Free screening tool

Is your movement level supported by the arrangements you have?

Seventeen questions about how your aerodrome actually runs on a busy day. You get a weighted advisory result, the sections carrying most of the exposure, and a separate screen for change and open hazards. It takes about ten minutes and runs entirely in your browser.

Who it is for

Operators, safety managers, flying schools and clubs at smaller aerodromes without a full air traffic service, where circuit traffic, training and mixed activity share the same airspace and the same runway.

What you get

A weighted result out of 100, a ranked view of which sections carry the exposure, and a separate reading of the change and unresolved-hazard screen that the ranking is not allowed to smooth over.

What it is not

It does not calculate a movement number, and no result here permits, limits or supports any traffic figure. Two sites with identical movement counts can land in different bands, because the score is about arrangements rather than counts.

Before you start

Answer for how the operation runs in practice on a busy day, not for what the documents say should happen. If the published pattern is not the one flown when four aircraft are in the circuit, answer for the one that is flown. Where you genuinely do not know, choose Not known rather than guessing; the tool treats that as a finding in its own right.

Do not enter confidential, personal or operator-identifying information. Nothing is submitted anywhere until you choose to send a summary, and the questions are written so that you never need to name a person, an operator or an occurrence.

0 of 17 questions answered

Section A · 24 of 100 pointsTraffic demand, peaks and activity mix

How much traffic the site has to absorb, how tightly it bunches into peak hours and bursts, and how many different kinds of activity can be moving at once.

Q1 · Simultaneity in the circuit · 7 pointsHow often does the number of aircraft operating in the circuit and the immediate arrival area at the same time reach the level your local arrangements were built around?
Q2 · Peak concentration · 6 pointsHow concentrated is your traffic into peak days, peak hours and quarter-hour bursts rather than spread across the operating day?
Q3 · Activity mix overlap · 6 pointsWhich activity types can be airborne or moving on the manoeuvring area at the same time as your normal circuit traffic?
Q4 · Movement data reliability · 5 pointsHow reliable are the movement counts, activity types and peak figures you would use to describe your traffic level to somebody else?
Section B · 28 of 100 pointsCircuit, airspace and radio arrangements

The arrangements that absorb that demand in the air: whether the published pattern is actually flown, whether the radio picture holds up when it is busy, and what happens when an unexpected aircraft turns up.

Q5 · Circuit discipline in practice · 8 pointsHow consistently do pilots actually fly the published circuit, entry and departure pattern when the airfield is at its busiest?
Q6 · Radio picture when busy · 7 pointsHow dependable is the traffic picture built on your local frequency during the busiest hour of a normal week?
Q7 · Unexpected joining traffic · 7 pointsWhat happens when an aircraft nobody expected joins the circuit while it is already carrying its normal busy-day load?
Q8 · Electronic conspicuity uptake · 6 pointsHow much of your regular traffic carries and uses electronic conspicuity that other local aircraft can actually see?
Section C · 16 of 100 pointsRunway occupancy and surface throughput

How long each aircraft ties up the runway and the movement area, and whether taxi, entry and parking arrangements keep up when several aircraft arrive together.

Q9 · Runway occupancy · 6 pointsHow long does a typical landing aircraft stay on your runway before it is fully clear, and what drives that time?
Q10 · Ground conflict exposure · 5 pointsHow exposed is your movement area to taxi, vehicle and runway-entry conflict during the busiest flying periods?
Q11 · Apron and parking absorption · 5 pointsHow well do apron, parking and refuelling arrangements absorb your busiest arrival period without aircraft waiting on the taxiway?
Section D · 26 of 100 pointsService level, oversight and monitoring

Who is watching the traffic situation while flying is going on, what they are able to do about it, and how the accepted traffic level is re-examined when the level of service or the volume changes.

Q12 · Who is watching · 7 pointsWho is actually watching the traffic situation while flying is going on, and what are they able to do about it?
Q13 · Service level versus volume · 7 pointsWhen your level of service or your traffic volume last changed materially, how was the traffic level you accept re-examined against the arrangements that remained?
Q14 · Trigger thresholds · 6 pointsWhat traffic level triggers a defined response at your site, and what actually happens once it is reached?
Q15 · Occurrence trend review · 6 pointsHow are local occurrences, near misses and airprox reports used to test whether your current traffic level still works?
Section E · 6 of 100 pointsChange and unresolved-hazard screen

These two questions are handled separately from the score and are shown on their own, because a material unassessed change or an open serious hazard cannot be offset by strong answers anywhere else in the tool.

Q16 · Material change · 4 pointsWhat material change to traffic volume, activity mix, level of service, procedures, infrastructure or operating hours has taken place or is planned?
Q17 · Unresolved hazard screen · 2 pointsWhat known serious or unresolved hazard, recent occurrence trend or barrier failure is currently open at your site?

Nothing is sent when you calculate. The scoring happens in your browser.

Your result

Answer all 17 questions above, then choose Show my result.

Send this to NorthSky

If the result points somewhere you were not expecting, a short conversation about it is usually more useful than a second run through the tool.

You can send the summary to NorthSky with a note about what prompted the screening. A full assessment of a movement level is a different job: it means looking at your real traffic data and peaks, working through circuit simultaneity and runway occupancy for your layout, testing the barriers you actually rely on, and documenting the reasoning so it stands up when somebody asks. This tool tells you where to look. It does not tell you what your site can carry.

Your answers stay in your browser unless you choose to send a summary. What happens to a summary you do send is described at /tools/privacy/.

NorthSky — Safe movement numbers submissions

Common questions

Does this tool tell me how many movements my aerodrome can safely handle?

No, and it is built so that it cannot. It screens whether the movement level you already have is supported by the arrangements you already have. A number produced without your traffic data, your layout, your runway occupancy and your barriers would be misleading, and no result here permits, limits or supports any figure.

Why can two aerodromes with the same movement count get different results?

Because the movement count is only the demand side. What matters is whether the circuit is flown as published, whether the radio picture holds up in a busy hour, how long each aircraft ties up the runway, and whether anyone on the ground can slow things down. Identical counts under different arrangements are genuinely different situations.

Our traffic went up while our level of service went down. How does that show up here?

That combination is exactly what the fourth section asks about, and it is one of the patterns that raises the advisory band on its own. The same movement figure carries a different exposure once traffic information, structured flow or a named person watching the traffic is no longer there to absorb it.

Is the runway usually the limiting factor?

At smaller aerodromes it often is not. Runway throughput tends to be well above the demand, and the binding constraint is more often how many aircraft a pilot can keep track of in the circuit at once. The runway becomes decisive where a long backtrack or a single exit keeps it occupied while another aircraft is on final.

What happens if we answer "Not known" to several questions?

Those answers are scored at the top of the range and they also raise a separate finding. That is deliberate rather than punitive: if you cannot say how concentrated your peaks are, how reliable your movement counts are, or who is watching the traffic, then any discussion about your traffic level is being held without its foundations.

Can we use the result in a safety case or a licence application?

Not as evidence. It is an advisory screening based only on what you typed, and it does not assess certification, licensing or authority requirements. It is useful earlier than that: as a way of finding out which parts of your operation a proper assessment will need to spend its time on.

How is the weighting decided?

By professional judgement about where the real exposure sits at aerodromes of this kind, informed by public capacity and non-towered operating guidance and by the pattern of occurrences at sites where traffic grew faster than the arrangements around it. Version 0.9 is not yet calibrated against completed assessments, and the weighting will move as it is.

Scope of NorthSky’s work

NorthSky provides operational risk decision support and advisory guidance. Outputs do not constitute regulatory certification, aerodrome licensing, compliance verification, or formal authority determinations.

How this tool scores

Each question carries a weight. The four ranked sections carry 24, 28, 16 and 26 points, and the change and unresolved-hazard screen carries the remaining 6, so the five sections add to 100. The first section measures demand: how much traffic, in what mix, at what peaks. The other three measure the arrangements that have to absorb it. That is deliberate, because a site can be safe at a high movement number and exposed at a low one, and the score is designed to say which of those you look like.

This is model version 0.9. The weighting is a considered professional judgement, not yet calibrated against completed assessments, so treat the band as a prompt for the right conversation rather than a measurement. The change and unresolved-hazard questions are reported separately and can raise the advisory band on their own, because a strong answer about radio discipline does not close an unassessed change.

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