Fundamentals
What a helicopter does differently
Four helicopter capabilities change the controller's work:
| Capability | What it means for control |
|---|---|
| Stopping in the air (hovering) | The helicopter can wait stationary over a point. It needs no orbit or circuit to hold |
| Vertical take-off and landing | It needs no runway. It can depart from an apron, a taxiway or a helipad |
| Flying slow and low | It fits between aeroplanes, but takes time to get out of the way and makes a lot of turbulence near the ground |
| Following ground references | It flies narrow visual corridors (the REH), away from aeroplane paths |
None of these capabilities removes the need for control. At a controlled aerodrome, a helicopter needs a clearance to move, take off and land, like any aircraft.
The vocabulary
The definitions below are from the ICA 100-41 and DECEA's glossary, the MCA 100-273. They are worth learning, because the phraseology uses exactly these words.
| Term | Simplified definition | Speed and height |
|---|---|---|
| Ground taxi | A wheeled helicopter rolls along the taxiways, like an aeroplane | On the ground |
| Air-taxi | Movement above the surface, hovering low, in ground effect | Below 20 kt, normally at ground-effect height. Some helicopters need to air-taxi above 25 ft |
| Air-transit | Faster movement over the aerodrome, along an air-transit route | Above 20 kt and below 100 ft |
| Air-transit route | A defined path on the aerodrome for helicopter air-transit | Up to 100 ft |
| Helipad (heliport) | An aerodrome used exclusively by helicopters | — |
| Occasional landing area | An area chosen and marked for sporadic use, in police, civil defence, medical, power line or pipeline inspection operations etc. | VMC only |
| Helicopter stand | Where a helicopter may air-taxi, touch down and lift off | — |
| Ground effect | Extra lift near the surface, up to about one rotor diameter in height | — |
| REH | Helicopter Special Route: a published visual corridor to organise helicopters inside a CTR or TMA, exclusively for VFR helicopter flights, with as much open ground as possible for an emergency landing | Published maximum altitudes by direction of flight, to keep clear of IFR traffic |
Under the ICA 100-4, "aerodrome" does not include helipads, non-certified sites or occasional landing areas1. When the manual speaks of a "landing away from the aerodrome", that is what it means.
Taxi, air-taxi or air-transit?
Ground taxi burns less fuel and raises less dust, and should be preferred for wheeled helicopters. Air-taxi burns a lot of fuel and blows hard. Air-transit is the fastest, but only exists where there is an air-transit route. A skid-equipped helicopter cannot roll: it either air-taxis or does not move1. In the glossary, a helicopter's "taxi" also covers movement at low height (entry 735)3; in phraseology, however, use the three separate words, as the ICA 100-4 requires.
Rotor downwash and wake
When hovering or air-taxiing, the rotor drives air downwards at high speed over a distance of about three rotor diameters. Per kilogram, a helicopter's vortices are stronger than those of a fixed-wing aircraft. That is why the ICA 100-37 requires helicopters hovering or air-taxiing to be kept clear of LIGHT aircraft (Art. 207)2, and the ICA 100-4 repeats the rule (item 2.2.1)1.
The controller must also consider "rotor downwash" on aircraft taxiing, taking off or landing, and on vehicles and people, when issuing clearances (Art. 545 of the ICA 100-37)2.
In practice:
- do not air-taxi a helicopter next to a parked or taxiing single-engine aircraft;
- do not let a helicopter hover near the threshold where a light aircraft is landing;
- prefer ground taxi when the helicopter has wheels and there are light aircraft nearby.
Helicopter VFR rules
Helicopters have their own VFR minima, lower than an aeroplane's. That is what lets them fly when the aerodrome is already closed to VFR aeroplanes. The ICA 100-12 itself points to them: "flight visibility and distance from cloud minima for helicopters are given in the ICA 100-4" (Art. 104, § 5)5. The values are from the ICA 100-41:
| Situation | Visibility | Distance from cloud |
|---|---|---|
| Controlled airspace, or uncontrolled above 3,000 ft altitude or 1,000 ft height | 3,000 m | 1,500 m horizontally and 500 ft vertically |
| Uncontrolled, below 3,000 ft altitude or 1,000 ft height | 1,000 m, if the speed allows seeing and avoiding traffic | Clear of cloud, in sight of ground or water |
| Take-off and landing at the aerodrome or helipad | 1,500 m, with a 600 ft ceiling | — |
Where there is a visual approach chart (VAC), its minima apply (item 3.3.2)1.
For comparison: the general ICA 100-12 rule requires 5 km flight visibility and, to land, take off or join the circuit VFR, a 1,500 ft ceiling and 5 km visibility (Arts. 104 and 109)5.
Minimum heights: over cities, towns and groups of people, 500 ft above the highest obstacle within 600 m. Elsewhere, a height that allows a safe emergency landing, at least 200 ft. Take-off and landing are exempt from these heights (item 3.2)1. The general ICA 100-12 rule, for aeroplanes, is higher: 1,000 ft over built-up areas and 500 ft elsewhere (Art. 110)5.
At night, helicopters do not land at non-certified sites or occasional landing areas (item 3.4.3.1)1. Night VFR requires an IFR-rated pilot and IFR-certified aircraft, except for flights entirely inside an ATZ, CTR or TMA, or within 27 NM of the departure aerodrome (item 3.4.3.2 of the ICA 100-4 and Arts. 120 to 122 of the ICA 100-12)15. The exception is special public aviation operations, such as police flights, which RBAC 90 allows at night at unregistered sites, under conditions (section 90.303)4. On the network these operations are restricted: see Special Operations.
Special VFR
Below VFR minima, a flight can only continue as special VFR: by day only, only inside the CTR or ATZ of a controlled aerodrome and always with a clearance (Arts. 132 and 133 of the ICA 100-12)5. The minima for clearing it are a 1,000 ft ceiling and 3,000 m visibility, assessed case by case (Art. 134 of the ICA 100-12 and Art. 489 of the ICA 100-37)52. With visibility below 1,500 m, a helicopter on special VFR flies below 140 kt (Art. 131)5. Special VFR flights are separated by ATC and are not vectored (Arts. 39 and 1025 of the ICA 100-37)2.
IFR helicopters
On an IFR approach, the helicopter flies as category A, unless the procedure is for helicopters only (HEL ONLY). On a category A procedure, it gets a 50% reduction in minimum visibility (item 4.2)1. For APP, it is a slow IFR flight: sequence it like a single-engine aircraft. There are also PinS (Point in Space) IFR procedures, for helicopters only, which lead to a point in space from which the pilot continues visually to the helipad.
Who decides what
Away from designated areas (runway, helipad, stand), a helicopter may land and take off elsewhere, but obstacle clearance becomes the pilot's responsibility (item 2.4)1. At a non-certified site, the operation is occasional and "under the full responsibility of the operator and/or pilot", and the ATS unit assumes the ANAC conditions have been met (item 2.4.5)1.
That gives the controller a simple rule: the controller looks after the traffic, the pilot looks after the landing site. You do not need to know whether that apron can take the helicopter. You need to know whether it will cross someone's final.
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ICA 100-4, Special Air Traffic Rules and Procedures for Helicopters: item 1.3 (definitions), chapter 2 (general rules), chapter 3 (VFR) and chapter 4 (IFR). Portaria DECEA nº 109/DGCEA, of 21/07/2021. ↩↩↩↩↩↩↩↩↩↩↩↩
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ICA 100-37, Air Traffic Services: Art. 207 (helicopter wake), Art. 489 (special VFR) and Art. 545 (jet blast and rotor downwash). Edition with the 2nd amendment (Portaria DECEA/DNOR1 nº 2.197, of 18/08/2026), in force on 26/11/2026. ↩↩↩↩
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MCA 100-27, ATM Glossary: Annex III, entries 238 (air-transit), 626 (air-transit route), 628 (REH), 735 (taxi) and 737 (air-taxi). Portaria DECEA/DNOR1 nº 2.218, of 25/08/2026, in force on 26/11/2026. ↩↩
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RBAC 90, Requirements for Special Public Aviation Operations, amendment 04 (ANAC Resolution nº 805, of 2026): section 90.303. ↩
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ICA 100-12, Rules of the Air: Arts. 104 (§ 5), 109, 110, 120 to 122 and 131 to 134. Edition with the 1st amendment (Portaria DECEA/DNOR1 nº 2.168, of 09/07/2026), in force on 26/11/2026. ↩↩↩↩↩↩↩