22V
What services are switched/unswitched and not on PPDMs
Switched - Ice Detector, Lens Heat, Fuel Heater, Nav/strobe lights.
Unswitched - Control Servos, DEEC
What are the electrical limits (volts & amps)
Normal Operating
Bus 1 - 0-240A/25-30V
Bus 2 - 0-120A/25-30V
DCPS - 0-100A/25-30V
Maximum
Bus 1 - 280A, 32V
Bus 2 - N/A
DCPS - 120A/32V
What amperage will DCPS HSSW disable and what current will they re-enable
Off - 120A, on - 100A
What does the SG do during start and in flight
Start - Performs the role of a starter motor
Flight - Become a generator
What happens to the SG at altitude in terms of power output
Power output is derated by approx 30% to 6kW (this is dependent on SG internal temperature at altitude
How is the SG cooled
Ram air on the underside of the engine cowling
Where is the DDBA connected to
Engine auxilliary drive
What is the job of the DDBA
Provides power to the Ku SATCOM via the High Side Switch (HSSW) and to critical avionics
When does the DDBA enable switch no longer work
> 50 kts when it is set to on automatically regardless of the setting of the switch
How is the DDBA cooled
Ram air on the underside of the engine cowling
What is the DDBA max temperature and maximum normal operting temperature
Max - 210℃
Max normal operating - 190℃
What limits DDBA power output
Temperature and engine speed.
What happens when DDBA exceeds 190℃
Max power output decreases linearly to try and lower temperature. if temp >210℃, then DDBA is limited to 500W output
What will reducing the load on the DDBA do to the alternator temperature
It will have minimal impact on reducing the temperature
What prevents a single battery fault from bringing down the entire bus
A diode on each battery
What prevents the batteries from degrading with temperature at altitude
Each battery has an internal heater
What is the Generator Control Unit (GCU) and what does it do
Controls the voltage output for the SG and prevents over/under frequency
What is the Power Converter Unit (PCU) and what does it do
Manages engine starts
What is the Engine Start Sequence Module (ESSM)
Manages sequence of solenoids, valves, ignition relays and fuel shut-off valves
What does the DC Power Supply (DCPS) do
Converts AC power into 2.8kW 28 VDC power via the HSSW
What does the DCPS provide pwoer to
Airborne Modem and Ku Antenna Control Unit
When are the DCPS HSSW commanded on
When any of the following occur
1. Ku IMA Power is turned on
2. Ku IMA Reset button is selected.
3. Airspeed is >50 kts
Fault and failure conditions and/or exceeding limits could disable the DCPS HSSW = no power to Ku SATCOM, how is this re-enabled
Ku Airborne Modem reset
What is the ORing Diode Module
It allows bus 2 to provide power to Ku SATCOM equipment. The bus with the highest voltage will power the Ku Antenna Control Unit (ACU) and airborne modem
What does the Battery Junction Box (BJB) do
Distibutes power to each Bus but allows physical separation of each bus for power redundancy and to protect circuits
What items will turn off automatically if bus voltage drops <23v
SMS, Hellfire inverters, SAR, MCM, Air Handler, Laser Altimeters
What are the two governors on the engine and what do they do?
Underspeed - limits engine minimum speed.
Overspeed - Limits engine maximum speed
What does the speed lever control on the ground and in the air
Ground - sets idle RPM.
Air - Controls propeller pitch via the propeller governor
What will happen to the engine if the engine driven fuel pump fails
The engine will still function, but will have limited maximum power available to the engine.
How are fuel shut-off valves kept open/closed if electrical power is lost
Magnets hold the valve in the last postition they were in prior to power being lost.
What does the pilots throttle do in the event of a DEEC failure
Provides backup engine control in flight and conrols propeller pitch settings below Flight Idle
What does the DEEC primarily do (in very broad terms)
Provides RPM, power and reverse thrust capabilites to the pilot
What is the DEEC operating range in flight
82% - 100.5%
What functions does the DEEC provide during start
Set the timing that allows fuel into engine & igniters on (10%), starter and igniters off (60%), Single Redline Limits (SRL) activations switch, auto fuel enrichemnt, SRL EGT conditioning, closed loop power control and engine/DEEC fault monitoring
How many thermocouples are there to measure EGT and how is the temperature calculated
There are 8 x thermocouples on the T5 stage of the engine (past the 3rd turbine stage) - An average reading is displayed to the GCS
What does the Temperature Compensator do
It allows one set of performance charts to be used for all engines despite slight variations in build tolerances and efficiency. It receives the raw signal and compensates an outpur signal to the DEEC.
What does the Delta Pressure Ratio Transducer do
In simple terms, it supplies a representative voltage to the DEEC for temperature calculations based on inlet and exhaust gas pressures.
Why does the engine have a Single Redline Value and not a temperature output
The actual EGT limits vary based on ambient conditions usch as density altitude & local temperature. To make this easier for the pilot, the DEEC calcualtes a Single Redline Limit that is based on ambient conditions that can be used as a single temperature limit.
If the DEEC fails, what must the pilot do for EGT limits
Consult the EGT limit chart in Sect 5
What is Negative Torque Sensing and what does it do
Negative torque is generated when the engine flames out and the prop windmills. The NTS causes the prop to semi-feather. When the engine restarts oil pressure is restored and the prop will unfeather
Why have an NTS and feathering system
The NTS doesnt fully feather the prop. It creates a feathering cycle - when the prop slows down the blade angle increases and RPM increases which triggers the NTS sensor and the cycle repeats. The condition lever fully feathers the prop.
What does Closed Loop Power do
Provided a linear throttle movement that is identical across airframes as it uses engine torque as a feedback signal which adjusts engine power accordingly. Open loop power is inconsitent between airframes
What happens to closed loop power fails in altitude mode
Engine will be set to 100% regardless of speed lever setting. When Alt Mode is disengaged then speed lever will control engine speed again (unless a DEEC fail).
When do the igniters switch on and off during start
On - >10% RPM, Off - 60% RPM
What is the automatic restart RPM
if engine drops below 78% RPM then igniters are turned on automatically.
What is the normal DEEC fuel control sequence in broad terms from throttle command to change in engine power
- DEEC receives throttle command from the RCM
- DEEC causes the engine to bleed air
- The bleed air drives the fuel metering valve = engine power is controlled.
What happens mechanically during DEEC failure
- Manual throttle is enabled
- Throttle servos moves to regulate bleed air which feed to the fuel metering valve
What does DEEC backup mode NOT do
Automatic control of engine speed, engine torque or EGT
What happens to EGT in backup mode
There is no direct limiting EGT, the engine is instead limited by torque which limits engine power and by extension EGT. Based on OAT and density altitude torque wont exceed 70%, this means airspeed and altitude may not be able to be maintained.
What happens to the torque limiting function in landing configuration
It is disabled to allow for go-arounds which means engine limits could be exceeded
What happens to engine RPM when DEEC Backup Mode is entered in flight
Engine speed is set to 100% - speed lever and hold modes will have zero effect on engine speed until normal DEEC oeration is restored.
When transferring from backup to DEEC mode, what must be done to the Speed Lever?
Set to 100% as the DEEC will immediately set the engine to the the commanded RPM and torque which coulc cause damage to the engine
What does each position of the condition lever do
Full forward - normal
Halfway - shuts off fuel
Fully back - feathers prop and fuel shut-off
What does the throttle and Speed Lever do
Throttle - Controls fuel flow to engine which in turn adjusts blade angle to maintain the Speed Lever commanded RPM setting
Speed Lever - Sets the engine RPM, but doesn’t control it.
What is the critical speed range of the engine and what are the RPM speeds associated with it
This is the natural dynamic frequency of the turbine shaft where damage can occur in the 18% - 28% range
What RPM figure will the engine automatically try a restart
<78%
How does an automatic restart vary between normal and lost link conditions
Normal - Engine restarts, if RPM is <60% RPM will turn on the unfeather pump. The restart can be over-ridden by the pilot.
Lost link - Igniters are forced on as soon as a lost link condition is detected. An engine restart will be attempted even if the engine was shutdown prior to lost link.
What happens to fuel in the manifolds after shutdown and how is this prevented
Fuell will leak onto the ground, to prevent this the engine bleeds air to purge the manifolds of fuel
When are the igniters turned on automatically during flight?
When icing conditions are detected. When icing is no longer detected then the igniters remain on for 5 minutes before being commanded off
What happens to AH when a lost link condition happens?
During a lost link event, payload power switches ( AHC PPDM switch 5 and switch 6, or SAR+AHC PPDM switch 7) will not be able to disable power to the AH Cheeks payload. The payload power is shed automatically 52 seconds following lost link.
What happens to AH if the batteries are sourcing current?
The Lynx SAR transmitter is disabled 51 seconds after the aircraft enters high speed lost link condition. The Lynx SAR REA, GAA, and SAR+AHC Air Handler Cheeks are load shed if batteries are sourcing current. If batteries are not sourcing current, the REA, GAA, and SAR+AHC Air Handler Cheeks are set to match the previous GCS command (e.g., On or Off).
What happens to AH if the batteries are sourcing current?
The Lynx SAR transmitter is disabled 51 seconds after the aircraft enters high speed lost link condition. The Lynx SAR REA, GAA, and SAR+AHC Air Handler Cheeks are load shed if batteries are sourcing current. If batteries are not sourcing current, the REA, GAA, and SAR+AHC Air Handler Cheeks are set to match the previous GCS command (e.g., On or Off).
How many ailerons does the aircraft have
2 on each wing
Where on the wing are the aileron
outer 1/3
How many flaps does the aircraft have
2 on each wing
Where on the wing are the flaps
Inner 2/3
What airspeed are flap auto controlled
> 134 KIAS or if gear is up and airspeed hold is on
When will flaps return to manual control
<130 KIAS or gear is down or airspeed hold is off
What happens to flaps that are manually controlled and between 120 KIAS & 134 KIAS
The autopilot limits the defelction of the flaps and overrides the flap level settings
What angle is rudder input limited to from the pilot
±6° in preprogram mode. Normally 30° if not in preprogram mode.
How many servos are included in the flying control system (according to TOs)
16 - 4 on each wing, 2 on each ruddervator, 1 for the rudder and 3 for landing gear
What happens to ruddervators if a servo fails
The SAS compensates for the defective ruddervator. It is worth noting, the aircraft has a rudder as well.
How are flight control servos powered
28 VDC from both Buses - this is then converted to 5 VDC or 12 VDC
What allows power to be drawn from either bus, but prevents a single Bus fail from bringing down the other Bus
Diodes and 15A fuses on each servo
How is servo temperature monitored
Temperatre sensors on servo and the servo motor
What happens to a servo if it has an over-current and what amperage triggers this
Servo is frozen in position and current required is 10A
What control surface causes the aircraft to pitch up/down
Ruddervators
