ACC ESS FEED (A321)

777Driver · April 29, 2026 at 1:11 AM

Apologies for so many questions. I noticed ACC ESS FEED doesn't automatically switch; this is how the older fleet used to work until a bunch of serious incidents involving gen faults.

This British Airways A319 incident is the most well-known - https://www.gov.uk/aaib-reports/a…rce=chatgpt.com

I'm wondering if the switching is coded, or if I'm doing something wrong. I simulated TR1 failing; some spoilers and SECs went offline. I assumed that the aircraft auto switches the ACC ESS FEED and restores power. I had to switch it manually to restore systems

Jet-Pack (IPACS) · April 29, 2026 at 8:15 AM Official Post

I'd have to look into the code if I added this or not.

But from the top of my head: If the ACC ESS FEED did not switch then all screens should go black in the cockpit (apart from backup), shouldn't it? Or is there still AC2, I'd have to check... The fact that only some spoilers and SECs go offline might be a different issue.

777Driver · April 29, 2026 at 10:57 AM

I'll check when I am home tonight, with a full gen failure. I only failed the Transformer rectifier, it was enough to kick A/THR offline as well, so I (assumed) auto switching would make sense in that scenario too

777Driver · April 29, 2026 at 10:43 PM

I did a small test. Failed the Bus Tie, then turned off Gen 2. All screens went dead, switched to ALTN on the overhead, and everything came back with AC2 Bus 2 Fault.

So I think the current logic is like the older A320-214. I still could be wrong, so many variants and revisions.

In the scenario above, at night, you would be in darkness, trying to read the QRH