AS 21 - ADM CADC Universal UNS 1C FMS Flashcards
Review Questions
What does the MEMORY light on the Doppler indicate?
A loss of valid returns on two or more beams
Review Questions
List the major components of the AHRS
Remote compass transmitter - Flux valve
AHRS control panel
AHRU
Define Static Pressure
The atmospheric pressure at the aircraft altitude unaffected by the motion of the aircraft
Actual static pressure depends on what?
Air temperature and density
Define Dynamic Pressure
The pressure which is due to the motion of the aircraft
Does Dynamic Pressure increase or decrease with air speed?
Increases
Pitot or total pressure (H) is a measure of what?
Static + Dynamic pressure
or
H = P + q
If an aircraft moves faster through the air what happens to the pitot pressure?
Pitot pressure increases
Dynamic pressure can also be expressed as?
q = H - P
What is the only output of a Pressure Sensitive Altimeter?
Static pressure
A Pressure Sensitive Altimeter displays an altitude that corresponds to what?
The sensed pressure in the ICAO standard atmosphere
A Pressure Sensitive Altimeter can correct for what? What can it not correct for?
It can correct for a pressure which is different from ISA
But not a temperature that differs from ISA
What are the errors for a Pressure Sensitive Altimeter?
Instrument Error
Position Error
Lag or Hysteresis
Temperature Error
Briefly describe the Instrument Error
Due to construction defects (friction)
Correction card carried
Briefly describe the Position Error
Caused by positioning of the static vent
Can be corrected by repositioning or a correction card
Briefly describe the Lag or Hysteresis Error
Mechanical lag between gears and capsules
Reads low on climbs and high on descent
Can be reduced by careful design
Briefly describe the Temperature Error
Largest error
Due to ICAO calibration
Rate of change of pressure with altitude depends on temperature
Corrected with Jeppesen computer
How does the Airspeed Indicator function?
Inputs the static and pitot pressure to find the differential pressure
The size of the capsule varies as the difference between the static and total pressure (differential pressure) varies
What are the DADC components?
2 pitot heads
2 static heads
2 temperature bulbs
2 Digital Air Data Computers (DADCs)
How is pitot pressure measured?
By placing a probe directly in the airflow around the aircraft
How does a static port work?
A plate with holes or slots sit perpendicular to the airflow
The slots lead to tube which are attached to instruments requiring static pressure
The pressure in the tubes is the static pressure at that altitude
How is temperature measured for the DADC?
A sensing device which is placed in the airstream
The thermometers contain temperature probes placed in temperature bulbs.
Each probe provides a resistance value equivalent to an OAT
What is true regarding the DADC temperature readings?
The sensors will always read a temperature which is higher than the actual OAT due to friction heating
How can temperature readings be corrected in the DADC?
Automatically via the ADC
Mathematically using the Jeppesen
What are the inputs for the DADC?
Pitot pressure
Static pressure
Temperature
What are the outputs provided by the DADC?
TAS Pressure altitude OAT Maximum operating speed Uncorrected pressure altitude (for the NTS only)
Which DADC outputs are for the pilot/ co-pilot only?
TAS
Pressure altitude
Define Indicated Airspeed
Airspeed shown on the ASI
Define Calibrated Airspeed (CAS)
IAS corrected for instrument and position error
AKA Rectified Airspeed (RAS)
Define Equivalent Airspeed (EAS)
CAS corrected for compressibility
Omitted below 250 kts IAS
Define True Airspeed (TAS)
EAS corrected for pressure and temperature
What does the memory aide ICE-T stand for?
IAS
CAS
EAS
TAS
What are the Raw Data components received from the DADC inputs?
IAS
ALT
VSI
Describe the Flight Management System
A fully integrated nav management system designed to provide the pilots with centralized control for the computer based flight planning and fuel management.
What is the FMS capable of navigating along?
Pilot-programmed flight paths, including SIDs, airways, in-flight maneuvers, holding patterns, STARs, approached and runway data
What are the UNS-1C (FMS) components?
UNS-1C CDU x2 Data Transfer Unit (DTU) x 1 Airdata Converter Unit x 2 Glareshield advisories x 2 GPS antennas x 2 Config module
How does the Kalman filter work for the FMS?
It blends the 2 GPS and IRU positions to derive the “best computed position”
Describe RNAV
A method of navigation that permits aircraft operation on any desired course within the coverage of station-referenced nav signals or within the limits of a self-contained system capability, or both
What are the advantages to RNAV?
Nav does not need to be beacon to beacon Can program routes into FMS Conserves flight distance Reduces congestion Allows flights into airports without beacons
Describe RNP
Required nav performance: A statement of navigation performance accuracy necessary for operation within a defined airspace
Arcs or fire
What does the UNS-1C use from the IRS?
True headings which are then converted into a magnetic course which is displayed on the EHSI
Where can the CT-142 not fly?
Latitudes above 73N
Standard Jeppesen data includes what?
VORs, NDBs, enroute intersections, airports
Extended Jeppesen data includes what?
SIDs, STARs, approach and runway info for selected airports
Extended database for all hard surface runways over 3 000 ft
Regarding Receiver Autonomous Integrity Monitoring (RAIM):
4 satellites:
5 satellites:
6 satellites:
Provides what?
4 satellites: Provides 3-D position
5 satellites: RAIM
6 satellites: Fault detection exclusion (FDE) -> IDs and drops a bad satellite
What is HIL?
Horizontal Integrity Limit (HIL) describes the size of error that the FDE can exclude
HIL depends on what?
Depends on the number of satellites and the satellite geometry
If the HIL is exceeded what happens?
GPS integrity warning is given
RNAV approached require how many satellites?
5
What does the Vertical Navigation function allows?
To define a desired vertical flight profile along the flight plan route.
Review Questions
How do we measure static pressure?
Static port or vent
Review Questions
What is the ideal orientation of the static sensor with regards to the airflow.
The vent should be positioned so that none of the airflow enters the holes
Review Questions
How we we measure pitot or total pressure?
Pitot tube
Review Questions
What is the ideal orientation of the sensor with regard to the airflow?
The tube should be oriented so that the maximum amount of the airflow due to aircraft motion enters the hole in the probe
Review Questions
What are the components of the DADC?
2 pitot heads
2 static heads
2 temperature bulbs
2 Digital Air Data Computers (DADCs)
Review Questions
What display instruments receive raw data?
IAS (PLT)
ALT (PLT SBY)
VSI (PLT)
