This is a question about PEY headphone adapter on the A350-900.

My colleague just flew PEY on the A350 for the first time. He's got the QC35, but reported he could not plug in. He claimed the jack on the PEY seat was dual prong with a 3.5 mm jack and a 2.5 mm jack. I have not heard of this before. I told him he should have just tried plugging into the single 3.5mm jack to see if that works. He will confirm in a few weeks on the return flight.

Anyone have insight on this? I've not heard of this configuration before.