L1-L4 Prioritisation — Airspace Hierarchy
Hierarchical Airspace Allocation
Old thinking: "Democratic" — all airspace users are equal. New thinking: Priority levels — fast movers first, drones last.
Priority Levels
L1 — Fast Movers
Aircraft: F-35, Eurofighter, combat jets Priority: Absolute — always priority Speed: 500+ knots Altitude: All levels (including low-level training)
Why L1?
- National security (QRA, air policing)
- Safety (high kinetic energy)
- Training necessity (low-level, high-speed)
L2 — Slow Movers + Test + Military Drones
Aircraft: Helicopters, transport, test platforms, military drones Priority: High — yield to L1 only Speed: Less than 200 knots Altitude: Typically less than 10,000 ft
Includes:
- Military helicopters (SAR, transport)
- Military drones (ISR, strike, logistics)
- Test platforms (new aircraft, prototypes)
- Trainers (C-130, transports)
Within L2 — Drone Priority Sub-levels (managed by Airspace & Littoral Cell):
- L2-A: Strike/ISR drones (combat ops)
- L2-B: Logistics/transport drones (surge ops)
- L2-C: Test/prototype drones (R&D)
L3 — Civil + SAR
Aircraft: Ambulance, police, firefighting, commercial Priority: Medium — yield to L1/L2 Speed: Less than 150 knots Altitude: Less than 5,000 ft (typically)
Use cases:
- Medical (HEMS, ambulance)
- Law enforcement
- Search & Rescue
- Commercial (cargo, inspection)
L4 — Civil Drones
Aircraft: Commercial drones, recreational UAVs, civil test platforms Priority: Low — yield to all (L1, L2, L3) Speed: Less than 100 knots Altitude: Less than 500 ft (typically)
Includes:
- Commercial delivery/inspection drones
- Recreational UAVs
- Civil test platforms (non-military R&D)
Default: Lowest priority, must deconflict with all other traffic.
Note: Military drones are L2, not L4. Civil drones yield to all levels.
Airspace & Littoral Cell — Governance
Role: Manages L2 drone priorities, publishes AUP/UUP, geozone-API, NAVWARN.
L2 Drone Priority Management
Within L2, the Airspace & Littoral Cell manages sub-priorities:
| Sub-level | Type | Priority within L2 | Use case |
|---|---|---|---|
| L2-A | Strike/ISR | Highest within L2 | Combat operations, QRA support |
| L2-B | Logistics/Transport | Medium within L2 | Surge ops, supply chains |
| L2-C | Test/Prototype | Lowest within L2 | R&D, trials, TEVV |
Deconfliction within L2:
- L2-C yields to L2-B, L2-A
- L2-B yields to L2-A
- All L2 yields to L1
Instruments
- AUP/UUP (Airspace Use Plan / Updated UUP) — Daily airspace allocation
- Geozone-API — Real-time geofencing data for UTM
- NAVWARN — Navigational warnings for maritime/littoral
- Dynamic NOTAMs — Temporary restrictions during escalation
KPIs
- Time-to-activate L2-A/L2-B — ≤ 5 min
- Geofence compliance — ≥ 99.5%
- L1/L2 conflicts — 0 (zero tolerance)
See also: Ecosystem Elements → Test & Certification
Operational Rules
Deconfliction
When conflict:
- L4 yields to L3, L2, L1 (always)
- L3 yields to L2, L1
- L2 yields to L1
- L1 has absolute priority
How:
- Altitude separation (drones below 500 ft)
- Geographic separation (restricted areas)
- Temporal separation (time windows)
- Procedural (NOTAM, UTM coordination)
Dynamic Airspace Allocation
Normal conditions:
- L4 (drones) can operate in allocated blocks
- L3 (civil/SAR) coordinates via UTM
- L2 (slow/test) files flight plans
- L1 (fast movers) has priority lanes
During escalation (military exercise, QRA):
- L1 takes precedence → L4 must ground
- L2/L3 coordinate with military ATC
- Dynamic NOTAMs issued
Example: Baltic Scenario
Scenario: Russian bomber approaches Baltic airspace → QRA (Quick Reaction Alert) F-35 scramble.
Response:
| Level | Action | Timeframe |
|---|---|---|
| L1 (F-35 QRA) | Immediate takeoff, priority routing | T+0 min |
| L2 (Heli training) | Hold position, coordinate | T+2 min |
| L3 (HEMS ambulance) | Reroute if in conflict zone | T+5 min |
| L4 (Commercial drones) | Ground all ops in 50 NM radius | T+0 min (auto via UTM) |
Result: L1 gets unimpeded access, others adapt/ground.
Why This Matters
Current "democratic" system:
- Gridlock (everyone waits for everyone)
- Safety issues (drones interfere with fast movers)
- Inefficiency (L1 can't train freely)
L1-L4 system:
- Clear hierarchy (no ambiguity)
- Safety (fast movers never impeded)
- Efficiency (L4 operates when safe, grounds when not)
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