M&B- 2: Effect of CG Shift – SET 2

Correct answer is – Changing of stabilizer trim. – Trim changes only affect aerodynamic forces and stabiliser angle, not the mass or its distribution; hence negligible effect on C of G compared to other options which involve actual mass movement

Correct answer is – At the Neutral point. – Neutral stability occurs when C of G coincides with neutral point where restoring moment is zero; aircraft neither returns nor diverges after disturbance

Correct answer is – Climb gradient. – High temperature and high elevation reduce air density and engine thrust, reducing climb performance; with no obstacle constraints (oceanic), climb gradient becomes the limiting factor for take-off mass

Correct answer is – It would be very sensitive to pitch control inputs and difficult to trim. – With C of G close to aft limit stability is reduced, making the aircraft highly responsive to pitch inputs and harder to maintain trimmed flight condition

Correct answer is – (i), (ii), (iii), (iv) and (v). – Exceeding performance landing mass affects braking, stopping distance and go-around capability causing thermal stress and operational risks but not immediate structural failure

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

Correct answer is – Sufficient fuel must be dumped to reduce mass to be equal to or less than the regulated landing mass. – Regulated landing mass is the limiting value; fuel should be dumped only as required to reach this limit while maintaining safe reserves

Correct answer is – (i), (ii) and (iii). – Increased mass increases LDR and VLOF; forward C of G increases rotation force; minimum control speeds are unaffected and range decreases due increased drag

Correct answer is – Changing of stabilizer trim. – Trim changes only alter aerodynamic forces (stabiliser incidence) and do not change mass distribution, hence negligible effect on C of G

Correct answer is – Decreased take-off and climb performance. – Increased mass increases lift requirement and drag, reducing acceleration, climb gradient and overall performance

Correct answer is – Increase stalling speed. – Higher mass requires greater lift coefficient, raising the minimum speed at which lift equals weight (stall speed)

Correct answer is – Decreases stability making it easier to manoeuvre the aircraft. – Aft C of G reduces static stability, making aircraft more responsive and manoeuvrable but less stable

Correct answer is – Increase trim drag. – Forward C of G increases tail downforce requirement which increases induced drag and reduces efficiency

Correct answer is – It would be very sensitive to pitch control inputs and difficult to trim. – Aft C of G reduces stability, making aircraft highly responsive and requiring continuous trimming to maintain attitude

Correct answer is – Decrease stalling speed. – Lower mass reduces lift requirement allowing flight at lower speeds before stall occurs

Correct answer is – Increase range. – Aft C of G reduces tail downforce and induced drag improving aerodynamic efficiency and range

Correct answer is – Increase stick forces at rotation. – Forward C of G increases nose-down moment requiring greater elevator force to rotate aircraft at take-off

Correct answer is – Decrease range. – Increasing static margin means moving C of G forward, increasing tail downforce and induced drag, which increases fuel consumption and reduces range and endurance

Correct answer is – Increase stalling speed. – Higher mass requires greater lift; with CLmax fixed, this increases the minimum speed at which lift can be generated, thus increasing stall speed

Correct answer is – Decrease stick forces at rotation. – Aft C of G reduces nose-down moment and required tail force, reducing control force required to rotate during take-off

Correct answer is – An increased pitch up attitude any given airspeed. – Increased mass requires higher angle of attack to generate required lift, resulting in higher pitch attitude at same airspeed

Correct answer is – Move the C of G forward. – Static margin is the distance between neutral point and C of G; increasing it implies moving C of G forward, increasing stability but also drag

Correct answer is – Reduce fuel consumption. – Aft C of G reduces tail downforce required, decreasing induced drag and overall drag, which lowers fuel consumption and improves efficiency

Correct answer is – Not affect VMCG. – VMCG depends on engine thrust and control authority and is independent of C of G position; forward C of G mainly increases drag and reduces efficiency

Correct answer is – The aircraft will be more manoeuvrable but may be more difficult to control, because it will be less stable. – Excessively aft C of G reduces stability significantly, making aircraft very sensitive and harder to control despite increased manoeuvrability

Correct answer is – Decreases stability making it easier to manoeuvre the aircraft. – Rearward C of G reduces restoring moment, improving manoeuvrability but reducing stability

Correct answer is – VLOF will be increased. – Higher actual mass increases lift-off speed requirement, but V₁ and Vᵣ are based on calculated mass and remain unchanged

Correct answer is – Sometimes. – Whether within limits depends on factors such as distribution of load, density altitude, runway length and structural/performance limits; full load does not guarantee compliance

Correct answer is – The C of G must be aft of its rear limit. – Neutral stability occurs at the neutral point which lies aft of the allowable C of G range, beyond the rear limit

Correct answer is – An increased angle of attack at any given airspeed. – Increased mass requires greater lift, which is achieved by increasing angle of attack at the same airspeed

Correct answer is – Climb gradient. – High temperature and altitude reduce engine thrust and air density, limiting climb performance even with long runway and no obstacles

Correct answer is – Control will be more difficult because the aircraft will be more stable. – Excessively forward C of G increases stability but reduces control authority, making manoeuvring and pitch control difficult

Correct answer is – Stability requirements and elevator control range. – Forward limit is governed by ability to generate sufficient pitching moment (control authority) while maintaining stability

Correct answer is – Stability and controllability requirements. – Aft limit is governed by maintaining sufficient stability and control; beyond this aircraft becomes unstable and difficult to control

Correct answer is – Gear retraction will move the C of G forward. – Nose gear retracting forward shifts mass forward; main gear effects cancel out

Correct answer is – Decreased climb and take-off performance. – Increased mass increases drag and lift requirement, reducing climb performance and take-off efficiency

Correct answer is – Gear extension will move the C of G forward. – Nose gear extends forward shifting C of G forward while main gear effects cancel

Correct answer is – Decreased take-off performance and endurance. – Increased mass increases drag and fuel consumption, reducing endurance and degrading performance

Correct answer is – It would be very sensitive to pitch control inputs and difficult to trim. – Reduced stability near aft limit makes aircraft highly sensitive and harder to trim

Correct answer is – It would be neutrally statically stable. – At neutral point restoring moment is zero resulting in neutral stability

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

Correct answer is – Sometimes. – Compliance depends on environmental conditions, runway, and performance limits; full load does not guarantee it is within limits