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.
Some existing procedures specify, “Climb runway heading.” Over time, …these departure instructions will be updated to read, “Climb heading 112 degrees….”
Instrument Procedures Handbook
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.
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