I seem to remember that when BA reintroduced microwave ovens ( yes they had them on the original 747 classic) the cost was around £50k per oven!
Now you can buy a pretty reasonable microwave oven in the UK for under £100 so the cost was on the certification process I guess.
Shortly after fitting one crew member blew one up and the excrement really hit the fan. Not the oven fan I hasten to add
