Vayudoot Aviation

1. How does the FMS calculate groundspeed?

Input of heading from either the IRS or gyro compass, TAS from ADC and wind velocity from selected metrological data

Input from DME with change of range integrated with respect to time

Input from IRS

Input from ADC of TAS and wind velocity

2. What do you call a system of gyros and accelerometers that is fixed to the aircraft?

Strapdown

Fixed

Stabilised

Laser

3. The principle of 'Schuler Tuning' as applied to the operation of Inertial Navigation Systems/Inertial Reference Systems is applicable to

Only to 'strapdown' laser gyro systems.

Both gyro-stabilised platform and strapdown systems.

Only gyro-stabilised systems

Both gyro-stabilised and laser gyro systems but only when operating in the non 'strapdown' mode.

4. In a ring laser gyro, the purpose of the dither motor is to

Stabilise the laser frequencies

Overcome laser lock

Enhance the accuracy of the gyro at all rotational rates

Compensate for transport wander

5. What output is calculated by double integration of output from the east/west accelerometer of an inertial navigation system (INS) when the system is engaged in the NAV mode?

Distance east/west

Distance north/south

Vehicle longitude

Velocity east/west

6. How does the FMS calculate groundspeed?

Input of heading from either the IRS or gyro compass, TAS from ADC and wind velocity from selected metrological data

Input from IRS

Input from DME with change of range integrated with respect to time

Input from ADC of TAS and wind velocity

7. In order to maintain an accurate vertical using a pendulous system, an aircraft inertial platform incorporates a device?

Without damping and a period of 84.4 SEC

With damping and a period of 84.4 SEC

Without damping and a period of 84.4 MIN

With damping and a period of 84.4 MIN

8. On a triple-fit IRS system, present positions on the CDU?

Will only differ if one IRS has been decoupled due to a detected malfunction.

Will not differ as the information is averaged

Will only differ if an Initial input error of aircraft position has been made

Are likely to differ as the information comes from different sources

9. When the Boeing B737-400 FMS is being initialized prior to flight, the system?

Rejects initial latitude error, but it will accept longitude error

Rejects initial longitude error, but it will accept latitude error

Cannot detect input errors, and accepts whatever is put in

Rejects initial latitude or longitude error

10. In an Inertial Navigation System(INS), the output of the first stage North/South integrator is?

Velocity along the local meridian

Groundspeed

Change of latitude

Latitude

11. Gyro drift occurs when the spin axis moves in the?

Horizontal and vertical

Neither, because its definition is not related to these axes

Vertical

Horizontal

12. What are the positions (in the order left to right) on the Boeing 737-400 IRS Mode Selector Unit (MSU)?

OFF STBY NAV ATT

OFF STBY ATT NAV

OFF STBY ALIGN NAV

OFF ALIGN NAV ATT

13. What is the highest priority and lowest priority, message produced by the CDU of the B737-400 EFIS?

Warning and Advisory

Urgent and Routine

Caution and Advisory

Warning and Caution

14. An IRS differs from an INS in that it?

Does not need to correct for coriolis and central acceleration

Has a shorter spin-up time and suffers from laser lock

Does not experience Schuler errors as accelerometers are strapped down

Has a longer spin-up time and is not affected by vertical accelerations due to gravity

15. When initial position is put into a B737-400 FMS, the system?

Rejects initial latitude error, but it will accept longitude error

Rejects initial latitude or longitude error

Cannot detect input errors, and accepts whatever is put in

Rejects initial longitude error, but it will accept latitude error

16. What do you call a system of gyros and accelerometers that is fixed to the aircraft?

Strapdown

Laser

Stabilised

Fixed

17. If an IRS loses its position mid-flight it must?

Be turned OFF

Not be used in NAV mode

Be selected to ALIGN and then to NAV

Have a new position inserted

18.
Which EFIS symbol below represents the selected course?

D

B

A

C

19. Some Inertial reference and navigation systems are known as "strapdown". This means that?

The gyroscopes and accelerometers become part of the unit's fixture to the aircraft structure

The gyros are stabilised but the accelerometers are fixed to the aircraft structure

The accelerometers are fixed to the aircraft structure but the gyros are stabilised

The indicator units are strapped to the aircraft structure

20. What is the function of the MCDUs in the B737-400Flight Management System when carrying out preflight checks?

Manually initialise the IRSs,FMC and Authorities with dispatch Information

Manually initialise the IRSs and FMC with dispatch information

Automatically initialise the IRSs and FMC with dispatch information

Manually initialise the Flight Director System and FMC with dispatch information

21. If t is the time since selecting the MSU from ALIGN to NAV the azimuth gyro heading error caused by drift rate of an INS/IRS azimuth gyro is?

Proportional to t/2

Proportional to the square root of t

Proportional to t

Sinusoidal

22. The latest point at which an INS or IRS may be selected to NAV mode is?

On operation of TOGA switch when opening the throttles for the take-off

At the holding point

After passengers and freight are aboard

Immediately prior to push back or taxi from the gate

23. From what source is the FMC aircraft position determined by radio navigation in the Boeing 737-400 aircraft derived?

VOR/DME

DME/ADF

DME/DME

VOR/VOR

24. Gyro - compassing in an INS?

d. Is possible in flight as he gyros cannot differentiate between acceleration due to aircraft movement and Initial alignment error.

It is not possible in flight because the gyros cannot differentiate between acceleration due to aircraft movement and initial alignment errors.

Is possible in flight as the gyros can differentiate between acceleration due to aircraft movement and initial alignment errors.

Is not possible in flight as the gyros can differentiate between acceleration due to aircraft movement and Initial alignment errors.

25. What do you call a system of gyros and accelerometers that is fixed to the aircraft?

Strapdown

Laser

Fixed

Stabilised

26. The dither motor in a ring laser gyro sis used to?

Enhance the accuracy of the gyro at all rotational rates

Overcome laser lock

Stabilise the laser frequencies

Compensation for transport wander

27. The sensors of an INS measure?

Velocity

Acceleration

TAS

Position

28. In a laser reference system(IRS), as compared to a gyro reference system (INS)

The accelerometers are strapped down but the platform is gyro stabilised

The platform is strapped down but the accelerometers are gyro-stabilised

Accelerometers and platform are both gyro-stabilised

Accelerometers and platform are both strapped down

29. In an Inertial Navigation System(INS), Ground Speed (GS) is calculated?

From TAS and WN from RNAV data

By integrating measured acceleration

By integrating gyro precession in N/S and E/W directions respectively

From TAS and WN from Air Data Computer (ADC)

30. How is the FMC position produced?

The average of the IRS position

Computer generated from the radio navigation positions

Computer generated from the IRS and radio navigation positions

Half way between the IRS and radio navigation positions

31. FMC aircraft position determined by radio navigation is derived on the B737-400 FMS from?

DME/ADF

VOR/DME

VOR/VOR

DME/DME

32. On the IRS, selection of ATT mode gives attitude?

Only

And heading

Altitude and heading

Heading and groundspeed

33. If an INS temporarily loses its power supply in flight?

It can only be used for attitude reference

It will be usable only in the NASV mode

It will functions normally

It must be switched off for the remainder of the flight

34. Alignment of INS and IRS equipments can take place in which of the following modes?

ALIGN only

ATT and ALIGN

NAV and ALIGN

ALIGN and ATT

35. If an IRS loses its position mid-flight it must?

Be turned OFF

Not be used in NAV mode

Have a new position inserted

Be selected to ALIGN and then to NAV

36. Alignment of INS and IRS equipments can take place in which of the following modes?

NAV and ALIGN

ATT and ALIGN

ALIGN and ATT

ALIGN only

37. The INS CDU mode selection required to display Initial Great Circle track is?

HDG/DA

XTK/TKE

TK/GS

DSRTK/STS

38. In what way does IRS differ from INS?

Does not experience Schuler errors as accelerometers are strapped down.

Does not need to correct for coriolis and central acceleration

Has a shorter spin-up time and suffers from laser lock

Has a longer spin-up time and is not affected by vertical acceleration due to gravity.

39. The functions of the Boeing 737-400 FMS include?

Automatic navigation & manual performance management

Manual navigation & manual performance management

Automatic navigation & automatic performance management

Manual navigation & automatic performance management

40. On an aircraft equipped with a triple-fit IRS system, present positions on the CDU?

Will only differ if an initial input error of aircraft position has been made

Will not differ as the information is averaged

Are likely to differ as the information comes from different sources

Wlli only differ if one IRS has been decoupled due to a detected malfunction

41. What format is used to enter positions into INS systems?

Waypoint names

Hexadecimais

Geographic coordinates

Ranges and bearings

42. An aircraft equipped with an Inertial Navigation System (INS) files with INS 1 coupled with autopilot 1. Both Inertial navigation systems are navigating from waypoint A to B. The inertial systems 'Central Display Units (CDU) show: XTK on INS 1 = 12 L XTK on INS 2 = 0(XTK = cross track) What can be deducted from this information?

At least one of the Inertial navigation systems is drifting

Only Inertial navigation system no. 1 drifting

Only Inertial navigation system No.2 is drifting

The autopilot is unserviceable in NAV mode

43. How long does it take to align an IRS (Laser Ring Gyros)?

10 minutes

1 minute

5 minutes

15 minutes

44. In which IRS mode does gyro-compassing takeplace?

ALIGN

NAV

ON

ATT

45. In an Inertial Navigation system (INS), what is the output of the first stage North/South Integator?

Latitude

Groundspeed

Change of latitude

Velocity along the local meridian

46. In an Inertial Navigation System (INS), Ground Speed (GS) is calculated?

By integrating measured acceleration

By Integrating gyro precession in N/S and E/W directions respectively.

From TAS and WN from Air Data Computer (ADC)

From TAS and WN from RNAV data

47. From what information is the FMC position calculated?

Computer generated from the radio navigation positions

Half way between the IRS and radio navigation positions

Computer generated from the IRS and radio navigation positions

The average of the IRS positions

48. Where and when are the IRS positions updated?

Updating is normally carried out by the crew when over-flying a known position (VOR station or NDB)

Only on the ground during the alignment procedure

During flight IRS positions are automatically updated by the FMC

IRS positions are updated by pressing the 'Take-off/Go-around' button at the start of the take-off roll

49. In what modes is the Weather Radar Display available on EFIS EHSI?

MAP, EXPVOR/ILS, EXP NAV

MAP,PLAN, FULL VOR/ILS

MAP, PLAN, EXP VOR/ILS

MAP, FULLVOR/ILS, FULL NAV

50. In an INS the process of gyro-compassing?

It is not possible in flight because the gyros cannot differentiate between acceleration due to aircraft movement and initial alignment errors

Is possible in flight as the gyros cannot differentiate between acceleration due to aircraft movement and initial alignment errors.

Is possible in flight as the gyros can differentiate between acceleration due to aircraft movement and initial alignment errors.

Is not possible in flight as the gyros can differentiate between acceleration due to aircraft movement and initial alignment errors

Question Bank

Questions for INS/IRS/FMS