I'm currently facing the joy of trying to use Avios to book Avianca flights via IB+ which has led me to this thread. So far, I've called the IB call centre three times, to be told "we don't deal with Avianca", "you can't redeem on Avianca, only earn" etc.
I've checked via ANA and seen that there is plenty of availability, but given that the agents say it's not possible, I can't be sure if the response of "nothing available" is down to AV not releasing seats to IB+ or simply the agent searching with the wrong parameters...
Anyway, since then I came across
this blog post which claims that:
"Iberia doesn’t restrict the flights that can be booked with oneworld partners, but there are restrictions on the flights that can be booked with non-alliance partners. As a general rule, the flight needs to either originate or terminate in Spain or needs to be booked in conjunction with an Iberia flight. For example, Interjet flights can be booked within Mexico, but only in combination with a flight operated by Iberia. This rule applies to flights on Vueling, Level, Binter Canarias, Meridiana, Royal Air Maroc, Avianca (TACA), and Interjet."
Does anyone know if there is any truth in this statement? I can't see anything to this effect on the IB+ pages...