Runway Track Vs Runway Heading

[Pilot_92]

Hello all
When I did my pilot's license, I used to hear the term from ATC " Maintain Runway Heading" before takeoff. Nowadays as a first officer flying jet, I hear either " maintain runway heading" and sometimes I hear " maintain runway track". I know that runway track corrects for wind and heading does not. However, I have two questions that I would love to have answers for:
1- Why would we fly runway heading if there is a high chance to be off heading and runway track would alway be accurate?
2- Why during pilot's licenses ( which I did in the U.S), I never heard the term " maintain runway track"? Is it because the U.S ATC doesn't use the term Maintain Runway Track?
Please if you know the answer let me know.

Thank you all

[max alt]

Originally Posted by Pilot_92

Hello all
When I did my pilot's license, I used to hear the term from ATC " Maintain Runway Heading" before takeoff. Nowadays as a first officer flying jet, I hear either " maintain runway heading" and sometimes I hear " maintain runway track". I know that runway track corrects for wind and heading does not. However, I have two questions that I would love to have answers for:
1- Why would we fly runway heading if there is a high chance to be off heading and runway track would alway be accurate?
2- Why during pilot's licenses ( which I did in the U.S), I never heard the term " maintain runway track"? Is it because the U.S ATC doesn't use the term Maintain Runway Track?
Please if you know the answer let me know.

Thank you all

Maintain runway heading allows for departure with drift,maintain runway track means allow for drift to Maintain the Track,as I recall.
Cheers,
M

[Whopity]

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.

The Runway of course does not have a heading, its not going anywhere.

Runway Track implies that you maintain the extended centreline.

[eckhard]

In the days before GPS, IRS and a good indication of current track, it was felt safer for everyone to follow the runway heading without allowing for drift. That way, if two aircraft departed from parallel runways, they would follow parallel tracks as they would both be flying the same heading and being affected by the same wind.

If they were asked to follow the runway track, both pilots might make different drift allowances, resulting in possible converging tracks.

[Fl1ingfrog]

It is true that the many FAA and independant U.S. publications state that an instruction to fly the runway heading means to steer the actual published magnetic measurement and the pilot should not to allow for drift. I've always considered this as odd. Aircraft climb at different speeds and therefore will experience different rates of drift. First, the climb path is designed to give maximum separation from obstacles and not only from other aircraft taking off on a parallel runway.. CFIT forms a large part in the accident statistics. An aircraft climbing at 80 kts with an average cross wind of 20 kts will drift 15 degrees. Another aircraft climbing at 120 kts will drift 10 degrees, so a convergence factor of 5 degrees. At a stronger crosswind of 30 kts the convergence increases to an alarming 22 degrees and 15 degrees respectively, so a convergence of 7 degrees.

Within the UK such instructions are not used by ATC.

CAP 413 edition 23 published 9th April 2020

4.37

An Omnidirectional Departure procedure is designed on the basis that an aircraft maintains runway direction until it reaches such a height that it can make a turn in any direction and maintain the prescribed obstacle clearance.

“BIGJET 347 Omnidirectional Departure runway 27 on track REVTU climb Flight Level 80”

4.38

Local departure instructions may be given prior to the take-off clearance. Such instructions are normally given to ensure separation between aircraft operating in the vicinity of the aerodrome.

“BIGJET 347, after departure track extended centre line.”

“BIGJET 347, after departure climb straight ahead.”

[Whopity]

Within the UK such instructions are not used by ATC.

It was used quite extensively by RAF ATC because I always wondered what they really intended a pilot to do. I don't recall reading any document that gave an explanation other than an FAA document. I also remember being asked by an RAF ATCO when joining a hold to "keep it tight" to which I responded due you want me to change the timing from 1 minute, the response "no, just keep it tight" displayed a total lack of understanding of a hold.

[BEagle]

I always thought that there were only 2 options:

1. "Maintain runway heading" meant that you didn't apply drift on departure.

2. "Straight ahead" mean that you tracked the extended centreline, hence applied drift.