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DGCA Air Navigation · 202 questions

Payload, Fuel & Weight and Balance: DGCA Air Navigation Questions and Answers

202 practice questions on Payload, Fuel & Weight and Balance with answers and explanations, plus the key concepts and formulas, from the TrueHeading question bank.

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About this topic

Use this page to revise Payload, Fuel & Weight and Balance for the DGCA Air Navigation paper. Below are the key ideas first, then 12 practice questions with answers and explanations, picked from the 202 questions in the TrueHeading bank for this topic.

In short: Take moments about a datum and divide by total mass.

Open the full set in the student zone to answer every question, track your accuracy and take timed mock tests.

Key concepts: Payload, Fuel & Weight and Balance

7 ideas to know cold.

How do you find the centre of gravity?

Take moments about a datum and divide by total mass.

CG=∑(mass×arm)∑mass\text{CG}=\frac{\sum(\text{mass}\times\text{arm})}{\sum\text{mass}}
  • Moment = mass × arm
  • Arm is measured from the datum, positive aft
  • Check the CG lies inside the envelope for every loading
W1W2W3Datumarm₂CGCG = Σ(weight × arm) ÷ Σ weight

How far does the CG move when you shift cargo?

The shift equals mass moved times distance moved, over total mass.

CG shift=mmoved×dMtotal\text{CG shift}=\frac{m_{moved}\times d}{M_{total}}
  • Moving mass aft moves the CG aft; forward moves it forward
  • The shift is always in the direction the mass moved

Aircraft mass terms in order?

Build up from the empty aircraft:

  • Basic empty mass (structure, systems, unusable fuel)
  • Operating empty mass = basic empty + crew, catering, fluids
  • Zero fuel mass = operating empty + payload
  • Take-off mass = zero fuel + fuel
  • Landing mass = take-off mass − trip fuel

Tip: Each has a maximum: MZFM, MTOM (structural or performance limited), MLM.

What does an aft or forward CG do to handling?

A forward CG makes the aircraft more stable but nose-heavy; an aft CG makes it less stable.

  • Forward CG: higher stall speed, more trim drag and fuel burn, heavier elevator forces
  • Aft CG: lower stall speed, longer range, but reduced stability and recovery risk
  • Beyond the aft limit the aircraft may be impossible to recover from a stall

What is included in the fuel plan for a flight?

ICAO Annex 6 requires taxi, trip, contingency, alternate and final reserve fuel.

  • Contingency: typically 5 % of trip fuel
  • Alternate: to the destination alternate
  • Final reserve: 30 min for turbine engines (at holding speed, 1500 ft above the aerodrome) or 45 min for piston engines
  • Extra fuel at the commander’s discretion

How do you find the centre of gravity of a loaded aeroplane?

Take moments about the datum: CG = total moment / total mass.

CG=∑(m×arm)∑mCG=\dfrac{\sum(m\times\text{arm})}{\sum m}
  • Moment = mass × arm
  • Adding mass behind the CG moves it aft
  • Shifting mass forward moves the CG forward by (mass × distance)/total mass

Define the main aeroplane weights.

BEM (basic empty mass) + payload = zero fuel mass; + fuel = take-off mass.

  • ZFM = DOM + payload
  • RTOM = ramp mass − taxi fuel
  • Landing mass = take-off mass − trip fuel
  • Structural limits: MZFM, MTOM, MLM

Practice questions: Payload, Fuel & Weight and Balance

Tap “Show answer” after you have tried each one.

Q1Usable fuel on board is 9500 kg and the fuel flow is 450 kg/h. How long can the aircraft fly if a final reserve of 45 minutes must remain?

  1. 28h 30min
  2. 20h 22min
  3. 22h 24min
  4. 32h 35min
Show answer

Answer: B. 20h 22min

Total endurance 1267 min, minus 45 min reserve = 1222 min.

Q2Usable fuel on board is 5000 kg and the fuel flow is 2800 kg/h. How long can the aircraft fly if a final reserve of 30 minutes must remain?

  1. 01h 36min
  2. 01h 29min
  3. 01h 17min
  4. 01h 06min
Show answer

Answer: C. 01h 17min

Total endurance 107 min, minus 30 min reserve = 77 min.

Q3The trip distance is 900 NM at a groundspeed of 240 kt with a fuel flow of 1500 kg/h. The trip fuel is:

  1. 3375 kg
  2. 5625 kg
  3. 7031 kg
  4. 6469 kg
Show answer

Answer: B. 5625 kg

Time 3.75 h × 1500 kg/h = 5625 kg.

Q4The trip distance is 850 NM at a groundspeed of 200 kt with a fuel flow of 2600 kg/h. The trip fuel is:

  1. 6630 kg
  2. 12707 kg
  3. 11050 kg
  4. 8288 kg
Show answer

Answer: C. 11050 kg

Time 4.25 h × 2600 kg/h = 11050 kg.

Q5Loading: Basic empty aeroplane 850 kg at 1.0 m; Pilot and front passenger 140 kg at 0.94 m; Rear passengers 60 kg at 1.85 m; Baggage 0 kg at 2.4 m; Fuel 120 kg at 1.2 m. The centre of gravity position (from the datum) is:

  1. 1.06 m
  2. 1.16 m
  3. 0.96 m
  4. 1.26 m
Show answer

Answer: A. 1.06 m

Total mass 1170 kg; total moment 1236.6 kg·m; CG = 1236.6 ÷ 1170 = 1.06 m.

Q6Loading: Basic empty aeroplane 850 kg at 1.0 m; Pilot and front passenger 160 kg at 0.94 m; Rear passengers 0 kg at 1.85 m; Baggage 0 kg at 2.4 m; Fuel 100 kg at 1.2 m. The centre of gravity position (from the datum) is:

  1. 0.91 m
  2. 1.11 m
  3. 1.01 m
  4. 1.16 m
Show answer

Answer: C. 1.01 m

Total mass 1110 kg; total moment 1120.4 kg·m; CG = 1120.4 ÷ 1110 = 1.01 m.

Q7Maximum take-off mass 5700 kg, basic empty mass 3135 kg, fuel load 684 kg. The maximum payload (take-off mass limited) is:

  1. 1411 kg
  2. 1599 kg
  3. 1129 kg
  4. 1881 kg
Show answer

Answer: D. 1881 kg

Payload = 5700 − 3135 − 684 = 1881 kg.

Q8Aircraft: basic mass 1100 lb at arm 35.0 in; front seat 190 lb at 37 in; rear seat 130 lb at 73 in; baggage 20 lb at 98 in; fuel 240 lb at 48 in. The CG position is:

  1. 43.2 in
  2. 40.8 in
  3. 58.2 in
  4. 39.6 in
Show answer

Answer: B. 40.8 in

Moments: 1100×35.0=38500; 190×37=7030; 130×73=9490; 20×98=1960; 240×48=11520. Total moment 68500 ÷ total mass 1680 = 40.8 in.

Q9Aircraft: basic mass 900 lb at arm 34.5 in; front seat 160 lb at 38 in; rear seat 110 lb at 75 in; baggage 35 lb at 100 in; fuel 290 lb at 46 in. The CG position is:

  1. 40.3 in
  2. 58.7 in
  3. 41.6 in
  4. 44.0 in
Show answer

Answer: C. 41.6 in

Moments: 900×34.5=31050; 160×38=6080; 110×75=8250; 35×100=3500; 290×46=13340. Total moment 62220 ÷ total mass 1495 = 41.6 in.

Q10An aircraft of mass 60000 kg has a mass of 200 kg moved 20 m forward. The CG moves forward by approximately:

  1. 0.03 m
  2. 0.18 m
  3. 0.07 m
  4. 0.13 m
Show answer

Answer: C. 0.07 m

Shift = mass moved × distance ÷ total mass = 200 × 20 ÷ 60000 = 0.07 m.

Q11Usable fuel is 7000 kg and the average fuel flow is 3000 kg/h. The endurance is:

  1. 2 h 37 min
  2. 2 h 20 min
  3. 2 h 03 min
  4. 31 min
Show answer

Answer: B. 2 h 20 min

Endurance = fuel ÷ fuel flow = 7000 ÷ 3000 = 2.33 h = 2 h 20 min.

Q12A trip of 1400 nm is flown at a ground speed of 480 kt with a fuel flow of 2000 kg/h. The trip fuel is:

  1. 4 667 kg
  2. 2 800 kg
  3. 5 833 kg
  4. 7 000 kg
Show answer

Answer: C. 5 833 kg

Time = 1400/480 = 2.92 h. Fuel = 2.92 × 2000 = 5 833 kg.

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