Running Memory Span Test: Format, Examples, Preparation

The running memory span test is one of the most feared parts of pilot and ATC selection, and also one of the most trainable. A voice reads a stream of digits, you never know when it will stop, and the moment it does you must enter the last few digits in reverse order. This guide breaks down the exact format, the scoring logic, and the preparation methods that genuinely raise your span.

What is the Running Memory Span Test?

The running memory span test measures your working memory: the mental workspace where you hold and manipulate information that is still changing. It appears in DLR-style pilot screenings and in ATC selection batteries, because both jobs demand exactly this skill. A pilot rereads a clearance while flying the aircraft. A controller holds three callsigns in mind while a fourth checks in.

Unlike a classic digit span task, where you know in advance how many digits are coming, the running version keeps the length secret. The stream might stop after six digits or after fourteen. That single change transforms the task: you cannot simply memorize from the start, because your memory would overflow long before the voice stops. Instead you must maintain a rolling window of the most recent digits and continuously discard the old ones.

When the voice stops, you enter the last digits you remember in reverse order. The last digit you heard becomes the first one you type.

Which Exams Include the Running Memory Span Test?

Memory span tasks in this running, reverse-entry format are among the most widely used items in aviation selection. Candidates commonly report meeting this test type in:

• DLR screenings (German Aerospace Center, used by Lufthansa Group and other European carriers)
• COMPASS and Advanced COMPASS by EPST, common across European flight academies
• PACE, used in several airline and cadet programme assessments
• ADAPT, part of many airline and academy screening pipelines
• Aon / cut-e batteries, used by a large number of airlines worldwide
• FEAST and related ATC selection batteries, where working memory items serve the same purpose

Providers update their test content regularly and none of them publish an official syllabus, so treat this list as candidate-reported guidance rather than a guarantee. What does not change is the underlying skill: if your rolling memory window is trained, the exact branding on the test matters very little.

How the Test Works: Format and Rules

The structure is simple to describe and hard to do:

• Digits are read aloud, one at a time, at a fixed pace. Headphones are strongly recommended.
• You never know how many digits will come. Streams vary in length within the same session.
• When the stream stops, an input screen appears.
• You enter the final digits in reverse order: last heard, first entered.
• Accuracy beats speed. The input phase is not the timed part; the listening is where the test is won or lost.

A quick example. Suppose the voice reads: 4, 1, 9, 6, 3, 8, then stops. If the task asks for the last three digits, the correct entry is 8, 3, 6. You heard "...6, 3, 8" and you type it back mirrored. This is exactly how it looks in the test:

Difficulty rises across levels in two ways: the digits come faster and the recall window grows. In our training module the progression looks like this:

1. Level 1: sequences start at 3 digits, 800 ms per digit
2. Level 2: 4 digits, 700 ms per digit
3. Level 3: 5 digits, 600 ms per digit
4. Level 4: 6 digits, 520 ms per digit
5. Level 5: 7 digits, 450 ms per digit

By the top levels you are updating your mental buffer roughly twice per second while preparing to reverse it on demand.

You are not asked to remember everything you heard. You are asked to let go of everything except the tail.

Scoring: What a Good Result Looks Like

Scoring is based on the digits you place correctly, position by position. Entering 8, 3, 5 when the answer was 8, 3, 6 still earns credit for the first two positions. This matters for strategy: a partially correct answer is always better than a frozen one. If you are unsure about the deepest digit, enter your best guess and protect the digits you are sure of.

Selection benchmarks vary by airline and academy, but as a rule of thumb, consistently reversing the last 4 digits under fast presentation puts you in solid territory, and a reliable 5 to 6 digit window is a strong result. The real differentiator is consistency across a long session, because assessors read your worst trials as closely as your best ones.

How to Prepare: Strategies That Actually Work

Working memory capacity itself is stubborn, but performance on this task responds very well to technique and practice. Focus on these:

1. Train the rolling window. Practice holding only the last 3 or 4 digits and deliberately dropping everything older. The skill you are building is controlled forgetting, not bigger memory.
2. Use rhythmic subvocal rehearsal. Repeat the current tail silently in a steady rhythm as new digits arrive: "9, 6, 3... 6, 3, 8". Your inner voice is the most reliable buffer you have.
3. Reverse at entry, not while listening. Do not try to maintain a reversed copy during the stream; it doubles your load. Hold the tail in heard order, then flip it once the voice stops.
4. Short daily sessions beat marathons. Ten focused minutes a day for three weeks outperforms a three hour session the weekend before your assessment.
5. Raise one difficulty axis at a time. First get comfortable at a faster pace, then extend the window length. Jumping both at once teaches panic, not capacity.
6. Match test conditions. Train with headphones, sitting upright, no second screen. Familiarity with the exact sensory setup removes a layer of stress on the day.

Common Mistakes to Avoid

• Trying to memorize the stream from the first digit. The stream is designed to overflow you.
• Entering digits in heard order instead of reversed. Drill the flip until it is automatic.
• Freezing when the voice stops earlier than expected. Early stops are part of the design; treat every digit as if it might be the last.
• Practicing only at slow speeds. Comfort at 800 ms does not transfer to 450 ms by itself.

Practice This Skill

Reading about working memory does not build it; reps do. The best preparation is running the real format until the reversal feels mechanical: train with the Running Memory Span module, which reproduces the audio stream, the surprise stops and the reverse entry exactly as described here. Level 1 is free, and a guided tutorial walks you through the format before your first attempt.