“Fly Runway Heading”

I have noticed continued confusion among IFR pilots about the instruction to “fly runway heading” during an instrument departure. Many pilots, drawing on their primary training, think they should apply appropriate drift correction to maintain the track of the extended runway centerline. But that’s not what the instruction means or what ATC expects.

First, from the Pilot/Controller Glossary, note the definition of Runway Heading:

RUNWAY HEADING− The magnetic direction that corresponds with the runway centerline extended, not the painted runway number. When cleared to “fly or maintain runway heading,” pilots are expected to fly or maintain the heading that corresponds with the extended centerline of the departure runway. Drift correction shall not be applied; e.g., Runway 4, actual magnetic heading of the runway centerline 044, fly 044.

The same guidance is described in the Instrument Procedures Handbook:

Additionally, when required, departure instructions specify the actual heading to be flown after takeoff, as is the case in figure 2-34 under the departure route description, “Climb via heading 112 degrees…” Some existing procedures specify, “Climb runway heading.” Over time, both of these departure instructions will be updated to read, “Climb heading 112 degrees….” Runway Heading is the magnetic direction that corresponds with the runway centerline extended (charted on the AIRPORT DIAGRAM), not the numbers painted on the runway. Pilots cleared to “fly or maintain runway heading” are expected to fly or maintain the published heading that corresponds with the extended centerline of the departure runway (until otherwise instructed by ATC), and are not to apply drift correction; e.g. RWY 11, actual magnetic heading of the runway centerline 112.2 degrees, “fly heading 112 degrees.” In the event of parallel departures this prevents a loss of separation caused by only one aircraft applying a wind drift. (1-42)

Under VFR, however, you should correct drift to remain over the extended centerline of the runway while on the departure leg, unless you are directed to “fly runway heading.” See, for example, the Airplane Flying Handbook (p. 5-6):

The climb with a wind correction angle should be continued to follow a ground track aligned with the runway direction. However, because the force of a crosswind may vary markedly within a few hundred feet of the ground, frequent checks of actual ground track should be made, and the wind correction adjusted as necessary.

The AFH also calls out drift correction in the “common errors” portion of that section:

Inadequate drift correction after lift-off.

The private pilot and commercial pilot ACS also note this requirement. For example, see PA.IV.A.S13 in IV. Takeoffs, Landings, and Go-Arounds of the private pilot ACS:

Maintain directional control and proper wind drift correction throughout takeoff and climb.

Under IFR, the rationale for flying runway heading and not flying a track (when cleared to “fly runway heading” or “fly heading xxx”) is suggested in the Instrument Procedures Handbook section cited earlier, viz.:

…In the event of parallel departures this prevents a loss of separation caused by only one aircraft applying a wind drift.

 

Advertisements

2 Responses to “Fly Runway Heading”

  1. Tom Sheehan says:

    If IFR and assigned runway heading in a 90° crosswind of 29 kts and a climb speed of 55kts you could very easily fly into obstacles as you are drifting at a fast rate.
    Comment?

    • bruceair says:

      Instrument departure procedures are designed with the understanding that an aircraft will climb to 400 ft above the departure end of the runway (DER) before making any turns. This provision allows you to correct for drift immediately after takeoff to avoid close-in obstacles.

      See, for example, p. 1-26 of the Instrument Procedures Handbook and the AIM, both of which note:

      “Unless specified otherwise, required obstacle clearance for all departures, including diverse, is based on the pilot crossing the departure end of the runway at least 35 feet above the departure end of runway elevation, climbing to 400 feet above the departure end of runway elevation before making the initial turn, and maintaining a minimum climb gradient of 200 feet per nautical mile (FPNM), unless required to level off by a crossing restriction, until the minimum IFR altitude.”

      Upon reaching 400 ft AGL, you should fly the headings/courses specified in the clearance or procedure.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: