From the information you’ve provided, it seems to me like an issue with the physics and how they interact with the autopilot. The rocking you are experiencing is likely the autopilot overcorrecting itself which explains why turning off the heading select option for the autopilot stops the rocking. There have been reports in the past of this behaviour on the A321 (more apparent with high winds like you are experiencing) and the A321’s physics have been tweaked for 19.3 (if I recall correctly). After this tweak, we haven’t seen any more reports of this.
If we get more reports of this happening, I’ll make sure to re-report this to the team. For now, I suggest just to keep an eye out on your device to make sure this rocking does not disengage the autopilot, which may result in unwanted violations. As I said, let’s hope it’s a ‘one-off’, but if not I’m sure someone at the team will look at it.
The Airbus A321 accounts for about 99.9% of all my activity on IF, and I have become very familiar with the intricacies of its its operation. Being an incredibly technologically sound aircraft in real life, the aircraft has its quirks and preferences. Generally, I’ve found this bug to be avoidable by setting my cruising altitude anywhere between FL250 and FL330, depending on the duration of my cruise.
Right now, I’m flying from KBOS-KLAX in the JetBlue A321 (just like you). I’m cruising at FL305, Mach 0.86 and winds are 187° at 43 kts. There has been no rocking.
The 321 is an older model that needs some love. Sometimes simply turning off the heading and turning it back on again will do the trick.
Can we move away from WHERE the plan was made. This is a problem that we have seen before and unless you have some crazy winds it may not be the issue.
Please let us help. If you have no idea or not sure, it’s ok to not reply and let us handle it. Tossing out every single thing to see what sticks is sometimes not the best approach. We have a systematic way of getting the information we need. Extra comments just confuse the user in their support topic.