Giovanni Cento Nove I guess you are wrong.... bearing in mind that engineers who have worked on them have already posted. There may be a mix across the fleet, but the BK117C1 has a Kawasaki KHI KB03 anyway.
The choice of the BK as the core of this question was honed in on the box.
As for Silsoe Kids comment about about changing records perhaps he has a view on the subject.
Perhaps he has not asked why the K boxes are causing problems 'all of a sudden' when it now seems pretty clear that other boxes by the same manufacturer have displayed anything but weakness.
Do you NEVER ask questions?
How do you hope to get answers?