Originally Posted by
SamuelDonuts
It’s to do with the oceanic airspace requirements in terms of radios. Any aircraft operating in that airspace must have a certain type of radio/software installed for comms and position reports, and not all of the Boeing fleet have it. Someone else might be able to explain it better than me.
In early 2021, ICAO mandated that all flights operating at higher levels within NAT-HLA airspace must have a CPDLC and surveillance capability. The only exception to this were routes defined as Special Routes such as Tango 9 and Tango 290.
NAT-HLA airspace requires technology know as FANS (Future Air Navigation System). Unsurprisingly the 737 isn't equipped with this kind of hardware/software by default. Jet2 has been working with a supplier to develop the required hardware/software and it will eventually be fitted to approximately 60 737s.