AMEM10019 - AVIONICS TEST 4 Questions & Answers

what are the 5 basic navigation systems? - ANSWERS1. pilotage - flying by landmarks 2. dead reckoning - knowing your heading and speed, work out where you're going 3. celestial navigation - using time and angle bwtn known celestial object (moon, sun, etc) 4. radio navigation - GPS, ILS, VOR, ADF, etc 5. inertial navigation - INS and ADIRU what is INS? what does it stand for? - ANSWERS- inertial navigation system - advanced navigation concept designed as an integral part of the avionics system - provide steering commands to autopilot to steer the airplane through predetermine waypoints - accurately determine an AC position using internal sensing devices what are some features of INS? - ANSWERS1. auto self-alignment and calibration are accomplished each time the INS is turned on 2. does not require any input from navigation aids external to the AC 3. continuously monitors its on performance and warns when signals are unreliable 4. present position, waypoint and destination data are easily entered by using a keyboard 5. performance can be improved during flight by making a position fix when accurate present position reference is available what are the 3 laws of motion? - ANSWERS1. body continues in a state of rest, or uniform motion in a straight straight line, unless acted on by an external force 2. the acceleration of a body is directly proportional to the sum of the forces acting on that body 3. for every action, there is an equal and opposite reaction an aircraft moves in 3 dimensions over the earth's surface, how many degrees of freedom? - ANSWERS6 degrees of freedom - 3 translation (N/S, E/W, UP/DWN) - 3 rotational (roll, pitch, and azimuth) what is a gimbal platform - ANSWERS- plat that effectively decouples the inertial reference system from the airframe and provides all-attitude freedom and rotation - AC are seldom perfectly lvl in flight, all airborne accelerometers must be mounted on gimbal plat - consist of 3 gyros, which stabilize the unit the combo of gimbals and gyroscopes creates a platform that.... - ANSWERS- remains level in any AC attitude - does not sense changes in AC attitude, the output signal accurately measures changes in accel - signal is amplified and sent to INS comp INS is capable of continuously updating what? - ANSWERS-position -ground speed -heading and distance -time to destination what is used to detect acceleration? - ANSWERS- accelerometer - sense change in velocity - consists of a small weight suspended between two spring - acceleration sensed in the horizontal direction causes the mass to compress one of the supporting springs, and to stretch the other - must be kept perfectly level as to not misinterpret gravity as acceleration what is a strap down inertial navigation sys? - ANSWERS- uses solid state parts, including the laser gyro - eliminates the limitations of gimbals, bearings, torque motors and other moving parts - ring laser gyro uses two laser light beams to measure angular rotation - sys uses a helium neon gas combo, and the two laser beams are circulated in a contrarotating triangular path - mirrors are used to reflect each beam in triangular area - resonant freq of each laser is a function of its optical path length and when at rest, both beams travel equal distance and have identical freq what change is measured by photosensors and converted to a digital signal? - ANSWERSthe two resonant freq of the individual beams in ring laser gyros what is laser lock? - ANSWERS- during low gyro rotation rates, the 2 lasers can become coupled together. - to prevent loss of information during low rotation rates, a dither motor is installed which vibrates the gyro assembly what are the components in an INS system? - ANSWERS1. Mode selector unit - allows selection (align and nav). READY NAV light luminate to indicate INS high accuracy alignment has been attained 2. Control Display Unit - used to insert present position for INS alignment. this MUST be done with the AC NOT moving. can be done through the MCDU 3. inertial reference unit - sense and compute linear accelerations and angular turning rates (6 thingy). AC power fails, switches to AC battery what is initialization or alignment? - ANSWERS- a process that is initiated manually when the AC is on the ground in a parked condition - phase of OP the sys determines where it is - crew enter raw position data in LAT and LONG values - the INS/IRS system then calculates the position to a very precise value newer aircraft have a sys known as ADIRS. What is it? What does it provide? - ANSWERS- Air Data Inertial Reference System - unit contains air data and inertial reference in one single unit - provides alt, airspeed, temp, attitude, present position what are the components to the ADIRS - ANSWERS1. air data modules - calc airspeed, altitude and mach number 2. total air temp probe - supply air temp to modify altitude and airspeed calc 3. AOA sensor - modifies pitot and static values 4. inertial sys display unit - gives initial present position and heading data 5. mode selector unit - sends mode selection instructions to the ADIRU 6. ADIRU - three accelerometers and three ring laser gyros, which sense motion and angular movement what does EICAS and EFIS stand for? - ANSWERS- engine indicating and crew alerting systems - electronic flight instrument sys boeing and airbus use a different term for the same system. What are they called? what does it do? - ANSWERS- ECAM (airbus) - EICAS (boeing) system displays engine parameters and the various AC sys schematic displays and crew warning, cautions and AC status/advisory messages. is all system data displayed continuously? - ANSWERSno, EICAS system displays certain AC sys and engine parameters on a demand basis in the event of a malfunction, what does the EICAS display? - ANSWERSvital information automatically appears on a screen and the appropriate caution or warning signals are activated what is displayed during normal operation? - ANSWERSminimum engine data, additional sys data may be displayed upon activation during normal flight config, what is the lower screen mainly used for? - ANSWERSusually blank and displays the status of any malfunctioned sys. It acts as a backup display in the event the top screen fails EICAS screens are usually in the center of the instrument panel. What are the lower and upper displays referred to as? - ANSWERSupper is called the main EICAS display and lower is referred to as the auxiliary display what are two variations of the basic EFIS - ANSWERSEICAS and ECAM whats the difference between EFIS and EICAS/ECAM? - ANSWERSEFIS is used to display flight data. ECAM/EICAS are used to display various system parameters (engine ratio, rpm, EGT). Hydraulic pressure and electrical sys parameter are optional to the pilot in EICAS, what are the four different alert levels? - ANSWERSLevel A: warning, red, MOST IMPORTANT. require immediate attention and immediate action (depressurization or engine fire). Aural and visual annunciators Level B: caution, amber, different sound and annunciation. immediate crew awareness and future action Level C: Advisory, light blue, immediate crew awareness and possible future action Level D: memos, white, crew reminders. there are three different modes of displaying EICAS, what are they? - ANSWERS1. primary - shows on main display during normal OP, on upper screen 2. Secondary - at power up, the lower screen automatically shows the secondary format. show engine parameters 3. Compact - used when one display is inactive or being used to show maintenance pages can be displayed on either main or aux screens. what does the EICAS computer consist of? - ANSWERStwo colour display units, two computers, and two control panels. Cancel/recall switch to interact with msg. master caution light on CAP and FO glaresheild only one computer is used at a time for both displays what can the lower DU display? - ANSWERS- engine secondary parameter - APU - Pneumatic - Fuel - FC - AC what components are involved in the ECAM system? - ANSWERS- DU Display - either cathode ray tubes or LCD - System data acquistion concentrators - LVDTs, analog pressure sensors to measure assigned parameters. converts analog to digital signals - display management computers - request digital video and formats on the various DU as requested. - flight Warning computer - controls the warning msgs displayed. how many screens are typically used to eliminate electromechanical instruments ? - ANSWERSup to 6 what is a PFD? - ANSWERSPrimary Flight display. - comprised of E ADI and E HSI - two displays integrated into one - instrument which integrates and depicts all info, on a single display, that was presented on a number of electromechanical instru. what does PFD on modern SC display? - ANSWERS- airspeed - heading - FD commands - time critical annunciation - attitude - vert speed - landing - altitude -flight mode - radio altitude what is displayed on the EHSI or ND - ANSWERS- heading - true airspeed - weather radar - VOR/ADF - VOR deviation - LOC and G/S deviation - Track - wind - TCAS data - Ground speed - route -enhanced GPWS data what are the 3 display modes for ND? - ANSWERS- failure - ARC - plan what do the different colours mean on the ND? - ANSWERS- green (G) - dynamic conditions - white (W) - present status, range scales - magenta (M) - command info, pointers and symbols - cyan (C) - non-active or background info - amber (A) - cautions, faults and flags - red (R) - warnings