Runway Intersections and Back Taxiing

Yeager Airport, Charleston, W. Virginia (Charlie West)

Yeager Airport, Charleston, W. Virginia (Charlie West)


 
Quick, what does back taxi mean?

a) The seat you should take when boarding a New York City Yellow Cab.

b) A ground controller’s clearance to taxi against the overall flow of taxiing traffic on the airport.

c) A tower controller’s clearance to taxi on the runway opposite the direction of takeoff.

When cleared for takeoff, where do you begin your takeoff roll? If you say, “At the beginning of the runway,” you may be right. You may also be wrong.

Fly runway heading versus depart straight out. What is the difference between these two tower clearances?

Get the answers to all of these question in this week’s edition of Radar Contact. Plus one more question you’ll have to figure out for yourself. It’s your question of the week. Come spend a few minutes with me and let’s ponder the mysteries of air traffic control.

Show Notes:

  1. You can plan on departing on a runway from a point abeam a specific taxiway intersection when the ground controller includes a taxiway intersection in his runway assignment for your aircraft. For example: Runway 23 at Alpha 1.
  2. You can find out how much runway will be available for takeoff from any intersection by asking the ground or the tower controller.
  3. If your airplane requires more runway length to safely take off than would be available from an intersection, simply tell Ground or Tower that your will need “full length.”
  4. Some airport layouts only permit you to reach the end of a runway by taxiing on the runway itself. The phrase Tower will use that clears you to use the runway as a taxiway opposite the direction of takeoff is: back taxi.
  5. When departing a tower controlled airport, ATC may assign you to fly runway heading after takeoff. You can find a runway’s heading by looking at the airport diagram.
  6.  
    laxRunways

  7. If Tower tells you to depart straight out, that means you should adjust your heading after liftoff to counter the drifting effect of any crosswind. Crab into the wind to track over the ground along the runway’s extended centerline.
  8. If you have finished reading Radio Mastery for VFR Pilots, I sure would appreciate it if you would write a review at either Amazon.com or at BarnesandNoble.com. Your feedback not only helps me, it also helps other pilots make a decision to get a copy of the book.

Questions of the Week

You have just called for your taxi clearance at the Valdosta Regional Airport in Valdosta, Georgia. Your airplane needs a minimum runway length of 4,000 feet for takeoff. (Take a look at the airport diagram.)

valdostaAirport

The airport is using Runway 17 for arrivals and departures. Runway 17 is 8,002 feet long. Runway 22 is also available for departures. The airport’s NOTAMs say the last 2,000 feet of Runway 22 is closed for repaving with 3,598 available for takeoffs and landings.

Valdosta Ground says to you, “Piper 948 Romeo Victor, Valdosta Ground. Runway 17, taxi via Hotel, then right on Alpha.” As you advance the throttle of your aircraft to begin taxiing you glance at the cockpit’s clock. The currently local time is 5:45 am. The sun will not be up for another hour and a half. There is no moon. Once you are under way, the only lights you see are the taxiway lights and the lighted airport signs showing taxiways and runways.

You reach the end of Taxiway A and perform an engine runup. Now you are ready to depart. You make the radio call, “Valdosta Tower, Piper 948 Romeo Victor is ready.” The tower controller replies, “Piper 948 Romeo Victor, fly runway heading, Runway 17, cleared for takeoff.”

Here’s the question, and it is a two-part question:

First, what specific heading does Valdosta Tower expect you to fly after takeoff?

Second, how can this heading prevent you from crashing during takeoff from the Valdosta Regional Airport on this pitch black morning? Hint: The answer has nothing to do with obstacles or traffic off the departure end of the runway.

When you think you know the answers to those questions, go to ATCcommunication.com/answers. That link will take you to a page where you can get the correct answer to both questions, along with a complete explanation.

{ 2 comments… read them below or add one }

Fred January 3, 2013 at 2:20 am

Jeff, another excellent episode. Happy New Year.

With regards to the “fly runway heading” and the “straight out departure” discussion I was always under the impression a “straight out departure” was equivalent to a downwind departure or cross wind departure meaning that you fly the upwind leg of the traffic pattern (which could include the ground track of the runway direction and including any local noise abatement procedures) and then depart the pattern in that general direction on your enroute heading once clear of the pattern without any further need for instructions from ATC (depending on airspace of course).

“Fly runway heading” is an ATC instruction. You must fly that heading until clear of airspace or instructed to do so by ATC.

I had not considered the wind/ground track angle.

Fred

Reply

JeffKanarish January 3, 2013 at 2:07 pm

Hey Fred,

Thank you for your kind words.

I agree with your comment and I don’t see any contradiction with the information I provided in the show. I suppose I could have gone a little deeper into the background of the clearance. When told to depart straight out, you do fly the ground track of the runway’s extended centerline. I didn’t talk about local noise abatement procedures because that is a subject which requires a show segment of its own.

For the benefit of anyone else who might be reading this, let’s clarify the meaning of an upwind leg. The upwind leg of a traffic pattern, according the AIM, is “A flight path parallel to the landing runway in the direction of landing.” The departure leg begins at the runway’s surface and extends from liftoff to 1/2 mile off of the runway’s departure end, and within 300 feet of traffic pattern altitude. So, technically, when beyond 1/2 mile from the departure end and within 300 feet of traffic pattern altitude, you transition from the departure leg to the upwind leg. (AIM Figure 4-3-1, Components of a Traffic Pattern.) Many pilots think of the upwind leg as the mirror opposite of the downwind leg, but an airplane is considered on the upwind leg anywhere in the traffic pattern when the criteria for the upwind leg is met. I know this is splitting hairs, but this jargon was designed by the FAA, so consider the source!

If you take a look at the AIM’s Figure 4-3-2, Traffic Pattern Operations Single Runway, and look at items 4 and 6, you will see item 4 says to continue straight ahead until beyond the departure end of the runway, and then item 6 gives you the option to continue straight out, or exit 45-degrees to the left or right. An ATC clearance to fly a specific heading after takeoff would supercede the guidance in this illustration. If the question remains, is “Straight out departure approved,” an ATC instruction? It certainly is, and Fred,I absolutely agree with you on its meaning.

Thank you for the great comment!

Jeff

Reply

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