OGPERF02: Effect of CG Shift – SET 1

Correct answer is – It would be statically unstable. – Aft of neutral point results in instability

Correct answer is – Increased fuel consumption and reduced range. – Forward C of G increases drag and power required reducing efficiency

Correct answer is – Increased trim drag and stability. – Forward C of G increases stability but requires greater trim force increasing drag

Correct answer is – C of G to move aft slightly. – Nose gear retracting rearwards shifts mass aft slightly

Correct answer is – (v). – All listed effects occur with rearward C of G

Correct answer is – It would be neutrally statically stable. – Neutral point corresponds to zero static stability

Correct answer is – Increased threshold speed and increased risk of undercarriage damage. – Higher mass increases approach speed and landing loads

Correct answer is – Increased stability and trim drag. – Forward C of G increases stability but increases tail force and drag

Correct answer is – Take-off safety speeds VR VMU and VLOF are increased. – Increased mass raises required lift-off speeds

Correct answer is – Rate of climb is decreased because more power is required. – Increased mass increases power required reducing climb

Correct answer is – Increase the stick force required to rotate for take-off. – Forward C of G increases tail downforce required and stick force

Correct answer is – Endurance is decreased because drag is increased. – Increased mass increases drag and fuel consumption reducing endurance

Correct answer is – Decrease the glide endurance. – Forward C of G increases drag reducing endurance

Correct answer is – It would be neutrally statically stable. – Neutral point corresponds to zero static stability

Correct answer is – Decreased take-off performance and climb gradient. – Increased mass reduces performance and climb capability

Correct answer is – TODR is increased. – Increased mass reduces acceleration and increases take-off distance

Correct answer is – Increases stalling speed. – Forward C of G increases required lift and stall speed

Correct answer is – Gear extension will move the C of G aft. – Nose gear forward movement shifts C of G forward

Correct answer is – Increase speed for best glide range. – Forward C of G increases drag shifting optimum glide speed higher

Correct answer is – Increases stability. – Forward C of G increases longitudinal stability

Correct answer is – Engine-out performance is decreased. – Increasing all-up mass increases the lift required which increases induced drag; this reduces excess thrust available especially in engine-out condition, therefore climb performance and engine-out capability are reduced

Correct answer is – Take-off safety speed V₂ is increased. – Increased aircraft mass requires higher lift-off and safety speeds because greater lift must be generated, resulting in higher V₂ while climb gradient and range are adversely affected

Correct answer is – It would be statically unstable. – If C of G moves aft of the neutral point the restoring moment disappears and becomes divergent, causing instability in pitch

Correct answer is – Decreases stalling speed. – Rearward C of G reduces tail downforce, reducing total lift required from wings, hence lower stalling speed and improved aerodynamic efficiency

Correct answer is – It would be very sensitive to pitch control inputs and difficult to trim. – With C of G near aft limit stability is reduced; aircraft becomes highly responsive to pitch inputs and requires continuous trimming, making control more difficult

Correct answer is – (i), (iii), and (vi). – Forward loading shifts C of G forward increasing landing distance, requiring greater stick force for rotation and increasing drag which reduces range; VLOF does not decrease and VMCA is largely unaffected

Correct answer is – Climb gradient is reduced because more power is required. – Increased mass increases drag and reduces excess power leading to poorer climb gradient; range does not increase and landing distance increases

Correct answer is – Decreased take-off and climb gradient. – Higher mass increases drag and required lift, reducing acceleration and climb capability, degrading overall performance

Correct answer is – Obstacle clearance requirements. – In mountainous terrain obstacle clearance after take-off is critical even if runway and conditions are favourable, thus limiting take-off mass

All of the above.

Correct answer is – Decreases stability. – Moving C of G aft reduces the restoring pitching moment, decreasing longitudinal static stability and making the aircraft more sensitive in pitch

Correct answer is – (ii) and (iv) only. – Forward C of G increases VLOF and reduces aerodynamic efficiency leading to reduced range; LDR does not decrease and stick force increases not decreases

Gear retraction will move the C of G forward.

Correct answer is – Increases stalling speed. – Higher mass requires greater lift coefficient increasing stall speed according to lift equation

Correct answer is – It would be statically unstable. – With C of G aft of neutral point, any disturbance produces a diverging pitching moment resulting in instability

Correct answer is – Decreased take-off and climb gradient. – Increased mass increases drag and reduces excess thrust, degrading climb and take-off performance

Correct answer is – (i) and (iv). – Forward C of G increases landing distance, does not significantly affect minimum control speeds, and increases (not decreases) rotation force

Correct answer is – Stabiliser trim setting changes. – C of G depends only on total mass and its distribution; trim changes only alter stabiliser angle of incidence and pitching moment but do not change mass distribution, therefore no shift in C of G

Correct answer is – (iii), (iv) and (vi). – Forward loading increases take-off mass and moves C of G forward causing increased stick force for rotation; minimum control speeds remain unchanged as they depend on thrust/control authority; increased drag and fuel consumption reduce range