Do you need a visa if stopping to refuel in Beijing then stopping over at Baiyun?

My grandmother is flying to New Zealand next week.
Her plane stops to refuel at Beijing Capital airport then flies into Baiyun Airport at 19.45 on 3rd December.
Her connecting flight to New Zealand is at 00.30 next morning (5 hour stopover).
She has been told that she needs a transit visa because of the refuelling stop, is this true?
She is quite old and there is not much time left to get one.