Tag Archives: stability

Which statement concerning the tropopause is correct?

A: Above the tropopause no clear air turbulence occurs
B: The layer just above the tropopause is absolutely stable
C: In the ICAO standard atmosphere the tropopause lies lower over the Poles than over the equator
D: The temperature at the tropopause is approximately -80(degrees)C over the Poles and approximately -40(degrees)C over the equator

 

 

 

 

 

 

 

 

Answer: B

Positive static lateral stability is the tendency of an aeroplane to:

A: roll to the right in a right turn.
B: roll to the left in the case of a sideslip angle (with the aeroplane nose pointing to the right of the incoming flow).
C: roll to the left in the case of a sideslip (with the aeroplane nose pointing to the left of the incoming flow).
D: roll to the left in a right turn.

 

 

 

 

 

 

 

 

Answer: C

An aeroplane exhibits static longitudinal stability, if, when the angle of attack changes:

A: the resulting moment is positive.
B: the change in total aeroplane lift acts through the centre of gravity.
C: the change in total aeroplane lift acts aft of the centre of gravity.
D: the change in wing lift is equal to the change in tail lift.

 

 

 

 

 

 

 

 

Answer: C

Static lateral stability should not be too large, because:

A: too much rudder deflection would be required in a crosswind landing.
B: too much aileron deflection would be required in a crosswind landing.
C: constant aileron deflection would be required during cruise in case of crosswind.
D: the roll trim sensitivity would increase sharply.

 

 

 

 

 

 

 

 

Answer: B

Which statement on dynamic longitudinal stability of a conventional aeroplane is correct?

A: Speed remains constant during one period of the phugoid.
B: Damping of the phugoid is normally very weak.
C: Period time of the phugoid is normally 5 s.
D: Damping of the short period oscillation is normally very weak.

 

 

 

 

 

 

 

 

Answer: B

Longitudinal static stability is created by the fact that the:

A: centre of gravity is located in front of the leading edge of the wing.
B: centre of gravity is located in front of the neutral point of the aeroplane.
C: wing surface is greater than the horizontal tail surface.
D: aeroplane possesses a large trim speed range.

 

 

 

 

 

 

 

 

Answer: B