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Matthias Nott
5 days ago e07a553414967d3a090c9b2feea2d1fdfab082a7 
 SPL Exam Questions EN/80 - Principles of Flight.md
....@@ -68,6 +68,8 @@
6868 
6969 [DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q4) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q4)
7070 
71
+![](figures/Anatomy_sailplane_EN.png)
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+
7173 - A) Ailerons
7274 - B) Wing flaps
7375 - C) Vertical rudder
....@@ -583,7 +585,15 @@
583585 
584586 #### Explanation
585587 
586
-In the pre-stall regime, the lift coefficient CL increases approximately linearly with angle of attack (AoA). The slope of this line is the lift curve slope (typically about 2π per radian for a thin aerofoil). This linear relationship continues until the critical angle of attack is reached, at which point flow separation causes CL to peak (CL_max) and then drop sharply — the stall. The linearity of the CL vs. AoA relationship is one of the foundational results of aerodynamic theory.
588
+The lift formula is:
589
+
590
+**L = CL x ½ρv² x S**
591
+
592
+where CL is the lift coefficient, ρ is air density, v is airspeed, and S is wing area. In the pre-stall regime, CL increases approximately linearly with angle of attack (AoA):
593
+
594
+**CL ≈ CL₀ + a x α**
595
+
596
+where a is the lift curve slope (typically about 2π per radian ≈ 0.11 per degree for a thin aerofoil), CL₀ is CL at zero AoA, and α is the angle of attack. This linear relationship continues until the critical angle of attack is reached, at which point flow separation causes CL to peak (CL_max) and then drop sharply — the stall.
587597 
588598 #### Key Terms
589599 
....@@ -847,7 +857,15 @@
847857 
848858 #### Explanation
849859 
850
-This is the definitive stall characteristic: lift collapses because boundary layer separation destroys the pressure differential that generates it, while drag rises dramatically due to the large turbulent separated wake. The CL vs. AoA curve shows CL_max at the critical angle, then a steep drop — this is the stall. The CD vs. AoA curve rises steeply through and beyond the stall. This combination (less lift, more drag) is why the stall is critical — the aircraft loses lift while simultaneously experiencing high drag that would further reduce speed.
860
+This is the definitive stall characteristic: lift collapses because boundary layer separation destroys the pressure differential that generates it, while drag rises dramatically due to the large turbulent separated wake.
861
+
862
+The lift and drag formulas show why:
863
+
864
+**L = CL x ½ρv² x S** (Lift = Lift Coefficient x dynamic pressure x wing area)
865
+
866
+**D = CD x ½ρv² x S** (Drag = Drag Coefficient x dynamic pressure x wing area)
867
+
868
+At the stall, CL drops sharply (past CL_max on the CL vs. AoA curve), so lift falls. At the same time, CD rises steeply due to the massive flow separation, so drag increases. This combination (less lift, more drag) is why the stall is critical — the aircraft loses lift while simultaneously experiencing high drag that further reduces speed.
851869 
852870 #### Key Terms
853871 
....@@ -934,6 +952,8 @@
934952 
935953 [DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q47) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q47)
936954 
955
+![](figures/Boundary_layer_EN.svg)
956
+
937957 - A) The transition point and the separation point
938958 - B) The stagnation point and the centre of pressure
939959 - C) The transition point and the centre of pressure
....@@ -950,6 +970,8 @@
950970 ### Q48: What types of boundary layers are found on an aerofoil? ^t80q48
951971 
952972 [DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q48) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q48)
973
+
974
+![](figures/Boundary_layer_EN.svg)
953975 
954976 - **A)** Turbulent layer at the leading edge areas, laminar boundary layer at the trailing areas
955977 - **B)** Laminar boundary layer along the complete upper surface with non-separated airflow
....@@ -984,6 +1006,8 @@
9841006 ### Q50: Which structural element provides lateral (roll) stability? ^t80q50
9851007 
9861008 [DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q50) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q50)
1009
+
1010
+![](figures/Anatomy_sailplane_EN.png)
9871011 
9881012 - **A)** Elevator
9891013 - **B)** Wing dihedral
....@@ -1296,10 +1320,10 @@
12961320 
12971321 > ![](figures/t80_q66.png)
12981322 
1299
-> *A = tangent from the origin → best glide speed (best L/D ratio, best glide)*
1300
-> *B = tangent from a point shifted to the right on the V axis → best glide with headwind*
1301
-> *C = tangent from a point above the origin on the W axis (McCready) → optimal inter-thermal speed; touches the polar at the point of minimum sink rate*
1302
-> *D = horizontal line at the level of minimum sink rate → indicates the minimum sink speed (Vmin sink)*
1323
+> *A = tangent from a point above the origin on the W axis (McCready) → optimal inter-thermal cruise speed*
1324
+> *B = tangent from the origin → best glide speed (best L/D ratio)*
1325
+> *C = tangent from a point shifted to the right on the V axis → best glide with headwind*
1326
+> *D = horizontal tangent at the top of the polar → minimum sink rate speed (Vmin sink)*
13031327 
13041328 - A) Tangent (A)
13051329 - B) Tangent (B)
....@@ -1308,11 +1332,13 @@
13081332 
13091333 #### Answer
13101334 
1311
-D)
1335
+C)
13121336 
13131337 #### Explanation
13141338 
1315
-On the speed polar (curve showing the sink rate W as a function of horizontal speed V), the point of minimum sink rate corresponds to the lowest point of the curve (the smallest value of W in absolute terms). The tangent at this point is a horizontal tangent — this is tangent ****(C)**** on the diagram. This point corresponds to the minimum sink speed, used to maximise flight time or to exploit thermals. The tangent drawn from the origin to the polar (tangent B) gives the speed for the best L/D ratio (best glide ratio).
1339
+On the speed polar (sink rate W vs. airspeed V), the minimum sink rate is at the highest point of the curve (least negative W). At that point the tangent to the curve is horizontal — this is tangent **(D)** on the diagram. Flying at this speed maximises flight time and is used when circling in thermals.
1340
+
1341
+The other tangents: **(B)** from the origin gives best L/D (best glide angle). **(C)** from a right-shifted point on V compensates for headwind. **(A)** from a point above the origin on the W axis is the McCready tangent for optimal inter-thermal cruise speed.
13161342 
13171343 ### Q67: Induced drag increases ^t80q67
13181344 
....@@ -1459,22 +1485,32 @@
14591485 
14601486 [DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q74) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q74)
14611487 
1462
-- **A)** 15 degrees C and 1013.25 hPa
1463
-- **B)** 59 degrees C and 29.92 hPa
1464
-- **C)** 15 degrees C and 1013.25 Hg
1465
-- **D)** 15 degrees F and 29.92 Hg
1488
+- **A)** 15 °C and 1013.25 hPa
1489
+- **B)** 59 °C and 29.92 hPa
1490
+- **C)** 15 °C and 1013.25 inHg
1491
+- **D)** 15 °F and 29.92 inHg
14661492 
14671493 #### Answer
14681494 
1469
-D)
1495
+A)
14701496 
14711497 #### Explanation
14721498 
1473
-The pressure in ICAO standard atmosphere at sea level is 1013.25 hPa (millibars) = 29.92 inches of mercury (inHg). 29.92 hPa is incorrect.
1499
+The ICAO Standard Atmosphere sea-level values are:
1500
+- **Temperature**: 15 °C (= 288.15 K = 59 °F)
1501
+- **Pressure**: 1013.25 hPa (= 1013.25 mbar = 29.92 inHg = 760 mmHg)
1502
+
1503
+Option **A** matches both.
1504
+
1505
+- **B** is wrong on both counts: 59 is in °F, not °C; and 29.92 is in inHg, not hPa.
1506
+- **C** has the right temperature but the wrong unit for the pressure value: 1013.25 is in hPa, not inHg.
1507
+- **D** has the wrong temperature (15 °F is far below the standard 15 °C), although the pressure number (29.92 inHg) is correct.
14741508 
14751509 #### Key Terms
14761510 
1477
-ICAO = International Civil Aviation Organization
1511
+- **ICAO** = International Civil Aviation Organization
1512
+- **hPa** = hectopascal (= mbar)
1513
+- **inHg** = inches of mercury
14781514 ### Q75: Regarding airflow, the simplified continuity equation states: At the same moment, the same mass of air passes through different cross-sections. Therefore: ^t80q75
14791515 
14801516 [DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q75) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q75)
....@@ -3435,3 +3471,316 @@
34353471 In ground effect (within approximately one wingspan of the surface), the ground physically constrains wingtip vortex development, reducing downwash. This increases the effective angle of attack (raising lift) while simultaneously reducing induced drag. Pilots notice this as a floating sensation during the landing flare.
34363472 
34373473 - **Options A, B, and C** all incorrectly describe the lift-drag relationship — the correct combination is increased lift with decreased induced drag.
3474
+
3475
+### Q163: Does air density affect the minimum speed (IAS) of a glider? ^t80q163
3476
+
3477
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q163) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q163)
3478
+
3479
+- **A)** Yes, it increases when air density decreases
3480
+- **B)** Yes, it decreases when density decreases
3481
+- **C)** No, the minimum speed in IAS does not depend on air density
3482
+- **D)** Yes, it increases when density increases
3483
+
3484
+#### Answer
3485
+
3486
+C)
3487
+
3488
+#### Explanation
3489
+
3490
+Stall occurs when the wing reaches its critical angle of attack. The stall speed in IAS is Vs = sqrt(2W / (rho0 x S x CL_max)), where rho0 is the reference density used by the airspeed indicator. The ASI measures dynamic pressure (q = 0.5 x rho x TAS^2) and displays it as IAS. Since lift L = CL x q x S, the stall always occurs at the same CL_max regardless of density. Therefore the indicated stall speed (IAS) remains constant at any altitude or density - this is why all reference speeds in procedures are given as IAS.
3491
+
3492
+#### Key terms
3493
+
3494
+- **IAS** = Indicated Airspeed
3495
+- **TAS** = True Airspeed
3496
+- **CL_max** = Maximum lift coefficient before stall
3497
+
3498
+### Q164: In which speed range can vibrations and flutter occur? ^t80q164
3499
+
3500
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q164) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q164)
3501
+
3502
+- **A)** From Vs to Va
3503
+- **B)** From Va to Vne
3504
+- **C)** Above Vne
3505
+- **D)** From Vs to Vne
3506
+
3507
+#### Answer
3508
+
3509
+C)
3510
+
3511
+#### Explanation
3512
+
3513
+Aeroelastic flutter is a self-sustaining, divergent oscillation of control surfaces or lifting surfaces. Its onset speed is deliberately set above Vne. In normal flight below Vne, properly mass-balanced controls and a sufficiently rigid structure prevent flutter. By exceeding Vne, the aircraft enters a regime where flutter becomes a real risk and can lead to structural destruction within seconds.
3514
+
3515
+#### Key terms
3516
+
3517
+- **Vne** = Never Exceed Speed
3518
+- **Va** = Manoeuvring Speed
3519
+- **Vs** = Stall Speed
3520
+
3521
+### Q165: Vibrations can occur when ^t80q165
3522
+
3523
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q165) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q165)
3524
+
3525
+- **A)** Controls and flaps have excessive play
3526
+- **B)** The load factor is too low in flight
3527
+- **C)** The manoeuvring speed Va is below normal
3528
+- **D)** None of the answers is correct
3529
+
3530
+#### Answer
3531
+
3532
+A)
3533
+
3534
+#### Explanation
3535
+
3536
+Excessive play in the mechanical linkages of control surfaces or flaps creates conditions favourable to vibration by reducing structural damping. The play allows surfaces to move freely under aerodynamic forces, potentially generating oscillations. This is one reason why control system play is strictly limited and checked during maintenance inspections. Large amounts of play can lower the flutter onset speed to below Vne.
3537
+
3538
+### Q166: Vibrations can also occur under which conditions? ^t80q166
3539
+
3540
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q166) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q166)
3541
+
3542
+- **A)** With excessive negative acceleration
3543
+- **B)** When severe turbulence is present at speed Va
3544
+- **C)** With ice on control surfaces and airbrakes, or at high speed
3545
+- **D)** None of the answers is correct
3546
+
3547
+#### Answer
3548
+
3549
+C)
3550
+
3551
+#### Explanation
3552
+
3553
+Ice on control surfaces alters their mass distribution and thus their mass balance. Mass balancing is designed to position the control surface's centre of mass at or ahead of the hinge axis, preventing flutter. Ice, depositing mainly on leading edges and outer surfaces, can shift the centre of mass behind the hinge and lower the critical flutter speed well below Vne. Flying at high speed with ice-contaminated, unbalanced control surfaces is particularly dangerous.
3554
+
3555
+### Q167: In which speed range can the maximum load factor be exceeded, leading to structural overload? ^t80q167
3556
+
3557
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q167) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q167)
3558
+
3559
+- **A)** From Vs to Vne
3560
+- **B)** From Va to Vne
3561
+- **C)** From Vs to Va
3562
+- **D)** Below manoeuvring speed Va
3563
+
3564
+#### Answer
3565
+
3566
+B)
3567
+
3568
+#### Explanation
3569
+
3570
+Below Va, full control deflection causes the wing to stall before the structural limit load is reached - the stall protects the structure. Above Va, the wing can generate enough lift to exceed the limit load factor before stalling. It is in the Va-Vne range that abrupt manoeuvres or severe gusts can subject the structure to excessive loads. Above Vne, the flutter risk is added to the overload risk.
3571
+
3572
+#### Key terms
3573
+
3574
+- **Va** = Manoeuvring speed - speed below which full deflections are safe
3575
+- **Vne** = Never exceed speed
3576
+
3577
+### Q168: Above which speed can abrupt or full control deflections damage the glider's structure? ^t80q168
3578
+
3579
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q168) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q168)
3580
+
3581
+- **A)** Manoeuvring speed Va
3582
+- **B)** Minimum speed Vs
3583
+- **C)** Never exceed speed Vne
3584
+- **D)** Normal cruise speed
3585
+
3586
+#### Answer
3587
+
3588
+A)
3589
+
3590
+#### Explanation
3591
+
3592
+Manoeuvring speed Va is precisely the speed above which abrupt or full control deflections can produce aerodynamic loads exceeding the aircraft's structural limits. Below Va, the wing stalls before these loads are reached. Above Va, a full deflection can generate enough lift or control surface force to damage spars, wing attachments or the tailplane. Va is therefore the practical limit for energetic manoeuvres and turbulence penetration.
3593
+
3594
+### Q169: When the maximum load factor is exceeded, what is the primary risk? ^t80q169
3595
+
3596
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q169) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q169)
3597
+
3598
+- **A)** That the glider stalls
3599
+- **B)** That the glider enters a spin
3600
+- **C)** That stability deteriorates
3601
+- **D)** That the glider's structure is damaged
3602
+
3603
+#### Answer
3604
+
3605
+D)
3606
+
3607
+#### Explanation
3608
+
3609
+The maximum (limit) load factor is the highest load the glider's structure can withstand repeatedly without permanent deformation. Beyond the ultimate factor (typically 1.5 times the limit), structural failure can occur. Exceeding the limit load factor during abrupt manoeuvres or in turbulence can cause deformation or rupture of wing spars, fuselage attachments or control surfaces. Stall and spin are aerodynamic phenomena, not structural ones, and occur at insufficient load factors, not excessive ones.
3610
+
3611
+### Q170: The mass balance (mass balancing) of an aileron has lost lead weights. What can be the consequence? ^t80q170
3612
+
3613
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q170) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q170)
3614
+
3615
+- **A)** Greater adverse yaw
3616
+- **B)** Aileron flutter (vibration)
3617
+- **C)** Reduced aileron forces
3618
+- **D)** The glider becomes unstable about the pitch axis
3619
+
3620
+#### Answer
3621
+
3622
+B)
3623
+
3624
+#### Explanation
3625
+
3626
+Mass balancing places lead counterweights ahead of the hinge axis to bring the control surface's centre of mass to or ahead of that axis. If these counterweights fall off, the centre of mass shifts aft of the hinge. The control surface then becomes susceptible to flutter - a self-amplifying aeroelastic oscillation in which inertial and aerodynamic forces reinforce each other. This flutter can quickly become divergent and destroy the control surface and airframe. That is why any damage to control surface counterweights requires inspection before the next flight.
3627
+
3628
+### Q171: What is the danger of flying at minimum speed in turbulent air? ^t80q171
3629
+
3630
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q171) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q171)
3631
+
3632
+- **A)** Structural overload
3633
+- **B)** Centre of gravity shift
3634
+- **C)** Flow separation (stall)
3635
+- **D)** Elevator flutter
3636
+
3637
+#### Answer
3638
+
3639
+C)
3640
+
3641
+#### Explanation
3642
+
3643
+At minimum speed (stall speed), the wing operates at its maximum lift coefficient CL_max with virtually no margin before stall. In turbulent air, upward gusts can suddenly increase the angle of attack beyond the critical angle, causing an instantaneous stall. In addition, speed fluctuations induced by turbulence can momentarily reduce airspeed below Vs. This is why it is particularly dangerous to fly at minimum speed in rough air, especially on final approach during landing.
3644
+
3645
+### Q172: How does air density change when temperature increases? ^t80q172
3646
+
3647
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q172) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q172)
3648
+
3649
+- **A)** It decreases
3650
+- **B)** It increases
3651
+- **C)** It does not change
3652
+- **D)** It first increases then decreases
3653
+
3654
+#### Answer
3655
+
3656
+A)
3657
+
3658
+#### Explanation
3659
+
3660
+According to the ideal gas law (P = rho x R x T), at constant pressure, an increase in temperature T causes a decrease in density rho. Warmer air is less dense. For a glider, this means performance degrades in hot conditions (density altitude higher than actual altitude): lift and drag are reduced for a given indicated airspeed, and the true airspeed (TAS) at stall is higher. This is the density altitude effect on aircraft performance.
3661
+
3662
+#### Key terms
3663
+
3664
+- **rho** = air density (kg/m3)
3665
+- **R** = gas constant
3666
+- **T** = absolute temperature (Kelvin)
3667
+
3668
+### Q173: In what proportion does drag change with airspeed? ^t80q173
3669
+
3670
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q173) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q173)
3671
+
3672
+- **A)** Linearly (proportional to speed)
3673
+- **B)** As the cube of speed
3674
+- **C)** As the square of speed (quadratically)
3675
+- **D)** Independently of speed
3676
+
3677
+#### Answer
3678
+
3679
+C)
3680
+
3681
+#### Explanation
3682
+
3683
+Parasite drag is proportional to dynamic pressure q = 0.5 x rho x V^2. If speed doubles, q quadruples and therefore parasite drag quadruples as well. This quadratic (square) relationship means a small speed increase produces a large drag increase. This is why gliders flying at high speed lose much more altitude per unit of distance - drag grows far faster than any additional lift available.
3684
+
3685
+#### Key terms
3686
+
3687
+- **q** = dynamic pressure (q = 0.5 x rho x V^2)
3688
+- **V** = airspeed
3689
+
3690
+### Q174: What is understood by static pressure? ^t80q174
3691
+
3692
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q174) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q174)
3693
+
3694
+- **A)** The pressure inside the cockpit
3695
+- **B)** The pressure measured by the pressure tube (Pitot)
3696
+- **C)** The ambient (atmospheric) air pressure
3697
+- **D)** The pressure of the moving airflow
3698
+
3699
+#### Answer
3700
+
3701
+C)
3702
+
3703
+#### Explanation
3704
+
3705
+Static pressure is the pressure exerted by the surrounding atmosphere on an object at rest relative to the air. It is measured by static ports (flush orifices on the fuselage, away from airflow disturbance). It decreases with altitude according to the standard atmosphere model. In the Pitot-static system, static pressure is subtracted from total pressure (Pitot) to obtain dynamic pressure, which is proportional to the square of true airspeed - this is the operating principle of the airspeed indicator.
3706
+
3707
+### Q175: How does the maximum permissible speed Vne of a glider in IAS behave as altitude increases? ^t80q175
3708
+
3709
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q175) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q175)
3710
+
3711
+- **A)** It stays the same
3712
+- **B)** It increases
3713
+- **C)** It decreases
3714
+- **D)** It stays the same because the airspeed indicator is compensated
3715
+
3716
+#### Answer
3717
+
3718
+C)
3719
+
3720
+#### Explanation
3721
+
3722
+Vne is a structural limit tied to true airspeed (TAS), since aerodynamic forces and flutter risk depend on TAS. The airspeed indicator measures IAS (based on dynamic pressure). At altitude, density decreases, so the same IAS corresponds to a higher TAS. To keep the TAS limit constant, the IAS limit must be reduced. Thus the Vne in IAS as shown on the airspeed indicator decreases with altitude. Some AFMs give Vne as TAS (constant) and specify the IAS reduction per altitude band.
3723
+
3724
+#### Key terms
3725
+
3726
+- **Vne** = Never Exceed Speed
3727
+- **IAS** = Indicated Airspeed
3728
+- **TAS** = True Airspeed
3729
+- **AFM** = Aircraft Flight Manual
3730
+
3731
+### Q176: In what proportion does lift change when airspeed increases? ^t80q176
3732
+
3733
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q176) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q176)
3734
+
3735
+- **A)** Linearly
3736
+- **B)** Quadratically (as the square of speed)
3737
+- **C)** As the cube of speed
3738
+- **D)** Independently of speed
3739
+
3740
+#### Answer
3741
+
3742
+B)
3743
+
3744
+#### Explanation
3745
+
3746
+Lift L = CL x 0.5 x rho x V^2 x S. At constant angle of attack and density, lift is proportional to V^2. If speed doubles, lift quadruples. This property allows flight at high speed with a lower angle of attack - the lift generated scales with the square of speed. It also explains why stall speeds increase with the square root of the load factor: in a turn, more lift is required, demanding a higher speed to avoid stalling.
3747
+
3748
+### Q177: Which statement is FALSE regarding the relationship between lift/drag and airspeed? ^t80q177
3749
+
3750
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q177) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q177)
3751
+
3752
+- **A)** Lift increases when speed increases
3753
+- **B)** Drag changes as a function of speed
3754
+- **C)** Lift and drag vary linearly as a function of speed
3755
+- **D)** Lift varies as a function of changes in angle of attack
3756
+
3757
+#### Answer
3758
+
3759
+C)
3760
+
3761
+#### Explanation
3762
+
3763
+The FALSE statement is C. Neither lift nor drag varies linearly with speed - both vary as the square of speed (proportionally to dynamic pressure q = 0.5 x rho x V^2). Doubling speed quadruples both lift AND drag (at constant angle of attack). Statements A, B and D are correct: lift does increase with speed, drag does vary with speed, and lift does depend on angle of attack via the lift coefficient CL.
3764
+
3765
+### Q178: What is understood by total pressure? ^t80q178
3766
+
3767
+[DE](../SPL%20Exam%20Questions%20DE/80%20-%20Grundlagen%20des%20Fliegens.md#^t80q178) · [FR](../SPL%20Exam%20Questions%20FR/80%20-%20Principes%20du%20vol.md#^t80q178)
3768
+
3769
+- **A)** The pressure inside the cockpit
3770
+- **B)** The pressure of air at the Earth's surface
3771
+- **C)** The sum of static pressure and dynamic pressure
3772
+- **D)** The ambient air pressure
3773
+
3774
+#### Answer
3775
+
3776
+C)
3777
+
3778
+#### Explanation
3779
+
3780
+Total pressure (or stagnation pressure) is the pressure measured when the airflow is brought to rest isentropically. It equals the sum of static pressure (ambient atmospheric pressure) and dynamic pressure (0.5 x rho x V^2). The Pitot tube measures total pressure by stagnating the airflow at its inlet. By subtracting static pressure (measured by the static port) from total pressure (measured by the Pitot), one obtains dynamic pressure, which allows calculation of indicated airspeed.
3781
+
3782
+#### Key terms
3783
+
3784
+- **Dynamic pressure** = 0.5 x rho x V^2
3785
+- **Static pressure** = ambient atmospheric pressure
3786
+- **Total pressure** = static pressure + dynamic pressure