RAD 17 – RNAV and FMS – LMS

📄 Detailed Notes ⚡ Cheat Sheet

Results

📄 Notes ⚡ Cheat Sheet

Q1. The accuracy required of a basic area navigation (B-RNAV) system is:

(+/-5 NM on 95% of occasions)

(+/-5 NM on 90% of occasions)

all the time

(+/-5 NM on 75% of occasions)

[+/-5 NM on 95% of occasions] –

Step 1: B-RNAV (Basic RNAV) is defined by RNP-5 standards.

Step 2: RNP-5 requires a track-keeping accuracy of +/-5 NM.

Step 3: Performance must be maintained for at least 95% of the flight time.

Q2. The required accuracy of a precision RNAV (P-RNAV) system is:

1.5 NM standard deviation or better

0.5 NM standard deviation or better

0.25 NM standard deviation or better

1 NM standard deviation or better

[1 NM standard deviation or better] –

Step 1: P-RNAV (Precision RNAV) is defined by RNP-1 standards.

Step 2: The containment value for RNP-1 is 1 NM.

Step 3: This must be met on 95% of occasions (standard deviation of 1 NM).

Q3. Which of the following statements regarding B-RNAV is correct?

B-RNAV can be used up to FL95. Above FL95

B-RNAV is only applicable when flying in TMAs

In case of B-RNAV, RNPI is required

For 95% of the flight time, the track keeping accuracy must not exceed 5 nm

[For 95% of the flight time, the track keeping accuracy must not exceed 5 nm] –

Step 1: Verify the definition of B-RNAV.

Step 2: It is equivalent to RNP-5.

Step 3: RNP-5 signifies a track-keeping accuracy of 5 NM for 95% of the time.

Q4. A basic 2D RNAV system will determine tracking information from:

twin DME

any of the above

VOR/DME

twin VOR

[VOR/DME] –

Step 1: 2D RNAV systems use Rho-Theta (VOR/DME) or Rho-Rho (DME/DME) for positioning.

Step 2: Basic systems typically rely on a single VOR/DME facility to calculate “phantom stations.”

Step 3: DME/DME is generally more accurate, but VOR/DME is the standard basic input.

Q5. The phantom station in a 2D RNAV system may be generated by:

any of the above

twin VOR

twin DME

VOR/DME

[VOR/DME] –

Step 1: A phantom station (waypoint) is created by offsetting a bearing and distance from a ground station.

Step 2: The Course Line Computer (CLC) uses bearing (Theta) and range (Rho) data.

Step 3: Standard VOR/DME provides both components needed for the calculation.

Q6. An aircraft using a basic 2D RNAV system is on a section between WP1 and WP2, a distance of 45 NM. The aircraft is 20 NM from the phantom station, which is 270 deg / 30 NM from the VOR/DME. The aircraft is 15 NM from the VOR/DME. The range read-out will show:

25 NM

15 NM

20 NM

30 NM

[20 NM] –

Step 1: Identify what the range readout displays in RNAV mode.

Step 2: The RNAV computer calculates the distance to the active waypoint (phantom station).

Step 3: The question states the aircraft is 20 NM from the phantom station; therefore, the range readout is 20 NM.

Q7. An aircraft, using a 2D RNAV computer, is 12 NM from the phantom station, 25 NM from the VOR/DME designating the phantom station and the phantom station is 35 NM from the VOR/DME. The range read-out in the aircraft will be:

25 NM slant range

35 NM

12 NM

25 NM plan range

[12 NM] –

Step 1: In RNAV mode, distance is displayed to the waypoint, not the facility.

Step 2: The waypoint is the “phantom station.”

Step 3: Given distance to phantom station is 12 NM, the display shows 12 NM.

Q8. What function does the course line computer perform?

Uses VOR/DME information to direct the aircraft along a specified track

Uses VOR/DME information to direct the aircraft to the facility

Uses VOR/DME information to determine track and distance to a waypoint

Converts VOR/DME information into HSI directions to maintain the planned track

[Uses VOR/DME information to determine track and distance to a waypoint] –

Step 1: The Course Line Computer (CLC) is the brain of basic RNAV.

Step 2: It shifts the VOR/DME station to a waypoint location.

Step 3: It continuously computes the range and bearing from the aircraft to this waypoint.

Q9. The FMC position will be at its most inaccurate:

on final approach

at TOD

at TOC

on take-off

[on TOD] –

1: The FMC begins its navigation sequence with initial position entry.
2: Before radio updates or high-speed GPS/DME-DME filtering become stable after lift-off, the position relies heavily on the initial IRS alignment.
3: Drift and initial error are most prominent during the departure/take-off phase before external updates refine the Kalman filter.
Most inaccurate at — TOD
Most Accurate – after Update on threshold.

Q10. The IRS position can be updated:

on the ground only

at designated positions en route and on the ground

at selected waypoints and on the ground

on the ground and overhead VOR/DME

[on the ground only] –

Step 1: Inertial Reference Systems (IRS) require a stationary period for alignment.

Step 2: Once in NAV mode, the internal IRS position itself cannot be “updated” or reset to a new coordinate while in flight.

Step 3: While the FMC uses external aids to calculate a “FMC Position,” the raw IRS coordinates remain independent until the next ground alignment.

Q11. The correct format for the input of position 5000N 00527E to the CDU is:

N50E00527

N5000.0E00527.0

N5000E00527

5000.0N00527.0E

[N5000.0E00527.0] –

Step 1: CDU inputs require specific alphanumeric precision.

Step 2: Standard format includes Degrees, Minutes, and Decimal Minutes (0.1 accuracy).

Step 3: Format is Hemisphere (N/S) + Lat + Hemisphere (E/W) + Long.

Q12. The FMC navigational database can be accessed by the pilots:

to change the information to meet the sector requirements

to read information only

to change information between the 28-day updates

to update the database

[to read information only] –

Step 1: The AIRAC database is a read-only protected file for pilots.

Step 2: Pilots cannot modify existing stored coordinates of VORs or airways.

Step 3: They can only extract/read data to build a flight plan.

Q13. The period of validity of the navigational database is:

1 month

28 days

determined by national authority (28-91 days)

91 days

[28 days] –

Step 1: Aeronautical Information Regulation and Control (AIRAC) cycles are standardized.

Step 2: Each cycle is exactly 28 days.

Step 3: FMS databases must be updated every 28 days to remain valid.

Q14. The database of an FMS (Flight Management System) is organized in such a way that the pilot can:

Insert navigation data between two updates/waypoints

Read and write at any time in database

Only read the database

Can modify the database every 28 days

[Insert navigation data between two updates/waypoints] –

Step 1: Pilots cannot edit the master Nav Database.

Step 2: However, they can insert “pilot-defined” waypoints or temporary route data for the current flight.

Step 3: This allows flexibility without compromising the integrity of the official AIRAC data.

Q15. The position used by the FMC in the B737-400 is:

taken from the selected IRS, smoothed by Kalman filtering and updated to the external reference

an average of the two IRS positions, smoothed by the Kalman filtering process

generated from the external reference and updated by the IRS as part of the Kalman filtering process

an average of the two IRS positions

Correct Answer —

Taken from the selected IRS, smoothed by Kalman filtering and updated to the external reference

Q16. Concerning FMC operation, which of the following is true:

the FMC combines the short-term accuracy of the IRS with the short-term accuracy of the external reference

the FMC combines the long-term accuracy of the IRS with the long-term accuracy of the external reference

the FMC combines the long-term accuracy of the IRS with the short-term accuracy of the external reference

the FMC combines the short-term accuracy of the IRS with the long-term accuracy of the external reference

[the FMC combines the short-term accuracy of the IRS with the long-term accuracy of the external reference] –

Step 1: Evaluate IRS characteristics: Excellent short-term accuracy (no noise) but drifts over time (poor long-term).

Step 2: Evaluate Radio/GPS: No drift over time (excellent long-term) but has signal noise/jitter (poor short-term).

Step 3: FMC combines them to get the best of both.

Q17. The Flight Management Computer (FMC) position is:

The computed position based on a number of sources (IRS, Radio, ILS, GPS etc)

The same as that given on the No. 1 IRS

Another source of aircraft position; it is independent of other position sources

The actual position of the aircraft at any point in time

[The computed position based on a number of sources (IRS, Radio, ILS, GPS etc)] –

Step 1: The FMC is a multi-sensor integrator.

Step 2: It does not rely on a single source.

Step 3: It computes a weighted average of all available sensors.

Q18. In an RNAV system which combination of external reference will give the most accurate position?

GPS/rho

Rho/Rho

Rho/theta

GPS/theta

[Rho/Rho] –

Step 1: Rho/Rho refers to DME/DME.

Step 2: Fixes based on two distances (intersecting arcs) are more accurate than those using a bearing (Theta) which is subject to angular error.

Step 3: Note: While GPS is technically more accurate, in the context of standard RNAV ground-aid referencing, DME/DME (Rho/Rho) is the gold standard.

Q19. Which of the following combinations is likely to result in the most accurate Area Navigation (RNAV) fixes?

DME/DME

VOR/VOR

VOR/DME

NDB/VOR

[DME/DME] –

Step 1: Compare ground-based navigation errors.

Step 2: VOR has a significant angular error that increases with distance.

Step 3: DME distance error is constant and very small; intersecting two DME arcs (Rho/Rho) provides the highest ground-based accuracy.

Q20. In an RNAV system the DME is tuned:

by automatically selecting the nearest suitable DME

automatically by taking pilot's DME selection

by what is selected on the pilots DME and hence is tuned manually

by selecting DMEs to give suitable angle of cut to get a fix automatically

[by selecting DMEs to give suitable angle of cut to get a fix automatically] –

Step 1: Modern FMC/RNAV systems have “auto-tuning” capability.

Step 2: The system scans the database for DMEs.

Step 3: It automatically tunes the facilities that provide the best geometry (angle of cut) for an accurate position fix.

Q21. Which positions can be input to the FMC using a maximum of 5 alphanumeric?

SIDS & STARS and latitude and longitude

Navigation facilities, reporting points and airways designators

Latitude and longitude, reporting points and airways designators

SIDS & STARS, reporting points and airways designators

[Navigation facilities, reporting points and airways designators] –

Step 1: FMC/CDU data fields have character limits.

Step 2: Standard ICAO identifiers for VORs (3 letters), fixes (5 letters), and airways (e.g., J105) fit within a 5-character limit.

Step 3: Lat/Long requires more characters (e.g., N5000E00527).

Q22. Above latitudes of 84 deg a twin FMS/triple IRS system will go to de-coupled operations. The reason for this is:

because the magnetic variation changes rapidly in high latitudes

to prevent error messages as the IRS longitudes show large differences

to ease the pilot's workload

to improve the system accuracy

[to prevent error messages as the IRS longitudes show large differences] –

Step 1: Near the poles, meridians of longitude converge.

Step 2: A small physical distance results in a massive change in longitude degrees.

Step 3: To avoid system disagreements and nuisance alerts due to “longitude rapid-change,” the systems operate independently (de-coupled).

Q23. The navigational function of the horizontal situation indicator (HSI) in relation to area navigation systems is?

The indication of the cross track distance (XTK)

The indication of the wind component

The indication of the cross track angle error (TKE)

The indication of the RNP

[The indication of the cross track distance (XTK)] –

Step 1: Standard VOR navigation shows angular deviation (dots per degree).

Step 2: RNAV mode changes the HSI logic.

Step 3: In RNAV, the deviation bar shows linear distance from track (Cross Track Distance) in NM.

Q24. Which component of an Area Navigation System displays the Cross Track Distance?

Navigation Display

Attitude Display

DME Indicator

Radio Magnetic Indicator

[Navigation Display] –

Step 1: Cross Track Distance (XTK) is a key lateral navigation parameter.

Step 2: It is displayed visually on the EFIS Navigation Display (ND).

Step 3: It shows how many miles the aircraft is left or right of the programmed track.

Q25. In an RNAV approach phase with a two-dot lateral deviation HSI display, a one-dot deviation from track would represent:

5 NM

0.5 NM.

0.5 deg.

5 deg.

[0.5 NM.] –

Step 1: RNAV HSI sensitivity increases during the approach phase.

Step 2: Full-scale (2 dots) typically represents 1.0 NM in the terminal/approach environment.

Step 3: Therefore, a one-dot deviation equals half the full-scale value (0.5 NM).

Q26. Which statement about RNAV is correct?

In general RNAV routes coincide with standard route in order to make optimum use of the available VOR/DME stations

RNAV routes are only used in terminal areas in order to make more efficient use of the approach and landing facilities of an airport

All waypoints of RNAV routes are called phantom stations

A method of navigation which permits aircraft operation on any desired flight path

[A method of navigation which permits aircraft operation on any desired flight path] –

Step 1: RNAV is defined by the ability to fly point-to-point.

Step 2: It removes the requirement to fly directly over ground stations.

Step 3: This allows for “any desired flight path” within the limits of the navigation aid coverage.

Q27. One of the benefits of RNAV is?

RNAV allows to obtain ATC clearance by HF radio without the requirement to establish any radio contact

RNAV allows aircraft to fly at RNAV flight levels with a 500 ft separation

RNAV allows pilots to manage horizontal and vertical separation with other aircraft without obtaining ATC clearance

RNAV allows aircraft to take a more direct flight path without requiring to fly over ground based facilities

[RNAV allows aircraft to take a more direct flight path without requiring to fly over ground based facilities] –

Step 1: Ground-aid based navigation (VOR/NDB) creates “dog-leg” routes.

Step 2: RNAV allows straight-line (Great Circle) tracks between waypoints.

Step 3: This results in shorter, more direct flight paths and fuel savings.

Q28. The indications from a basic RNAV are behaving erratically. The reason is likely to be:

the aircraft is below line of sight range of the reference VOR/DME

the aircraft is outside the DOC of the reference VOR/DME

the aircraft is in the cone of confusion of the phantom station

the aircraft is in the cone of confusion of the reference VOR

[the aircraft is outside the DOC of the reference VOR/DME] –

Step 1: RNAV accuracy depends on the quality of the signal from the “Reference Station.”

Step 2: The Designated Operational Coverage (DOC) ensures signal integrity and lack of interference.

Step 3: Operating outside the DOC leads to unstable data and erratic computer output.

Q29. ICAO Annex 11 defines Area Navigation (RNAV) as a method of navigation which permits aircraft operation on any desired flight path:

Within the coverage of station-referenced navigation aids or within the limits of the capability of self-contained aids, or a combination of these

Within the coverage of station-referenced navigation aids provided that it is equipped with a minimum of one serviceable self-contained navigation aid

Outside the coverage of station-referenced navigation aids provided that it is equipped with a minimum of one serviceable self-contained navigation aid

Outside the coverage of station-referenced navigation aids provided that it is equipped with a minimum of two serviceable self-contained navigation aids

[Within the coverage of station-referenced navigation aids or within the limits of the capability of self-contained aids, or a combination of these] –

Step 1: Formal ICAO definition.

Step 2: RNAV is not limited to ground-based aids alone.

Step 3: It encompasses both station-referenced (VOR/DME) and self-contained (IRS/GNSS) systems.

Q30. The IRS is a self-contained system because?

It operates independently of navigational aids outside the aircraft

The system generates a warning in case of a failure

The calculation of the position does not require any software

It operates off its own power supply

[It operates independently of navigational aids outside the aircraft] –

Step 1: Define “self-contained.”

Step 2: It means the system does not need external radio signals (VOR/DME/GPS).

Step 3: IRS uses internal accelerometers and gyroscopes to calculate position relative to its starting point.

Q31. A 3-dimensional RNAV system has capability in?

The horizontal plane and the cruise management system

The horizontal plane, the vertical plane, and the timing function

The horizontal plane and the speed management system

The horizontal plane and the vertical plane

[The horizontal plane and the vertical plane] –

Step 1: Dimensions of RNAV: 2D is Lat/Long.

Step 2: 3D adds the vertical dimension (Altitude).

Step 3: Therefore, 3D RNAV manages path in the horizontal and vertical planes.

Q32. What is true about the FMC database?

The navigation database contains the company's cost index strategy

The data can be customized for the specific airline operations

The performance database contains aeronautical information for the planned area of operations of the aircraft

The data includes SIDS, STARs, and runway approaches

[The data includes SIDS, STARs, and runway approaches] –

Step 1: The FMC has two primary databases: Navigation and Performance.

Step 2: The Navigation database stores waypoints, airways, and procedures.

Step 3: SIDs, STARs, and approaches are part of this aeronautical information set.

Q33. Concerning FMC databases?

The navigation database may be customized for the specific airline operations

Company databases and FMC databases can not be used at the same time

Only the performance database may be customized by the company

Only the navigation database may be customized for the company's cost index strategy

[The navigation database may be customized for the specific airline operations] –

Step 1: Airlines often have specific needs (company routes/private fixes).

Step 2: The navigation database can be customized to include these unique identifiers.

Step 3: This allows the FMS to match the specific routes flown by the airline.

Q34. The sequence of displays accessed on initialization is:

IDENT, RTE, POS INIT

POS INIT, RTE, IDENT

POS INIT, IDENT, RTE

IDENT, POS INIT, RTE

[IDENT, POS INIT, RTE] –

Step 1: Standard FMC startup flow.

Step 2: IDENT (Verify software/engine/nav data version).

Step 3: POS INIT (Enter starting coordinates).

Step 4: RTE (Enter route of flight).

Q35. In which of the following cases would ETOs and ETA at destination calculated by the Flight Management Computer (FMC) be correct?

When the FMC positions and GS are accurate

When the FMC computes each ETO and ETA using the correct GS

When the actual winds match the forecast winds, and the actual cruising Mach number is equal to the FMC calculated Mach number

When the ETOs and ETA are based on the forecast winds calculated from the actual take-off time

[When the actual winds match the forecast winds, and the actual cruising Mach number is equal to the FMC calculated Mach number] –

Step 1: FMC ETA is a predictive calculation.

Step 2: Predictive accuracy depends on the delta between “Forecast” and “Actual” data.

Step 3: If wind and speed match the values used for calculation, the ETA will be correct.

Q36. Which EHSI modes cannot show AWR information?

PLAN, MAP and EXP VOR/ILS

MAP and PLAN

PLAN and FULL VOR/ILS

FULL VOR/ILS and MAP

[PLAN and FULL VOR/ILS] –

Step 1: AWR (Airborne Weather Radar) requires a moving scan overlay.

Step 2: PLAN mode is a static map (North-up) used for route review.

Step 3: FULL VOR/ILS modes use a traditional compass rose that does not support the radar sweep overlay.

Q37. The track-line on the Electronic Horizontal Situation Indicator (EHSI) or Navigation Display of an Electronic Flight Instrument System:

Represents the track of the aircraft over the ground. When it coincides with the desired track, wind influence is compensated for

Corresponds to the calculated IRS TH and is correct during turns

Indicates to the pilot that a manually selected heading is being flown

Indicates that the pilot has made a manual track selection

[Represents the track of the aircraft over the ground. When it coincides with the desired track, wind influence is compensated for] –

Step 1: The track line (green or white line) shows actual path over the ground.

Step 2: Desired track is the route line.

Step 3: By putting the track line over the desired track, the pilot has successfully corrected for drift (WCA).

Q38. The operation of a 2D RNAV system may be seriously downgraded:

because the pilot cannot verify the correct frequency has been selected

because the computer cannot determine if the heading and altitude input are in error

because the computer cannot determine if the aircraft is within the DOC of the programmed facilities

if the selected navigation facility is in excess of about 70 NM

[because the computer cannot determine if the aircraft is within the DOC of the programmed facilities] –

Step 1: 2D RNAV relies purely on radio signals.

Step 2: The computer blindly processes whatever signal it receives on the tuned frequency.

Step 3: If the aircraft is outside the DOC, it may receive co-channel interference or unstable signals, which the computer cannot filter out.

Q39. In order that a waypoint designated by a VOR can be used by an RNAV system:

the VOR need not be in range when input or used

the VOR must be identified by the pilot

the VOR need not be in range when input but must be when used

the VOR must be within range when the waypoint is input

[the VOR need not be in range when input but must be when used] –

Step 1: Pre-flight data entry.

Step 2: You can program any waypoint into the computer regardless of where you are.

Step 3: However, the system cannot navigate to it (basic RNAV) until the aircraft is within signal range of the reference station.

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Results

Q1. The accuracy required of a basic area navigation (B-RNAV) system is:

Q2. The required accuracy of a precision RNAV (P-RNAV) system is:

Q3. Which of the following statements regarding B-RNAV is correct?

Q4. A basic 2D RNAV system will determine tracking information from:

Q5. The phantom station in a 2D RNAV system may be generated by:

Q6. An aircraft using a basic 2D RNAV system is on a section between WP1 and WP2, a distance of 45 NM. The aircraft is 20 NM from the phantom station, which is 270 deg / 30 NM from the VOR/DME. The aircraft is 15 NM from the VOR/DME. The range read-out will show:

Q7. An aircraft, using a 2D RNAV computer, is 12 NM from the phantom station, 25 NM from the VOR/DME designating the phantom station and the phantom station is 35 NM from the VOR/DME. The range read-out in the aircraft will be:

Q8. What function does the course line computer perform?

Q9. The FMC position will be at its most inaccurate:

Q10. The IRS position can be updated:

Q11. The correct format for the input of position 5000N 00527E to the CDU is:

Q12. The FMC navigational database can be accessed by the pilots:

Q13. The period of validity of the navigational database is:

Q14. The database of an FMS (Flight Management System) is organized in such a way that the pilot can:

Q15. The position used by the FMC in the B737-400 is:

Q16. Concerning FMC operation, which of the following is true:

Q17. The Flight Management Computer (FMC) position is:

Q18. In an RNAV system which combination of external reference will give the most accurate position?

Q19. Which of the following combinations is likely to result in the most accurate Area Navigation (RNAV) fixes?

Q20. In an RNAV system the DME is tuned:

Q21. Which positions can be input to the FMC using a maximum of 5 alphanumeric?

Q22. Above latitudes of 84 deg a twin FMS/triple IRS system will go to de-coupled operations. The reason for this is:

Q23. The navigational function of the horizontal situation indicator (HSI) in relation to area navigation systems is?

Q24. Which component of an Area Navigation System displays the Cross Track Distance?

Q25. In an RNAV approach phase with a two-dot lateral deviation HSI display, a one-dot deviation from track would represent:

Q26. Which statement about RNAV is correct?

Q27. One of the benefits of RNAV is?

Q28. The indications from a basic RNAV are behaving erratically. The reason is likely to be:

Q29. ICAO Annex 11 defines Area Navigation (RNAV) as a method of navigation which permits aircraft operation on any desired flight path:

Q30. The IRS is a self-contained system because?

Q31. A 3-dimensional RNAV system has capability in?

Q32. What is true about the FMC database?

Q33. Concerning FMC databases?

Q34. The sequence of displays accessed on initialization is:

Q35. In which of the following cases would ETOs and ETA at destination calculated by the Flight Management Computer (FMC) be correct?

Q36. Which EHSI modes cannot show AWR information?

Q37. The track-line on the Electronic Horizontal Situation Indicator (EHSI) or Navigation Display of an Electronic Flight Instrument System:

Q38. The operation of a 2D RNAV system may be seriously downgraded:

Q39. In order that a waypoint designated by a VOR can be used by an RNAV system:

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