3767. Reducing the thickness/chord ratio on a wing will: A – reduce the transonic variations in drag coefficient B – reduce the transonic variations in lift coefficient C – delay the onset of shockwave formation
D – all of the above Ref: AIR: atpl; Ans: D
3768. The Mach cone semi-angle:
A – decreases with increasing speed B – increases with increasing speed
C – decreases up to a certain speed, then increases D – remains constant at all speeds above MCRIT Ref: AIR: atpl;
Ans: A
3774. Which of the following flight phenomena can happen at Mach Numbers below the critical Mach number?
A – Dutch roll B – Tuck under C – Mach buffet D – Shock stall Ref: AIR: atpl; Ans: A
3777. The formula for the Mach Number is: (a = speed of sound) is? A – M = TAS*a
B – M = a/TAS C – M = TAS/a D – M = IAS/a
3778. The speed of sound is affected by the: A – pressure of the air
B – density of the air C – temperature of the air D – humidity of the air Ref: AIR: atpl;
Ans: C
3788. If the altitude is increased and the TAS remains constant in the standard troposphere the Mach Number will:
A – not change B – decrease C – increase
D – increase or decrease, depends on the type of aeroplane Ref: AIR: atpl;
Ans: C
3790. An aeroplane is descending at a constant Mach number from FL 350. What is the effect on true airspeed?
A – It remains constant
B – It decreases as pressure increases C – It decreases as altitude decreases D – It increases as temperature increases Ref: AIR: atpl;
Ans: D
3798. The two areas of speed instability in transonic aircraft are: A – above VDmin, above M 0.4
B – below VDmin, M 0.89 to 0.98 C – above VDmin, M 0.75 to 0.81 D – below VDmin, above M 1.0 Ref: AIR: atpl;
3809. As an aircraft accelerates through the transonic speed range: A – The coefficient of drag increases then decreases B – The coefficient of drag increases
C – The coefficient of drag decreases then increases D – The coefficient of drag decreases
Ref: AIR: atpl; Ans: A
3810. The Mach number:
A – increases at a given TAS when the temperature rises
B – is the ratio between the TAS of the aeroplane and the speed of sound at sea level
C – is the ratio between the IAS of the aeroplane and the local speed of sound D – is the ratio between the TAS of the aeroplane and the local speed of sound Ref: AIR: atpl;
Ans: D
3812. Compared to a noarmal transonic airfoil section a supercritical section has: A – a more cambered top surface
B – a flatter to surface C – a flatter bottom surface D – a very sharp leading edge Ref: AIR: atpl;
Ans: B 3813. Shock stall is:
A – separation of the flow behind the bow wave
B – separation of the boundary layer behind the shock wave
C – separation of the flow at high angles of attack and at high Mach Numbers D – separation of the flow at the trailing edge of the wing at high Mach Numbers
3814. In the transonic range the aeroplane characteristics are strongly determined by: A – the CAS
B – the TAS C – the IAS
D – the Mach Number Ref: AIR: atpl;
Ans: D
3816. Should a transport aeroplane fly at a higher Mach number than the buffet-onset Mach number?
A – Yes, but only during approach B – Yes, this causes no problems C – No, this is not acceptable
D – Yes, if you want to fly fast at very high altitudes Ref: AIR: atpl;
Ans: C
3817. A shock stall occurs when laminar flow breaks down: A – behind the shock wave
B – behind the trailing edge C – behind the leading edge
D – at a high angle of attack and high Mach number Ref: AIR: atpl;
Ans: A
3818. Climbing at a constant Mach Number up to FL 350 the TAS will: A – decrease
B – first increase, then decrease C – increase
D – remain constant Ref: AIR: atpl; Ans: A
3821. In the transonic range CLmax will ___ and the 1g stalling speed will ___ A – decrease, increase
B – decrease, decrease C – increase, decrease D – increase, increase Ref: AIR: atpl; Ans: A
3824. The Mach trim system will:
A – pump the fuel from tank to tank, depending on the Mach Number B – keep the Mach Number automatically constant
C – adjust the stabilizer, depending on the Mach Number
D – adjust the elevator trim tab, depending on the Mach Number Ref: AIR: atpl;
Ans: C
3826. The flight Mach number is 0.8 and the TAS is 400 kts. The speed of sound is: A – 480 kts
B – 320 kts C – 500 kts D – 600 kts Ref: AIR: atpl; Ans: C
3829. On a typical symmetrical airfoil, as the free stream Mach number approaches M 1.0, the centre of pressure will:
A – move from 25% chord to the leading edge B – move forward to about 25% chord
C – move aft to about 45% chord D – move aft to the trailing edge
3836. On a typical transonic airfoil the transonic rearward shift of the CP occurs at about: A – M 0.75 to M 0.98 B – M 0.81 to M 1.4 C – M 0.75 to M 0.89 D – M 0.89 to M 0.98 Ref: AIR: atpl; Ans: A
3839. To be able to predict compressibility effects you have to determine the: A – IAS
B – EAS C – TAS
D – Mach Number Ref: AIR: atpl; Ans: D
3846. A jet aeroplane is cruising at high altitude with a Mach-number, that provides a buffet margin of 0.3g incremental. In order to increase the buffet margin to 0.4g incremental the pilot must:
A – fly at a lower altitude and the same Mach-number B – extend the flaps to the first selection
C – fly at a higher Mach-number D – fly at a larger angle of attack Ref: AIR: atpl;
Ans: A
3861. Which statement with respect to the speed of sound is correct? A – Varies with the square root of the absolute temperature B – Increases always if the density of the air decreases C – Is independent of altitude
D – Doubles if the temperature increases from 9o to 36o Centigrade
Ref: AIR: atpl; Ans: A
21034. Assuming ISA conditions, climbing at a constant Mach Number up the tropopause the TAS will:
A – first increase, then decrease B – decrease
C – increase
D – remain constant Ref: AIR: atpl; Ans: B
21043. During a climb at a constant IAS, the Mach number will: A – remain constant
B – decrease initially and increase subsequently C – increase
D – increase initially and remain constant subsequently Ref: AIR: atpl;
Ans: C
21124. The Mach number is the ratio between the:
A – TAS of the aeroplane and the speed of sound at sea level
B – TAS of the aeroplane and speed of sound of the undisturbed flow C – IAS of the aeroplane and the speed of sound of the undisturbed flow D – IAS of the aeroplane and the speed of sound at sea level
Ref: AIR: atpl; Ans: B
21136. Transonic speed is:
A – a speed at which locally around the aeroplane both supersonic and subsonic speeds exist
B – a speed at which locally an oblique shock wave has developed in the flow along the aeroplane
C – a speed at which compressibility effects are first noticeable D – the speed range between Mcrit and MMO
23274. An aircraft flying at 0.5M would be flying at: A – half the speed of sound at ground level only B – half the speed of sound at the tropopause only
C – half the speed of sound under all conditions in the atmosphere D – half the speed of sound at sea level only
Ref: AIR: atpl; Ans: C
23503. The Mach number corresponding to a given TAS will: A – be greater if temperature increases
B – be less if temperature increases C – be the same at all temperatures
D – temperature does not affect the mach number because it is a ratio Ref: AIR: atpl;
Ans: B
23504. For a constant flight level and IAS, if the OAT increases, the Mach number will:
A – increase B – decrease
C – remain constant Ref: AIR: atpl; Ans: C
23552. The mach number will remain constant if the OAT increases whilst an aircraft is flying at a constant flight level and CAS because:
A – when flying at a constant flight level the aircraft will change height as the actual pressure of the atmosphere changes, thus maintaining the same TAS and speed of sound
B – the speed of sound and the TAS both increase with the square root of the absolute temperature of the air
C – the aircraft is flying above the tropopause, where the air temperature remains constant, and the TAS will remain the same if the CAS remains constant
D – the mach meter has become unserviceable, if the air temperature increases the speed of sound will increase
Ref: AIR: atpl; Ans: B
23553. Vmo can be exceeded in a descent at a constant mach number because:
A – Vmo is an IAS and descending at a constant mach will require a decrease in TAS which will reduce dynamic pressure
B – as altitude is reduced the speed of sound will increase which increases IAs C – as altitude decreases the ASI will start to under-read due to the increasing air density
D – Vmo is an IAS and descending at a constant mach will require an increase in TAS which will increase dynamic pressure
Ref: AIR: atpl; Ans: D
23604. An aircraft is descending at a constant mach number, which of the following operational speed limitations may be exceeded?
A – Vmo B – Vne C – Mmo D – Vd
Ref: AIR: atpl; Ans: A
23619. The speed of sound is affected by the: A – density
B – humidity C – pressure D – temperature Ref: AIR: atpl; Ans: D
23680. What happens to mach number if IAS is increased when flying at FL390? A – remain constant
B – increase C – decrease
23704. The local speed of sound: A – is independent of altitude
B – will double if temperature varies from 9o to 36o
C – is dependent on the square root of the absolute temperature D – decreases with increasing density
Ref: AIR: atpl; Ans: C
24459. In a steady climb:
A – At a steady IAS, Mach number remains constant because Mach number is only proportional to TAS and inversely proportional to the local speed of sound
B – At steady IAS, Mach number will increase
C – At a steady IAS, Mach number will remain constant because the local speed of sound is proportional to the square root of the absolute temperature
D – At a steady IAS, Mach number will decrease because the absolute temperature will decrease
Ref: AIR: atpl; Ans: B