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Taxiing

Introduction:

  • Taxiing refers to the movement of an aircraft while on the ground, under its down power
  • Once your engine has started you must be aware of what you're doing and keep a visual scan, your "flight" has begun
    • It may be required initially to tow the aircraft before engines are started to be safe

Taxiing:

  • Approval must be obtained prior to moving an aircraft or vehicle onto the movement area during the hours an Air Traffic Control Tower (ATCT) is in operation
    • Always state your position on the airport when calling the tower for taxi instructions
    • The movement area is normally described in local bulletins issued by the airport manager
      • These bulletins may be found in FSSs, fixed base operators offices, air carrier offices, and operations offices
    • The control tower also issues bulletins describing areas where they cannot provide service due to non-visibility or other reasons
      • This is usually done through ATIS/AWOS remarks

Clearances:

  1. A clearance must be obtained prior to taxiing on a runway, taking off, or landing during the hours an Airport Traffic Control Tower is in operation
  2. A clearance must be obtained prior to crossing any runway. ATC will issue an explicit clearance for all runway crossings
  3. When assigned a takeoff runway, ATC will first specify the runway, issue taxi instructions, and state any hold short instructions or runway crossing clearances if the taxi route will cross a runway. This does not authorize the aircraft to "enter" or "cross" the assigned departure runway at any point. In order to preclude misunderstandings in radio communications, ATC will not use the word "cleared" in conjunction with authorization for aircraft to taxi
  4. When issuing taxi instructions to any point other than an assigned takeoff runway, ATC will specify the point to taxi to, issue taxi instructions, and state any hold short instructions or runway crossing clearances if the taxi route will cross a runway. NOTE: ATC is required to obtain a read-back from the pilot of all runway hold short instructions
  5. If a pilot is expected to hold short of a runway approach ("APPCH") area or ILS holding position (see FIG 2−3−15, Taxiways Located in Runway Approach Area), ATC will issue instructions
  6. When taxi instructions are received from the controller, pilots should always read back:
    • The runway assignment
    • Any clearance to enter a specific runway
    • Any instruction to hold short of a specific runway or line up and wait

    • Controllers are required to request a read-back of runway hold short assignment when it is not received from the pilot/vehicle
  7. ATC clearances or instructions pertaining to taxiing are predicated on known traffic and known physical airport conditions. Therefore, it is important that pilots clearly understand the clearance or instruction. Although an ATC clearance is issued for taxiing purposes, when operating in accordance with the CFRs, it is the responsibility of the pilot to avoid collision with other aircraft. Since "the pilot−in−command of an aircraft is directly responsible for, and is the final authority as to, the operation of that aircraft" the pilot should obtain clarification of any clearance or instruction which is not understood

Operating Practices:

  1. Good operating practice dictates that pilots acknowledge all runway crossing, hold short, or takeoff clearances unless there is some misunderstanding, at which time the pilot should query the controller until the clearance is understood
    • NOTE: Air traffic controllers are required to obtain from the pilot a read-back of all runway hold short instructions
  2. Pilots operating a single pilot aircraft should monitor only assigned ATC communications after being cleared onto the active runway for departure. Single pilot aircraft should not monitor other than ATC communications until flight from Class B, Class C, or Class D surface area is completed. This same procedure should be practiced from after receipt of the clearance for landing until the landing and taxi activities are complete. Proper effective scanning for other aircraft, surface vehicles, or other objects should be continuously exercised in all cases
  3. If the pilot is unfamiliar with the airport or for any reason confusion exists as to the correct taxi routing, a request may be made for progressive taxi instructions which include step−by−step routing directions. Progressive instructions may also be issued if the controller deems it necessary due to traffic or field conditions (for example, construction or closed taxiways)
  • At those airports where the U.S. Government operates the control tower and ATC has authorized noncompliance with the requirement for two−way radio communications while operating within the Class B, Class C, or Class D surface area, or at those airports where the U.S. Government does not operate the control tower and radio communications cannot be established, pilots must obtain a clearance by visual light signal prior to taxiing on a runway and prior to takeoff and landing

Phraseology:

  • The following phraseologies and procedures are used in radiotelephone communications with aeronautical ground stations
    1. Request for taxi instructions prior to departure:

      • State your aircraft identification, location, type of operation planned (VFR or IFR), and the point of first intended landing
        • Aircraft: "Washington ground, Beechcraft One Three One Five Niner at hangar eight, ready to taxi, I−F−R to Chicago"
        • Tower: "Beechcraft one three one five niner, Washington ground, runway two seven, taxi via taxiways Charlie and Delta, hold short of runway three three left"
        • Aircraft: "Beechcraft One Three One Five Niner, hold short of runway three three left"
    2. Receipt of ATC clearance:

      • ARTCC clearances are relayed to pilots by airport traffic controllers in the following manner
        • Tower: "Beechcraft One Three One Five Niner, cleared to the Chicago Midway Airport via Victor Eight, maintain eight thousand"
        • Aircraft: "Beechcraft One Three One Five Niner, cleared to the Chicago Midway Airport via Victor Eight, maintain eight thousand"
    3. NOTE: Normally, an ATC IFR clearance is relayed to a pilot by the ground controller. At busy locations, however, pilots may be instructed by the ground controller to “contact clearance delivery” on a frequency designated for this purpose. No surveillance or control over the movement of traffic is exercised by this position of operation
    4. Request for taxi instructions after landing:

      • State your aircraft identification, location, and that you request taxi instructions
        • Aircraft: “Dulles ground, Beechcraft One Four Two Six One clearing runway one right on taxiway echo three, request clearance to Page”
        • Tower: “Beechcraft One Four Two Six One, Dulles ground, taxi to Page via taxiways echo three, echo one, and echo niner”
    5. or
      • Aircraft: “Orlando ground, Beechcraft One Four Two Six One clearing runway one eight left at taxiway bravo three, request clearance to Page”
      • Tower: “Beechcraft One Four Two Six One, Orlando ground, hold short of runway one eight right”
      • Aircraft: “Beechcraft One Four Two Six One, hold short of runway one eight right”

Taxi During Low Visibility:

  • Pilots and aircraft operators should be constantly aware that during certain low visibility conditions the movement of aircraft and vehicles on airports may not be visible to the tower controller. This may prevent visual confirmation of an aircraft’s adherence to taxi instructions
  • Of vital importance is the need for pilots to notify the controller when difficulties are encountered or at the first indication of becoming disoriented. Pilots should proceed with extreme caution when taxiing toward the sun. When vision difficulties are encountered pilots should immediately inform the controller
  • Advisory Circular 120−57, Low Visibility Operations Surface Movement Guidance and Control System, commonly known as LVOSMGCS (pronounced “LVO SMIGS”) describes an adequate example of a low visibility taxi plan for any airport which has takeoff or landing operations in less than 1,200 feet runway visual range (RVR) visibility conditions. These plans, which affect aircrew and vehicle operators, may incorporate additional lighting, markings, and procedures to control airport surface traffic. They will be addressed at two levels; operations less than 1,200 feet RVR to 500 feet RVR and operations less than 500 feet RVR
    • Specific lighting systems and surface markings may be found in Paragraph 2−1−11, Taxiway Lights, and Paragraph 2−3−4, Taxiway Markings
  • When low visibility conditions exist, pilots should focus their entire attention on the safe operation of the aircraft while it is moving. Checklists and nonessential communication should be withheld until the aircraft is stopped and the brakes set

Regulation:

  • Taxi/landing lights shall be utilized to the maximum extent possible at night except to avoid blinding another pilot
    • The use of takeoffs-and-landings/taxi lights is an effective means of illuminating surface hazards during taxi movements at night and alerting all concerned of an aircraft's presence/position in flight
  • FAR 91.209 has specific guidance as to lighting requirements

Airplane Flying Handbook, Crosswind Taxiing Technique
Figure 1: Airplane Flying Handbook, Crosswind Taxiing Technique

Taxi Speed:

  • Taxi speed is not specifically regulated; however, common sense must apply so as not to operate in a careless or reckless manner (FAR 91.13)
    • You should never taxi any faster than a man can walk in the line
    • While on a taxiway, you should not taxi faster than a man could jog
    • When entering a turn, be mindful of the stress you are placing on the gear as you turn and slow down
    • Care must be exercised when taxiing at night, in low visibility, or toward the sun to remain situational awareness as to where you are
      • This means half the speed and twice the caution

ATC:

  • "Taxi to" means you are cleared to cross all taxiways and runways excepting the assigned takeoff runway
  • "Hold short:" do not cross said runway or taxiway until cleared
  • Progressive Taxi: if a pilot is unfamiliar or the controller feels it necessary, a progressive (guided) taxi will be issued
  • ATC is required to issue "hold shorts" or "cleared to cross" on any runway active or not in between you and your destination
    • ATC will not use the word "cleared" so as not to cause confusion
    • ATC SHOULD make crossing all runways clear
  • ATC will first specify the runway, issue taxi instructions, and then state any required hold short instructions
  • If the pilot is expected to hold short of any runway approach ("APPCH") area or ILS holding position, ATC will issue instructions
  • When taxi instructions are received from the controller, pilots should always read back
    • Runway Assignment
    • Any clearance to enter a specific runway
    • Any instruction to hold short of a specific runway
  • If you fail to supply any of the above information, ATC is required to query you

IT IS THE PILOT'S RESPONSIBILITY TO SEE AND AVOID ON THE TAXIWAY AS WELL

Airplane Flying Handbook, Downwind Taxi
Figure 2: Airplane Flying Handbook,
Downwind Taxi

Technique:

  • It will require a large amount of power to initially move the aircraft
    • As the aircraft starts to move, power must be retarded, possibly as far back as idle, to prevent continued acceleration
  • Steer with rudders, keeping your feet over, but not on, the breaks
  • Riding the brakes will reduce their lifespan and could render them less effective
    • Many high performance aircraft can produce enough thrust that riding the brakes may be necessary to keep the aircraft from speeding up; brake judiciously
    Airplane Flying Handbook, Quartering Tailwind
    Figure 2: Airplane Flying Handbook,
    Quartering Tailwind
  • Jet aircraft can be dangerous when exhaust is swept across an area
  • Reduce the power to idle in a turn, but remember an aircraft stopped in a turn takes a lot of power to get moving again
    • Always execute good "tail pipe courtesy"

Wind:

  • Move the control surfaces in accordance with the wind
    • Every turn you make, you should change the control positions
  • Moderate to strong headwinds and/or a strong propeller slipstream makes the use of the elevator sometimes necessary to control pitch
  • Airplane Flying Handbook, Quartering Headwind
    Figure 3: Airplane Flying Handbook,
    Quartering Headwind
  • Downwind taxiing will usually require less power and may require none, but do not ride the brakes
  • The upwind wing will tend to be lifted by the wind unless the aileron control is held in that direction
  • Weathervaning may occur as the wind effects a large portion of the aircrafts side [Figure 4]
    • This is more apparent in a tail wheel aircraft

Communications:

  • Always state your position when calling for taxi
    • ATC: "[Agency] Ground, [Callsign], taxi from [Location] with [Information]"
  • Upon reaching an intersection, you should get in the habit and tell yourself or say allowed if with others
    • ATC: "Cleared left, forward and right, going [Left/Forward/Right]"
  • A low visibility taxi plan will exist giving the pilot additional instructions when the RVR is less than 1,200' and again in operations less than 600' RVR
  • Do not switch frequencies while taxiing, in case ground needs to contact you
  • Auto-switch tower when approaching the hold short to monitor traffic
  • If you have just cleared a runway and are looking to taxi, call with intentions as appropriate
    • ATC: "[Agency] Ground, [Callsign], clear of [Runway] at [Location], taxi to [Location]"

Airplane Flying Handbook, Surface Area Most Affected By Wind
Figure 4: Airplane Flying Handbook,
Surface Area Most Affected By Wind

Exiting the Runway:

  • Exit without delay at the first available taxiway or as instructed
  • All parts of the aircraft must be across the hold short line to be considered off the runway
  • Contact ground when directed by tower

Dangers:

  • Personnel must always be aware of the dangers associated with moving surfaces
  • Rotor wash created by the blades of a rotary-winged aircraft or thrust from the exhaust section of a fixed-winged aircraft may cause severe personnel injury
  • The proper safety equipment must always be worn when working on flight decks and flight lines

Hand Signals:


Case Studies:

  • NTSB Identification: MIA01LA034 The National Transportation Safety Board determines the probable cause(s) of this accident to be: The student pilot's failure to maintain a visual look out while transitioning from the active runway to a taxiway resulting in an on-ground collision with a taxiway sign

Conclusion:


References: