As I mentioned last time, even though we use these modes on just about every flight, it’s important to understand that there’s a big difference between having a basic familiarity with them and knowing exactly what they do.
Don’t stress though, we’ve struggled through the books so you don’t have to.
Read on and whatever you do, please enjoy!
The RUNWAY mode, along with the SRS, is a part of the A320’s TAKEOFF Common Mode.
Remember, common modes incorporate guidance on both the vertical and lateral axes.
In the case of the TAKEOFF mode, the SRS will engage simultaneously with the RUNWAY mode.
Keep in mind that they may be disengaged separately.
The important thing to understand here is that the RUNWAY mode guides the aircraft laterally during takeoff and it has two sub-modes that accomplish this in slightly different ways.
Let’s look a bit closer…
The A320 has two different RUNWAY sub-modes.
These are RWY and RWY TRK and this is how they appear on the FMA.
RWY Mode:
- When a LOC signal is available, the RWY mode provides lateral guidance orders to track the runway centreline (using the LOC signal) during the takeoff roll and the initial part of the climb out, up to 30 ft.
- The RWY TRK mode engages at 30 ft RA if NAV mode does not engage. It provides lateral guidance on the track the aircraft was flying when it engaged.
Ready for your next Checkride?
Probably not as ready as you should be.
Certainly not as ready as you could be.
Click here to find out more about the world’s first and finest, complete emergency management system designed especially for the A320.
- The engagement conditions required by the SRS, which are:
- V2 in the MCDU PERF TO page.
- Slats extended.
- The aircraft has been on the ground for at least 30 seconds.
- Plus these,
- The aircraft is receiving a LOC signal and the LOC deviation is less than ½ dot.The aircraft heading is within 20 degrees of the ILS related course.
- The ILS course is identical to the runway heading of the origin airport as selected for the active flight plan if any.
When Does RWY Mode Disengage?
The RWY mode will disengage if:
- The LOC signal is lost below 30 RA or if the aircraft and runway headings differ by more than 20 degrees.
- Another lateral mode is engaged.
RWY uses the LOC signal to guide the aircraft on the runway centreline while the aircraft is on the ground.
On the PFD you’ll see the FD Yaw Bar and the FMA displays RWY.
What Guidance Does RWY TRK Provide?
RWY TRK engages at 30 FT RA, and guides the aircraft on whatever track the aircraft was flying at the moment of mode engagement.
The FD displays the conventional guidance bar and the FMA displays RWY TRK.
So there you have it, Mate.
I hope you enjoyed this quick look at the RWY and RWY TRK.
They’re an important part of understanding just what the aircraft is doing.
Even thought I’m sure many of you probably had some idea of what these modes do, our knowledge is often a bit more vague than it should be.
There may be many of you who’ve never even heard the term “Common Mode,” before and that’s ok.
The important thing is to realise that modes like these (incorporating both veritcal and lateral guidance) exist and that you can learn more about them.
And that’s just what I’m trying to help you do!
Be kind, be smart, fly well.
Until next time…
So that’s our quick look into the RWY and RWY TRK modes.
I hope you found it informative and maybe even a bit enjoyable.
Perhaps you’ve learned this stuff before, but surely, a quick refresh of the finer points can’t hurt!
Be kind, be smart, fly well.
Until next time…
I think when you wrote:
RWY TRK.
Did you mean to head that just RWY?
G’day BusDriver!
My apologies for not getting to your comment over the weekend, but I was absolutely full on with work and then had some personal stuff which needed attending and couldn’t be blown off.
In any case, thanks so much for the great feedback, Mate.
Thanks also for catching my mistake!
I’ve re-edited it and hope it’s bloody well fixed!
Cheers!
Skip
Also, just for clarity, you might try to ensure you use “RUNWAY” mode when addressing both of the 2 submodes, and only use “RWY” when addressing the one specific RWY submode.
G’day BusDriver!
Spot on once again!
You make a great point and one that I had intentionally meant to make, but then in the writing of the piece, I began to focus on how they are seen on the FMA.
I’ve made some new edits and hope this clarified the fact that the RUNWAY mode has two sub-modes, RWY and RWY TRK.
RWY and RWY TRK are what we see on the FMA.
RUNWAY is what we read about in the FCOM!
Thanks again, Mate!
Cheers!
Skip