Unlike fixed-wing aircraft, helicopters can use different taxi techniques: wheeled helicopter taxi, hovertaxi, and air-taxi. The way a helicopter may proceed on ground greatly depends on whether it has a skid or a wheel assembly. Wheeled helicopters can taxi like any fixed wing aircraft, without lifting off the ground. Helicopters with skid assembly have to become airborne prior to taxiing. When determining the preferred taxi method for a particular helicopter, refer to the guidelines below, or try to accommodate a pilot's specific request if one is made.
a. When necessary for a wheeled helicopter to taxi on the surface, use the phraseology in Topic 3, Taxi and Ground Movement Procedures.
EXAMPLE-
“Runway 16L, taxi via Bravo, Charlie.”
NOTE-
Ground taxiing uses less fuel than hover-taxiing and minimizes air turbulence. However, under certain conditions, such as rough, soft, or uneven terrain, it may become necessary to hover/air-taxi for safety considerations. Helicopters with articulating rotors (usually designs with three or more main rotor blades) are subject to “ground resonance” and may, on rare occasions, suddenly lift off the ground to avoid severe damage or destruction.
b. When requested or necessary for a helicopter/VTOL aircraft to proceed at a slow speed above the surface, normally below 20 knots and in ground effect, use the following phraseology, supplemented as appropriate with the phraseology in Topic 3, Taxi and Ground Movement Procedures.
PHRASEOLOGY-
HOVERTAXI (supplemented, as appropriate, from Topic 3, Taxi and Ground Movement Procedures.)
CAUTION (dust, blowing snow, loose debris, taxiing light aircraft, etc.).
EXAMPLE-
“Runway 16L, hover-taxi via Bravo, Charlie.”
NOTE-
Hovertaxiing consumes fuel at a high burn rate, and helicopter downwash turbulence (produced in ground effect) increases significantly with larger and heavier helicopters.
c. When requested or necessary for a helicopter to proceed expeditiously from one point to another, normally below 100 feet AGL and at airspeeds above 20 knots, use the following phraseology, supplemented as appropriate with the phraseology in Topic 3, Taxi and Ground Movement Procedures.
PHRASEOLOGY-
AIRTAXI:
VIA (direct, as requested, or specified route)
TO (location, heliport, helipad, operating/movement area, active/inactive runway).
AVOID (aircraft).
If required,
REMAIN AT OR BELOW (altitude).
CAUTION (wake turbulence or other reasons above).
LAND AND CONTACT TOWER,
or
HOLD FOR (reason- takeoff clearance, release, landing/taxiing aircraft, etc.).
EXAMPLE-
“Air-taxi direct to runway 16L, avoid Cherokee northbound on Bravo.”
“Air-taxi as requested to runway 16L, land and contact tower 119.3”
NOTE-
Airtaxi is the preferred method for helicopter movements on airports provided ground operations/conditions permit. Air-taxi authorizes the pilot to proceed above the surface either via hover-taxi or flight at speeds more than 20 knots. Unless otherwise requested or instructed, the pilot is expected to remain below 100 feet AGL. The pilot is solely responsible for selecting a safe airspeed for the altitude/operation being conducted.
d. The rotorwash effect produced by a taxiing or hover-taxiing helicopter may adversely affect other aircraft. For this reason, avoid clearances which require small aircraft or helicopters to taxi in close proximity to taxiing or hover-taxi helicopters.