031 ATPL subject guide
Mass and Balance
Mass and Balance is compact compared with the biggest ATPL subjects, but it can still cost marks if your calculation method is untidy. Clean, repeatable working matters more than speed alone.
Difficulty
Medium
What the paper tests
Calculation-focused with repeated patterns
Why it matters
The exam expects you to convert loading information into safe centre-of-gravity decisions, not just plug numbers into formulas without understanding what they mean operationally.
Best next step
Use timed practice and spaced recall together so weak areas come back before they decay.
Key topics
- Centre-of-gravity calculations and movement
- Load and trim sheet interpretation
- Payload, fuel, and envelope limitation trade-offs
How to study it
- Use one standard calculation layout for every practice question so you reduce arithmetic mistakes.
- Practise reading diagrams and envelopes, not just doing the arithmetic.
- Review unit conversions and sign direction carefully when mass shifts forward or aft.
Common traps
- Rushing arithmetic because the formulas look simple.
- Ignoring the operational meaning of moving CG forward or aft.
- Losing marks on unit conversions or moment indexing conventions.
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Open subject guideFree tools for this subject
Practise what Mass and Balance tests, free and without an account.
Free tool
Aviation Unit Converter
Drill the conversions Mass and Balance hides inside its numbers: litres and gallons to kilograms through a fuel density, and kilograms to pounds without sign slips.
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Practice Mass and Balance questions
Exam-style 031 Mass and Balance questions with explanations, spaced repetition, and timed mock exams. Free to start.
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SkyStudy combines ATPL practice questions, mock exams, spaced repetition, and progress tracking so subject knowledge turns into exam performance instead of staying as passive reading.
This page is general educational information for student pilots and may be out of date. Aviation rules, training requirements, costs, medical standards, and exam details change over time and vary by country, authority, and training organisation, so details here may no longer be current or may differ in your case. Always confirm the current details with your approved training organisation (ATO) and national aviation authority before relying on them. SkyStudy is an independent study aid, is not affiliated with EASA or any aviation authority, and does not guarantee any exam or licence outcome.
Last reviewed July 2026