Airspace Flow & Sector Delay Analyzer

Model tactical air traffic control bottlenecks, sector acceptance reductions (AAR), holding stacks, and oceanic reroutes in real-time when key flight control centers face degradation.

SECTOR SCOPE: EGPX / SCOTLAND & N-ENGLAND
FLOW REGIME: RESTRICTED (GDP-01)
SIM UTC: 14:28:10 Z
RADAR REFRESH: 1.0s REALTIME
Average Delay 48 min Across active movements
In Holding Pattern 7 ac Burn rate: +4,200 kg/hr
Active Reroutes 11 ac Via Shannon / Irish Sea
Compensation Risk £142k >3h UK261 Threshold

Tactical Flight Sequence Log

Tracking 42 flights
Callsign Type Origin → Dest Sector Holding Fix Delay (Min) Tactical Action
System ready. Scottish FIR capacity constrained at 35% AAR.

Understanding ATC Outages & Sector Metering

When an en-route control center (such as NATS Prestwick Centre or London AC at Swanwick) suffers technical degradation or flight-data processing failure, controllers must transition from automated spacing tools to manual radar procedural separation.

  • Sector Acceptance Rate (AAR): The safe hourly ceiling of aircraft permitted into an airspace volume. In severe outages, AAR drops by 50% to 80%.
  • Miles-in-Trail (MIT): Spacing buffers increased from standard 5 NM up to 30–50 NM along oceanic waypoints (e.g., RATSU, GOW, TRN).
  • Ground Delay Programs (GDP): Holding outbound aircraft on the tarmac at departure airports to avoid saturating en-route holding stacks.

Airspace Flow Management FAQ

Why does a Scottish FIR glitch ground flights across the UK?

Prestwick Centre controls Scottish airspace, Northern Ireland, northern England, and the Shanwick Oceanic transition into the North Atlantic tracks. Any stoppage blocks both domestic trunk corridors and transatlantic arrivals.

What is the difference between Holding and Rerouting?

Holding keeps aircraft in oval racetrack patterns over specific navigation fixes until a sector slot opens. When holding fuel limits are approached, flow management directs aircraft west via Irish airspace or east over the North Sea.

Are airlines liable for UK261 compensation during ATC technical issues?

ATC system failures are typically classified as "extraordinary circumstances," relieving airlines of statutory cash compensation if all reasonable rerouting measures were taken, though duty of care (meals, accommodation) remains mandatory.

When the sky narrows: how a sector outage turns into holding stacks and detours

A one-minute painted explainer of how this planner turns a cut in sector capacity into reroutes, holding and fuel burn, followed by how real flow managers handle it.

Read the narration

When an air traffic control centre has a technical failure, the sky doesn't close. It narrows. This planner models what happens when Scottish upper airspace loses most of its capacity. Normally that sector accepts thirty-eight aircraft an hour. In the default outage, the tool cuts it to fourteen, about thirty-seven percent of normal. Every flight that starts or ends at Edinburgh, Glasgow, Belfast, or the oceanic entry point is counted in that sector. That's roughly four in every five of the forty-two simulated flights. With the bypass switched on, about half of them are sent around through Irish airspace. Each detour costs twenty-two minutes, plus four tenths of a minute per mile of spacing. At thirty miles in trail, that's thirty-four minutes. The rest circle in holding stacks, because acceptance is below twenty an hour. The tool adds six hundred fifty kilograms of fuel burn per hour for every aircraft in the stack. Real flow managers prefer to hold flights on the ground, where waiting burns no fuel. Try raising the acceptance rate to twenty, and watch the holding stack empty.

What the planner assumes, and how real flow management works

Capacity is a rate, not a wall

The planner gives Scottish Upper a nominal 38 aircraft an hour and the outage scenario 14 (37%). Below 60% of nominal it flags the sector as restricted; below 20 an hour, every sector flight that isn't rerouted is sent to hold.

The tool's delay rules

A rerouted flight's delay is set to at least 22 minutes plus 0.4 minutes per nautical mile of miles-in-trail spacing (34 minutes at the default 30 NM). Each holding aircraft adds 650 kg/hr to the fuel-burn readout. These are the tool's illustrative assumptions, not operational figures.

Ground delay beats airborne holding

Traffic managers use ground delay programs (FAA) and ATFM departure slots (EUROCONTROL's Network Manager) so that aircraft wait at the gate with engines off rather than burning fuel in a stack.

Holding patterns have standard shapes

In the FAA's Aeronautical Information Manual, a standard holding pattern uses right turns with one-minute inbound legs at or below 14,000 ft MSL and one-and-a-half-minute legs above it.

Compensation is not automatic

Delays caused by air traffic control problems are generally treated as extraordinary circumstances under UK261, so cash compensation is usually not owed, though airlines must still provide care. The tool's 'Compensation Risk' figure counts every 3-hour delay anyway, so read it as a worst-case ceiling.

Try it in the tool

  1. Click 'Prestwick Tech Glitch', then drag the Acceptance Rate (AAR) slider from 14 up to 20 and watch the In Holding Pattern count drop to zero.
  2. Slide Miles-In-Trail (MIT) Spacing from 30 NM to 50 NM: rerouted flights in the Tactical Flight Sequence Log jump from +34m to +42m.
  3. Press 'Cancel Sector Bypass' and see every Scottish flight move into the holding stack instead of the Irish Sea corridor.
  4. Click 'Nominal Normal Flow' to restore full capacity and compare the KPI strip.

Sources and further reading

  1. Aeronautical Information Manual, Chapter 5 Section 3: En Route Procedures (Holding) · Federal Aviation Administration

    Standard holding pattern shape and leg timing.

  2. Order JO 7210.3, Facility Operation and Administration (Chapter 17: Traffic Management) · Federal Aviation Administration

    Definitions of miles-in-trail, ground delay programs and ground stops.

  3. National Airspace System Status · FAA Air Traffic Control System Command Center

    Live list of active ground delay programs and ground stops at U.S. airports.

  4. Network Manager · EUROCONTROL

    How Europe's air traffic flow and capacity management allocates departure slots when sectors are constrained.

  5. Delays and cancellations · UK Civil Aviation Authority

    Passenger rights under UK261, including extraordinary circumstances.

Numbers in the video are the planner's built-in rules for its Scottish outage scenario; flight counts are randomised on every load, and the tool's running delay average is not narrated because it grows with screen frame rate.

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