Self-test

Test your knowledge of the main 030 topics. Answers at the end.

Questions

1. Define density altitude and explain its effect on climb performance.
2. State the definitions of Vx and Vy and what changes them.
3. Compute the CG given: empty 750 kg × arm 0.95 m + pilot/copilot 160 kg × arm 1.04 m + rear pax 70 kg × arm 1.90 m + baggage 15 kg × arm 2.41 m + fuel 115 kg × arm 1.17 m.
4. State the minimum final reserve for VFR day and VFR night under NCO.OP.125.
5. Wind 250°/20 kt, runway 22 — compute headwind and crosswind components.
6. Why does aft CG reduce stall speed?
7. From PA 4 000 ft and OAT +25 °C, compute density altitude.
8. Name the four corrections to convert TT (true track) into CH (compass heading).
9. Define TODR, TODA, TORA, ASDA, LDA.
10. At what airspeed does a typical piston trainer achieve best range, and why?

Answers

1. DA = pressure altitude corrected for ISA deviation. Higher DA → lower air density → lower engine power + lower lift → lower RoC and shallower climb gradient. Rule of thumb: DA = PA + 120 × ISA dev. See §2.2.
2. Vx = best angle of climb (height/distance) for obstacle clearance. Vy = best rate of climb (height/time) for normal climb to cruise. Vx < Vy in piston aircraft. Both vary slightly with mass and DA. See §2.1.
3. CG = Σ(moments) / Σ(masses) = (712.5 + 166.4 + 133 + 36.2 + 134.6) / (750 + 160 + 70 + 15 + 115) = 1 182.7 / 1 110 = 1.066 m aft of datum. See §1.4.
4. VFR day: 30 min final reserve after landing at destination. VFR night: 45 min. NCO.OP.125. See §3.2.
5. α = 250° − 220° = 30°. Crosswind = 20 × sin(30°) = 10 kt. Headwind = 20 × cos(30°) ≈ 17 kt. See §7.
6. With aft CG the elevator needs less downforce to keep the aircraft in trim → main wing carries less additional load from the tail downforce reaction → lower effective wing load → lower stall speed. See §1.1.
7. ISA temp at PA 4 000 ft = 15 − 2 × 4 = +7 °C. ISA dev = 25 − 7 = +18 °C. DA ≈ 4 000 + 120 × 18 = 6 160 ft. See §2.2.
8. CDMVT sequence (T → C backwards): TT → (− WCA) → TH → (± variation) → MH → (± deviation) → CH. See §3.1.
9. TODR = take-off distance required (AFM); TODA = take-off distance available (TORA + clearway); TORA = take-off run available; ASDA = accelerate-stop distance available; LDA = landing distance available. See §2.4.
10. At the speed for minimum drag (best L/D), typically about 1.32 × Vs1 for piston trainers. At this speed L/D is maximum — most nm per kg fuel. See §2.6.

Note: These questions are a revision aid. Use the ECQB practice questions of your NAA in addition.