London helicopter routes and control zones

Helicopters crossing central London follow predetermined routes inside the London and London City control zones (CTRs). The routes carry numbers such as H3, H4, H9 and H10, and every flight in these zones needs a clearance from air traffic control. Controllers often give more direct routings than the printed routes.

The official chart

What the chart shows

• Routes. H2, H3, H4, H5, H7, H9 and H10 appear on the chart; each is a line between reporting points.
• Reporting points. Compulsory and on-request points are marked, with a symbol where holding may be needed, plus visual reference points such as bridges, stadiums and motorway junctions.
• Single-engine helicopters. The chart notes that flights by single-engined helicopters in the inner area are normally prohibited except along the River Thames.
• Heathrow local flying area. See the Heathrow AD 2.22 entry in the AIP.
• Transponder. The London CTR is a Mode S transponder mandatory zone.

How clearance works

All helicopter flights in the London and London City CTRs need ATC clearance

Because of the airspace classification every helicopter flight inside the London (Heathrow) CTR and London City CTR is subject to an ATC clearance. Pilots navigate visually with limited ATC help and stay responsible for the Rules of the Air.
Reference: CAA London helicopter operations page; UK AIP EGLL AD 2.22 para 10 caa.co.uk

VFR/SVFR clearance from Heathrow Radar

All VFR and Special VFR helicopter flying in the London CTR needs ATC clearance (exceptions: Local Flying Areas of Brooklands, Denham, Fairoaks, White Waltham). Clearance is obtained from Heathrow Radar on 125.625 MHz; pilots should call at least 3 minutes before the CTR boundary giving callsign, type, route, ETA, entry point and destination.
Reference: UK AIP EGLL AD 2.22 para 10 (AIRAC 11/2026). AIP wording: 'Pilots must obtain a VFR or Special VFR clearance from Heathrow Radar.' aurora.nats.co.uk

Routes are predetermined but ATC often gives direct routings

Predetermined routes exist across the CTRs but ATC often clears twin-engine helicopters on more direct routings. Accepting a clearance does not relieve the pilot of Rules of the Air responsibilities. NPAS and HEMS multi-engine helicopters have special requirements, may fly lower, hold over locations, or be exempt from some rules.
Reference: CAA London helicopter operations page caa.co.uk

Transponder: London CTR is a Mode S TMZ

The London CTR is notified as a Mode S Elementary Transponder Mandatory Zone with the same lateral and vertical limits as the CTR. Exceptions are in GEN 1.5 para 5.3.4, the AD 2 entries for EGLD, EGTF, EGLM, and for Brooklands (AD 2.22 para 9).
Reference: UK AIP EGLL AD 2.22.14 aurora.nats.co.uk

Holding on routes

Helicopters may be held at published holding points. H4 has no holding between Vauxhall and Westminster Bridges except Flight Priority A or B; no holding points east of London Heliport (nearest Greenwich Marshes). H9: hold at Bedfont in daylight if vis 5 km and ceiling 1,500 ft, otherwise at Feltham.
Reference: UK AIP EGLL AD 2.22 para 10 and route table notes aurora.nats.co.uk

Recommended minimum altitudes on routes (2025 change)

The London Helicopter Routes Working Group updated the AIP to give recommended minimum altitudes, for example 1,000 ft amsl for the whole of H4 between Barnes and the Isle of Dogs. CAA targeted AIRAC 07/2025 (10 July 2025) per its timeline.
Reference: CAP 3066 para 1.3 (Dec 2024); AIRAC 07/2025 stated as 'expected' caa.co.uk

Keep reading

See how air traffic control handles helicopters, why single-engine helicopters follow the Thames and the 2025 and 2026 changes.