ProSyllabus JournalArmy Officer Selection Board (AOSB), British Army

AOSB Main Board: The Four Days, Test by Test

The AOSB Main Board is a four-day residential assessment at Westbury: tests, essay, interview, lecture, planning exercise and command tasks. The Army's programme, and the Main Board (Short) for PQOs.

Updated 2 weeks agoBritish Army · AOSB · Main Board
#AOSB Main Board#AOSB main board day by day#AOSB lecturette#AOSB command task#AOSB essay#Main Board Short PQO
Practice exercisesFour AOSB planning exercises, worked to the minute
  • The six parts of the Army's answer sheet
  • Four original scenarios, each with a map
  • 20 focused questions with working
  • Two options compared for every exercise
  • A timed plan, a contingency and a justification
  • Briefing and Main Board on one page
₹1,899
Read page 1 freeView details
AOSB Main Board: The Four Days, Test by Test

Checked 21 October 2026. Programme read from the Army officer selection page and the officer, reserve officer and officer training pages, 21 Oct 2026. Check your own joining instructions.

The Main Board is the second stage of the Army Officer Selection Board, and the Army says that once you have passed it you are given an offer of employment for your place at Sandhurst. The Army calls it "a residential assessment" and warns: "You'll need to arrive physically and mentally fit, as the tests will be demanding." For a regular officer candidate, the Army's application page says "The Main Board will last for 4 days." This guide sets out the four days as the Army publishes them, with what you can prepare for each.

4 days
Main Board for regular officer candidates
3 days
Main Board (Short) for PQOs and specialists
5 min
lecture, then questions from the group
8.7
MSFT level the four-day Main Board says candidates should aspire to exceed

British Army Jobs: Army officer selection and Officer Application Process pages, read 21 Oct 2026.

The four days

DayActivityArmy description
Day 1Introductory talk"tips on how to make the most of your trip"
Day 1Psychometric tests"a measure of your cognitive and personality profile"
Day 1Written test"write a short essay on current affairs"
Day 1Multi Stage Fitness test"candidates should aspire to exceed level 8.7, the activity is run up to level 11.6"
Day 2Outdoor tasks"group exercises in practical problem solving that you saw at Briefing"
Day 2Interview"you'll be asked about your experiences and interests, and why you are applying to be an Army officer"
Day 2Tutorial"a reminder of what was covered in the Briefing and a revision period in preparation for the planning exercise"
Day 3Lecture"Give a 5 minute talk and take questions from the group"
Day 3Planning exercise"This is a test of conceptual problem solving. This exercise involves a solo written assessment followed by a group discussion."
Day 3Command task"Outdoor activities where you'll take turns to lead the group"
Day 3Individual Task course"Take on as many tasks as you can within a time limit"
Day 4Final group command task"a series of minor command tasks in sequence that the group complete against other groups on the board"

What you can prepare, test by test

Essay on current affairs (day 1)

  • The Army's tips include "Be aware of current affairs, especially any about society or defence". Our advice: read a quality news source daily in the weeks before.
  • Our advice: practise short essays with a plan first: a clear position, two or three arguments, one counter-argument, a conclusion.

Interview (day 2)

  • The Army names the ground: your experiences and interests, and why you are applying to be an Army officer.
  • Our advice: prepare real examples of responsibility, teamwork and setbacks. An Army tip is to "Research and understand which part of the Army you want to serve in"; our advice is to know why, too.

Lecture (day 3)

  • Five minutes, then questions from the group. Our advice: pick a subject you know well, rehearse to the clock, and practise taking questions you did not expect.

Planning exercise (day 3)

Outdoor, command and individual tasks (days 2 to 4)

  • The outdoor tasks on day 2 are the group problem-solving tasks you saw at Briefing. On day 3 you take turns to lead in the command task, and the individual task course asks you to take on as many tasks as you can within a time limit. Day 4 ends with a final group command task against other groups.
  • Our advice: arrive fit enough that the physical side costs you nothing, so your attention goes on the problem and the people.

"Everyone is able to come here and give it their best. They're looking for your potential, not just whether you're going to be amazing at all things Army. You're not the finished product yet."

Quoted on the Army officer selection page

The lecture: five minutes, planned

The day 3 lecture is five minutes and then questions from the group. Our plan for the five minutes:

PartTime (our plan)What goes in it
Opening0:00 to 0:30The subject, why it matters to you, and the three points you will make.
Point 10:30 to 1:45One idea, one example or fact.
Point 21:45 to 3:00One idea, one example or fact.
Point 33:00 to 4:15One idea, one example or fact.
Close4:15 to 5:00The three points again in one sentence each, and a last line.
Practice exercisesFour AOSB planning exercises, worked to the minute
  • The six parts of the Army's answer sheet
  • Four original scenarios, each with a map
  • 20 focused questions with working
  • Two options compared for every exercise
  • A timed plan, a contingency and a justification
  • Briefing and Main Board on one page
₹1,899
Read page 1 freeView details

Our advice, not an Army rule. Choose a subject you know from experience, such as a sport, an expedition, a job or a hobby, because the questions afterwards are where thin knowledge shows. Rehearse aloud with a timer at least five times, and have a friend ask you three questions you have not prepared for.

The essay: practising current affairs

The Army describes the written test as "write a short essay on current affairs", and its tips point you to "current affairs, especially any about society or defence". Our way to practise: each week, take one news story about society and one about defence, and write a short essay on each to a fixed time limit you set yourself. Begin with a one-line answer to the question, give two or three reasons with facts you can stand behind, deal fairly with the strongest objection, and finish by restating your answer. Keep a page of notes on the stories you read, so that on the day you are writing about subjects you know rather than inventing facts. Read your practice essays back the next day: a claim you cannot support from your notes is one to cut.

Main Board (Short) for PQOs and specialists

If you are joining as a Professionally Qualified Officer or specialist, the Army says you attend a three-day short programme that "includes elements from the Briefing to help you prepare as much as possible for the assessments."

DayProgramme
Day 1Introductory talk; an item the page lists only as "Briefing Phrase."; psychometric tests (as practised online through a link provided ahead of attendance); tutorial on practical tasks and leaderless tasks; practice of the MSFT; planning exercise tutorial; interviews with specific Arms and Services (for RAChD only)
Day 2Group discussion with a 2 minute introduction by each candidate; short essay; 5 minute lecturette; interviews; leaderless tasks; the planning exercise (solo written assessment, then group discussion)
Day 3Undertake practical tasks: MSFT (aspire to reach level 8.7, run up to level 11.6) and a command task

The Army also describes the Army Scholarship Board, which runs over three days with its own programme, including two interviews on day 2 and a planning exercise on day 3; it says the scholarship board's activities are designed so that you "do not require any rehearsal or pre-board training". For Army Reserve officers, the Reserve Officer Application Process page says you will be "tested mentally and physically over 3 1/2 days" at the Main Board.

After you pass

The Army's application page: once you have passed, you are given an offer of employment for your place at Sandhurst, and the Army still runs some background checks. Once you have accepted, you go on a pre-commissioning course before you can start, where you learn more about the course, have a medical and are given some of your uniform; after it you start the Sandhurst course. That page gives the Sandhurst course as 44 weeks; the officer training page gives 42 weeks of training. If the figure matters to your plans, confirm it with your recruiter. There are three yearly officer intakes, January, May and September, and the Army says it can take around six months from application to starting at Sandhurst.

Main Board preparation tracker

Tick each item when it is done. Each one supports a Main Board test or your general preparation.

0 of 11 done

Day 1 (0/3)
Day 2 (0/2)
Day 3 (0/4)
Day 4 and throughout (0/2)

Ticks are saved only in this browser on this device.

Frequently asked questions

How long is the AOSB Main Board?

The Army says the Main Board lasts 4 days for regular officer candidates. Professionally Qualified Officers and specialists attend a 3-day Main Board (Short), and the Reserve Officer Application Process page says reserve candidates are tested mentally and physically over 3 1/2 days at the Main Board.

What is the AOSB lecturette?

On Main Board day 3 you give a 5 minute talk and take questions from the group. On the Main Board (Short) it is a 5 minute lecturette on day 2.

What MSFT level do I need at Main Board?

The officer pass level is MSFT level 7.10. On the four-day Main Board the Army says candidates should aspire to exceed level 8.7; on Main Board (Short) it says aspire to reach level 8.7. The activity is run up to level 11.6 on both.

Is there an essay at AOSB?

Yes. On day 1 of the Main Board you write a short essay on current affairs.

What happens on the last day of the Main Board?

On the four-day Main Board, day 4 is the final group command task: a series of minor command tasks in sequence that the group completes against other groups on the board. Main Board (Short) lasts three days; its day 3 is the MSFT and a command task.

Do I lead a task at the Main Board?

Yes. In the day 3 command task you take turns to lead the group in outdoor activities. The day 2 outdoor tasks are group exercises in practical problem solving.

How long is the course at Sandhurst after AOSB?

The Army's officer application page says 44 weeks; its officer training page says 42 weeks of training. If the figure matters to your plans, confirm it with your recruiter.

ProSyllabus is an independent study site, not part of the British Army or the Ministry of Defence. The programme and rules here are taken from the Army's own recruitment pages; check anything that matters to you with your recruiter and the joining instructions for your board.

Practice exercisesFour AOSB planning exercises, worked to the minute
  • The six parts of the Army's answer sheet
  • Four original scenarios, each with a map
  • 20 focused questions with working
  • Two options compared for every exercise
  • A timed plan, a contingency and a justification
  • Briefing and Main Board on one page
₹1,899
Read page 1 freeView details

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