Tower (TWR)

The role of TWR

The tower clears the helicopter to land and take off, on the runway or away from it, controls the traffic circuit and clears crossings of the control zone. With helicopters it has more freedom than with aeroplanes: it can send them to different landing points, fit them between aeroplanes and make them wait stationary in the air. In return, it has to watch the rotor downwash and where the light aeroplanes are.

The premises

1. The runway is an option, not a requirement. The tower may clear a helicopter to land or take off on the runway, at the pilot's request. After consulting the pilot, it may also clear landings and take-offs on helipads, taxiways or stands (items 5.1.3.1 and 5.1.3.2 of the ICA 100-4)¹.
2. Keep away from the aeroplanes. As far as possible, helicopter paths should avoid other aircraft (item 5.1.3.1, Note)¹. It does not need to fly the runway final to land on the apron.
3. Mind the light aircraft. A helicopter hovering or air-taxiing is kept clear of LIGHT aircraft (Art. 207 of the ICA 100-37)².
4. What the tower cannot see, the pilot decides. If the landing or take-off point is outside the manoeuvring area, out of the tower's sight or off the aerodrome, the tower uses the phraseology in chapter 7 of the ICA 100-4 (item 5.1.1)¹. It does not "clear" a landing at a place it cannot see: it says the landing is at the pilot's own risk.
5. Priorities apply to helicopters too. Air ambulance, SAR and public safety flights have priority for take-off and landing (Arts. 601 and 608 of the ICA 100-37)². See Special Operations.

The tasks

Take-off

A helicopter may take off from the runway, a taxiway, a helipad or its present position. The clearance says from where: "cleared for take-off from present position" (or from taxiway C, or from runway 35L) (item 7.2.3)¹.

Before clearing it, check:

• whether the departure path crosses the final or the take-off path of any runway in use. If it does, the take-off waits, or the departure goes the other way;
• whether a light aircraft is close enough to get the downwash;
• by which REH or gate the helicopter will leave, if any.

Landing

A helicopter arrival has three cases:

A helicopter coming along an REH normally goes straight to its landing point, without joining the aeroplane circuit. The ICA 100-4 asks that, where helicopters are part of the daily traffic, the unit set up dedicated paths, with direct approaches and departures on headings that suit the route (item 5.3)¹.

Separation between helicopters

Away from the runway, a helicopter is cleared to land or take off only when the one ahead, taking off or landing, has left the landing and take-off area (item 5.1.4)¹.

Two helicopters may land or take off at the same time if (item 5.1.5)¹:

• their paths do not conflict;
• the landing or take-off points are at least 60 m apart laterally; and
• both are instructed to stay at least 60 m from each other.

Between helicopters and aeroplanes using the runway, the runway separation rules and the ICA 100-37 wake turbulence minima apply (Art. 544)². A small helicopter is a LIGHT aircraft: behind a MEDIUM or HEAVY aeroplane, it needs the same wake time as any light aircraft.

Traffic circuit

The ICA 100-37 sets no circuit height for helicopters (Art. 678 covers aeroplanes)². At an aerodrome without a tower, the ICA 100-4 has helicopters fly the circuit at 500 ft, without crossing the runways' final approach paths (item 5.2)¹. At a controlled aerodrome, the VAC or the tower's instructions apply.

Crossing the CTR or the aerodrome

A transiting helicopter asks to cross the control zone, often along an REH. The tower clears the crossing with an altitude and an exit point, and does not let it cross the extended centreline of the runway in use without a clearance. Where an REH is published, the helicopter should stay on it at the published altitudes (item 5.4.2)¹.

Special VFR

With the weather below the helicopter's VFR minima, it can only operate as special VFR, by day and inside the CTR or ATZ. The tower passes on a special VFR clearance only after getting it from APP (Art. 847 of the ICA 100-37), and special VFR flights are separated from IFR flights and from each other (Art. 39)². See the note in Fundamentals.

Making it wait

A helicopter can wait stationary. It is the tower's most useful tool with helicopters: instead of sending it round in circles, have it hold over a known point, clear of the aeroplane paths, until the runway is clear for the crossing.

Frequency changes

As on the ground, avoid changing the frequency of a single-pilot helicopter while it hovers. Relay the next unit's instructions until it can change (item 5.1.2.5)¹.

On the network

The tower is an S2 position under the GCAP, with a maximum range of 50 NM³. With GND offline, the tower covers the ground under the top-down principle (GCAP 4.6)³: it also clears ground taxi, air-taxi and air-transit.

The CoC forbids connecting on a runway or taxiway (item B1)⁴, but says nothing about helipads. A helicopter that appears on a helipad inside the aerodrome has connected properly.