POF – 10 Stability Part 3 ( Combined, Directional, Duch Roll & Dynamic ) – LMS

Results

Q1. Which aeroplane behaviour will be corrected by a yaw damper?

Spiral dive

Tuck under

Dutch roll

Buffeting

Q2. What is the recommended action following failure of the yaw damper(s) of a jet aeroplane, flying at normal cruise altitude and speed prior to encountering Dutch roll problems?

Manually recover any subsequent Dutch Roll motion using rudder

Increase Mach number to improve aerodynamic damping of any subsequent Dutch Roll motion

No action is required

Reduce altitude and Mach number

Q3. Which moments or motions interact in a dutch roll?

Rolling and yawing

Pitching and yawing

Pitching and rolling

Pitching and adverse yaw

Q4. When considering the relationship between lateral static stability and directional stability:

dominant directional static stability gives an increased tendency for dutch roll

dominant lateral static stability gives an increased tendency for spiral instability

dominant lateral static stability gives an increased tendency for dutch roll

they are mutually independent and have no effect on each other

Q5. Which of these statements are correct or incorrect regarding a sideslip, with the relative airflow coming from the left, on an aeroplane that exhibits both directional and lateral stability?I. The initial tendency of the nose of the aeroplane is to move to the rightII. The initial tendency of the right wing is to move down

1 is incorrect; 2 is incorrect

1 is correct; 2 is incorrect

1 is incorrect; 2 is correct

1 is correct; 2 is correct

Q6. Which of these statements are correct or incorrect regarding a sideslip, with the relative airflow coming from the right, on an aeroplane that exhibits both directional and lateral stability?I. The initial tendency of the nose of the aeroplane is to move to the leftII. The initial tendency of the right wing is to move down

1 is incorrect; 2 is correct

1 is correct; 2 is incorrect

1 is correct; 2 is correct

1 is incorrect; 2 is incorrect

Q7. Which of these statements are correct or incorrect regarding a sideslip, with the relative airflow coming from the left, on an aeroplane that exhibits both directional and lateral stability?I. The initial tendency of the nose of the aeroplane is to move to the rightII. The initial tendency of the right wing is to move down

1 is correct; 2 is correct

1 is correct; 2 is incorrect

1 is incorrect; 2 is incorrect

1 is incorrect; 2 is correct

Q8. Which of these statements are correct or incorrect regarding a sideslip, with the relative airflow commg from the right, on an aeroplane that exhibits both directional and lateral stability?I. The initial tendency of the nose of the aeroplane is to move to the leftII. The initial tendency of the right wing is to move down

1 is correct; 2 is correct

1 is correct; 2 is incorrect

1 is incorrect; 2 is correct

1 is incorrect; 2 is incorrect

Q9. Which of these statements are correct or incorrect regarding a sideslip, with the relative airflow coming from the left, on an aeroplane that exhibits both directional and lateral stability?I. The initial tendency of the nose of the aeroplane is to move to the rightII. The initial tendency of the right wing is to move down

1 is correct; 2 is incorrect

1 is incorrect; 2 is incorrect

1 is incorrect; 2 is correct

1 is correct; 2 is correct

Q10. Which of these statements are correct or incorrect regarding a sideslip, with the relative airflow coming from the right, on an aeroplane that exhibits both directional and lateral stability?I. The initial tendency of the nose of the aeroplane is to move to the leftII. The initial tendency of the right wing is to move down

1 is incorrect; 2 is incorrect

1 is correct; 2 is correct

1 is incorrect; 2 is correct

1 is correct; 2 is incorrect

Q11. Winch of these statements are correct or incorrect regarding a sideslip, with the relative airflow coming from the right, on an aeroplane that exhibits both directional and lateral stability?I. The initial tendency of the nose of the aeroplane is to move to the leftII. The initial tendency of the right wing is to move down

1 is incorrect; 2 is incorrect

1 is correct; 2 is correct

1 is correct; 2 is incorrect

1 is incorrect; 2 is correct

Q12. Which of the following gives an unstable contribution in sideslip?

Wing sweep

Flap extension

Dihedral

High wing

Q13. An example of a combined lateral and directional aperiodic motion is a:

Dutch roll

Phugoid

Short period oscillation

Spiral dive

Q14. Sensitivity for spiral dive will occur when:

The static directional stability is positive and the static lateral stability is relatively weak

The Dutch Roll tendency is too strongly suppressed by the yaw damper

The static lateral and directional stability are both negative

The static directional stability is negative and the static lateral stability is positive

Q15. Which of the following statements about static lateral and directional stability is correct?

The effects of static lateral and static directional stability are completely independent of each other because they take place about different axis

An aeroplane with an excessive static directional stability in relation to its static lateral stability, will be prone to spiral dive (spiral instability)

An aeroplane with an excessive static directional stability in relation to its static lateral stability, will be prone to Dutch roll

Static directional stability can be increased by installing more powerful engines

Q16. Sensitivity for spiral dive will occur when:

the static directional stability is negative and the static lateral stability is positive

the static directional stability is positive and the static lateral stability is relatively weak

the static lateral and directional stability are both negative

the dutch roll tendency is too strongly suppressed by the yaw damper

Q17. When pulling out of a dive the angle of attack:

increases

decreases

remains the same

cannot be increased at all due to structural considerations

Q18. The effect of a ventral fin on the static stability of an aeroplane is as follows: (1=longitudinal, 2=lateral, 3=directional)

1: no effect, 2: positive, 3: negative

1: positive, 2: negative, 3: negative

1: negative, 2: positive, 3: positive

1: no effect, 2: negative, 3: positive

Q19. Increasing the size of the fin:

reduces directional stability

reduces lateral stability

increases longitudinal stability and directional control

increases the size of the keel surface behind the CG, giving increased directional stability

Q20. An aeroplane has static directional stability; in a sideslip to the right, initially the:

nose of the aeroplane tends to move to the left

right wing tends to go down

nose of the aeroplane will remain in the same direction

nose of the aeroplane tends to move to the right

Q21. An aeroplane has static directional stability if, when in a sideslip with the relative airflow coming from the left, initially the:

Right wing tends to go down

Nose of the aeroplane tends to yaw right

Nose of the aeroplane tends to yaw left

Nose of the aeroplane does not move

Q22. The primary function of the fin is to give:

lateral stability – about the longitudinal axis

directional stability – about the normal axis

directional stability – about the longitudinal axis

directional stability – about the lateral axis

Q23. The effect of a positive wing sweep on static directional stability is as follows:

negative dihedral effect

no effect

destabilising dihedral effect

stabilising effect

Q24. The contribution of wing sweep back to static directional stability is:

Positive

Positive or negative, depending on sweepback angle

Zero

Negative

Q25. The effect of a wing with sweepback on static directional stability is as follows:

No effect

Stabilizing effect

Destabilizing dihedral effect

Negative dihedral effect

Q26. The contribution of swept back wings to static directional stability:

is nil

is negative

is positive

decreases as the sweepback increases

Q27. The effect of a wing with sweepback on static directional stability is as follows:

Destabilising dihedral effect

No effect

Stabilising effect

Negative dihedral effect

Q28. Which of the following provides a positive contribution to static directional stability?

A dorsal fin

A forward swept wing

A low wing as compared with a high wing

Moving the centre of gravity aft

Q29. The contribution of swept back wings to static directional stability :

Is positive

Is nil

Decreases as the sweepback increases

Is negative

Q30. The purpose of the dorsal fin is to:

Maintain static directional stability at large sideslip angles

Provide pitch and yaw control

Reduce tendency for spiral instability

Stabilize forebody vortices

Q31. Static directional stability is mainly provided by:

The fin

The elevator

Wing anhedral

Wing dihedral

Q32. An example of a combined lateral and directional periodic motion is a:

Spiral dive

Short period oscillation

Phugoid

Dutch Roll

Q33. If the static lateral stability of an aeroplane is increased, whilst its static directional stability remains constant:

its sensitivity to Dutch roll increases

its spiral stability decreases

turning flight becomes more difficult

the nose-down pitching moment in a turn increases

Q34. An aeroplane is sensitive to Dutch Roll when:

Static lateral stability is much less pronounced than static directional stability

Static lateral stability is much more pronounced than static directional stability

Static stability is less pronounced than dynamic stability

An aeroplane has anhedral

Q35. The tendency to Dutch Roll increases when:

The static directional stability increases

The anhedral increases

The static lateral stability increases

The CG moves forward

Q36. Which one of the following systems suppresses the tendency to Dutch roll?

Rudder limiter

Yaw damper

Roll spoilers

Spoiler mixer

Q37. What will increase the sensitivity to Dutch Roll?

A forward movement of the centre of gravity

An increased anhedral

An increased static lateral stability

An increased static directional stability

Q38. Which of the following increases the tendency for Dutch roll?

increased anhedral

increased keel surface aft of the CG

increased static lateral stability

decreased dihedral

Q39. The tendency for Dutch roll increases with:

increased static directional stability

forward CG position

increased anhedral

increased static lateral stability

Q40. What will increase the tendency to Dutch roll?

an increased static lateral stability

An increased static directional stability

A forward movement of the centre of gravity

An increased anhedral

Q41. Dutch roll is a combination of:

pitch and roll

pitch and yaw

yaw and roll

none of the above

Q42. One of the requirements for positive dynamic stability is:

Positive static stability

An effective elevator

A large deflection range of the stabilizer trim

A small CG range

Q43. The short period mode/oscillation is an:

oscillation about the vertical axis

oscillation about the lateral axis

oscillation about the longitudinal axis

unstable movement of the aeroplane, induced by the pilot

Q44. One of the requirements for dynamic stability is:

positive static stability

a large deflection range of the stabilizer trim

a small C.G. range

effective elevator

Q45. A statically unstable aeroplane is:

always dynamically stable

never dynamically stable

sometimes dynamically stable

sometimes dynamically unstable

Q46. An aeroplane that has positive static stability:

is never dynamically stable

is always dynamically stable

can be dynamically stable, neutral or unstable

is always dynamically unstable

Q47. The short-period mode of longitudinal dynamic stability is:

a rapid oscillation about the normal axis

a rapid oscillation about the longitudinal axis

a rapid oscillation about the lateral axis

always induced by the pilot

Q48. Which statement is correct?

The phugoid should always be heavily damped

The short period oscillation should always be heavily damped

When the phugoid is slightly unstable, an aeroplane becomes uncontrollable

A slightly unstable short period oscillation is no problem for an aeroplane

Q49. Which of the following statements is correct?

Dynamic stability means that after being displaced from original equilibrium condition, the aeroplane will return to that condition without oscillation

Static stability means that the aeroplane is also dynamically stable about the relevant axis

Dynamic stability is possible only when the aeroplane is statically stable about the relevant axis

A dynamically stable aeroplane would be almost impossible to fly manually

Q50. If an aircraft has positive static stability:

it is always dynamically stable

it is always dynamically unstable

it can be dynamically neutraZIl/stable or unstable

it is always dynamically neutral

Q51. For an aeroplane to possess dynamic stability, it needs:

Static stability and sufficient damping

Static stability only

Sufficient damping only

A large CG range

Q52. Dynamic longitudinal stability requires:

an effective elevator

a small CG range

positive static longitudinal stability

a variable incidence (trimming) tailplane

Q53. The aeroplane motion, schematically illustrated in the annex, is an example of a dynamically:

unstable periodic motion

indifferent periodic motion

stable periodic motion

indifferent periodic motion

Q54. During a phugoid the speed:

varies significantly, as during a short period oscillation

remains approximately constant, as during a short period oscillation

varies significantly, whereas during a short period oscillation it does not

remains approximately constant, whereas during a short period oscillation it varies significantly

Q55. Which statement is correct:

During a phugoid altitude varies significantly, but during a short period oscillation it remains approximately constant

During both a phugoid and a short period oscillation altitude remains approximately constant

During both a phugoid and a short period oscillation altitude varies significantly

During a phugoid altitude remains approximately constant, but during a short period oscillation it varies significantly

Q56. Long period (phugoioscillations are characterised by:

oscillations will take 5 seconds to damp out

speed is constant

long period of damping

rapid and repeated changes in effective angle of attack

Q57. If the airspeed increases and decreases during longitudinal phugoid oscillations, the aircraft:

is constantly changing AOA making it difficult to reduce the magnitude of the oscillations

can be easily controlled by the pilot

will display poor trimming qualities

is displaying lateral dynamic instability

Q58. Longitudinal dynamic oscillation takes two forms. One of these, long period oscillation, involves slow changes in:

height and load factor

height and speed

pitch and load factor

speed and load factor

Q59. Which one of the following statements about the dynamic stability of a conventional aeroplane about the lateral axis is correct?

An aft C.G. position shortens the period time of the phugoid

Speed remains constant during one period of the phugoid

Period time of the phugoid is normally 5 sec

Damping of the phugoid is normally very weak

Q60. During a short period oscillation: the altitude:

Remains approximately constant, whereas during a phugoid it varies significantly

Remains approximately constant, as does during a phugoid

Varies significantly, as it does during a phugoid

Varies significantly, whereas during a phugoid it remains approximately constant

Q61. Short period oscillation is:

pilot induced and unstable

oscillation in pitch

oscillation in roll

oscillation in yaw

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Results

Q1. Which aeroplane behaviour will be corrected by a yaw damper?

Q2. What is the recommended action following failure of the yaw damper(s) of a jet aeroplane, flying at normal cruise altitude and speed prior to encountering Dutch roll problems?

Q3. Which moments or motions interact in a dutch roll?

Q4. When considering the relationship between lateral static stability and directional stability:

Q12. Which of the following gives an unstable contribution in sideslip?

Q13. An example of a combined lateral and directional aperiodic motion is a:

Q14. Sensitivity for spiral dive will occur when:

Q15. Which of the following statements about static lateral and directional stability is correct?

Q16. Sensitivity for spiral dive will occur when:

Q17. When pulling out of a dive the angle of attack:

Q18. The effect of a ventral fin on the static stability of an aeroplane is as follows: (1=longitudinal, 2=lateral, 3=directional)

Q19. Increasing the size of the fin:

Q20. An aeroplane has static directional stability; in a sideslip to the right, initially the:

Q21. An aeroplane has static directional stability if, when in a sideslip with the relative airflow coming from the left, initially the:

Q22. The primary function of the fin is to give:

Q23. The effect of a positive wing sweep on static directional stability is as follows:

Q24. The contribution of wing sweep back to static directional stability is:

Q25. The effect of a wing with sweepback on static directional stability is as follows:

Q26. The contribution of swept back wings to static directional stability:

Q27. The effect of a wing with sweepback on static directional stability is as follows:

Q28. Which of the following provides a positive contribution to static directional stability?

Q29. The contribution of swept back wings to static directional stability :

Q30. The purpose of the dorsal fin is to:

Q31. Static directional stability is mainly provided by:

Q32. An example of a combined lateral and directional periodic motion is a:

Q33. If the static lateral stability of an aeroplane is increased, whilst its static directional stability remains constant:

Q34. An aeroplane is sensitive to Dutch Roll when:

Q35. The tendency to Dutch Roll increases when:

Q36. Which one of the following systems suppresses the tendency to Dutch roll?

Q37. What will increase the sensitivity to Dutch Roll?

Q38. Which of the following increases the tendency for Dutch roll?

Q39. The tendency for Dutch roll increases with:

Q40. What will increase the tendency to Dutch roll?

Q41. Dutch roll is a combination of:

Q42. One of the requirements for positive dynamic stability is:

Q43. The short period mode/oscillation is an:

Q44. One of the requirements for dynamic stability is:

Q45. A statically unstable aeroplane is:

Q46. An aeroplane that has positive static stability:

Q47. The short-period mode of longitudinal dynamic stability is:

Q48. Which statement is correct?

Q49. Which of the following statements is correct?

Q50. If an aircraft has positive static stability:

Q51. For an aeroplane to possess dynamic stability, it needs:

Q52. Dynamic longitudinal stability requires:

Q53. The aeroplane motion, schematically illustrated in the annex, is an example of a dynamically:

Q54. During a phugoid the speed:

Q55. Which statement is correct:

Q56. Long period (phugoioscillations are characterised by:

Q57. If the airspeed increases and decreases during longitudinal phugoid oscillations, the aircraft:

Q58. Longitudinal dynamic oscillation takes two forms. One of these, long period oscillation, involves slow changes in:

Q59. Which one of the following statements about the dynamic stability of a conventional aeroplane about the lateral axis is correct?

Q60. During a short period oscillation: the altitude:

Q61. Short period oscillation is:

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