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UK CAA ATPL(A) · Subject 031

ATPL Mass and Balance practice questions

Mass and Balance (031) covers mass limits, loading, centre of gravity calculations and load sheets, using the MRJT data in CAP 696. Most questions are calculations: finding the maximum take-off or landing mass, the CG position as a percentage of MAC, and how far cargo must move to bring the CG within limits.

29original questions here
25questions in the practice paper
1 hour 15 minutestime allowed
Start a timed 031 paper Try sample questions

Free, no sign-up. The practice paper uses the question count and time limit from CAA guidance for this subject. Check the CAA for the current figures before your exam.

About the exam

What to expect in 031 Mass and Balance

It is a short paper and one of the most methodical. The marks come from working accurately and spotting which limit governs, rather than from memorising facts.

In the practice desk you can sit a full 25-question paper under exam conditions, or drill one syllabus topic at a time. Questions you miss come back after 1, 3, 7, 16 and 35 days, so weak areas get repeated until they stick.

Syllabus

031 syllabus topics

Every topic below has practice questions, and you can drill any of them on its own.

  • 031 01Purpose of Mass and Balance Considerations · 4 questions
  • 031 02Loading · 6 questions
  • 031 04Mass and Balance Details of Aircraft · 5 questions
  • 031 05Determination of CG Position · 11 questions
  • 031 06Cargo Handling · 3 questions
Try it

Sample ATPL Mass and Balance questions

Five questions from the bank. Each one in the practice desk has a worked explanation like these.

Sample 1 · 031 01 · Purpose of Mass and Balance Considerations

An aeroplane is loaded so that its centre of gravity is forward of the forward limit. Which of the following is the most likely consequence?

  1. AReduced trim drag and a longer range
  2. BLighter stick forces and a tendency to over-rotate on take-off
  3. CA lower stall speed and reduced longitudinal stability
  4. DA higher stall speed and too little elevator authority to flare
Show the answer

Answer: D. A higher stall speed and too little elevator authority to flare

A forward CG needs more tail download, so the wing must make more lift and the stall speed rises. Beyond the forward limit the elevator may run out of authority at low speed, during rotation or the flare.

Common trap: Swapping forward-CG and aft-CG effects. Forward: stable, heavy, high stall speed. Aft: less stable, light, low stall speed.

Sample 2 · 031 05 · Determination of CG Position

An aeroplane has a mass of 5 200 kg with the CG 3.10 m aft of the datum. A 150 kg load is added at 4.60 m aft of the datum. What is the new CG position?

  1. A3.85 m aft of datum
  2. B3.14 m aft of datum
  3. C3.06 m aft of datum
  4. D3.23 m aft of datum
Show the answer

Answer: B. 3.14 m aft of datum

New total moment ÷ new total mass.

Common trap: Dividing by the old mass. Every time mass is added or removed the total mass changes.

Sample 3 · 031 02 · Loading

An aeroplane is refuelled with 5 000 US gallons of fuel with a specific gravity of 0.79. What mass of fuel has been loaded?

  1. A17 957 kg
  2. B14 951 kg
  3. C32 960 kg
  4. D23 956 kg
Show the answer

Answer: B. 14 951 kg

US gallons to litres, then litres × specific gravity gives kg.

Common trap: Confusing US and imperial gallons, or multiplying when you should divide.

Sample 4 · 031 04 · Mass and Balance Details of Aircraft

Which item is included in the dry operating mass of a transport aeroplane?

  1. AUsable fuel
  2. BCargo and mail
  3. CPassenger baggage
  4. DPotable water and lavatory chemicals
Show the answer

Answer: D. Potable water and lavatory chemicals

Potable water and lavatory chemicals are part of the dry operating mass.

Common trap: Putting usable fuel in the DOM. Usable fuel turns DOM into operating mass.

Sample 5 · 031 06 · Cargo Handling

A 400 kg item is to be loaded in the forward cargo compartment of MRJT1, between balance arms 228 and 286 in. What is the minimum length over which the item must be spread so that the running load limit is not exceeded? Refer to CAP 696 Section 4, Figure 4.9 in your own copy of the manual.

  1. A47.2 in
  2. B5.9 in
  3. C30.4 in
  4. D2.5 in
Show the answer

Answer: C. 30.4 in

Running load limit for that section is 13.15 kg per inch.

Common trap: Mixing up running load (per inch) and area load (per square foot).

Practise all 29 031 questions
Revision tips

How to revise Mass and Balance

  • Always write out the three take-off limits (structural, performance and landing plus trip fuel) and take the lowest.
  • Keep a consistent sign convention for arms and moments, and check your answer is inside the envelope before choosing it.
  • Use your own copy of CAP 696 every time you practise, so finding the right page is automatic on the day.
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