Glekichi,
the problem with Jetstreams is that when you get them wet, things go wrong.
Google "Lucas Electrics".
We had huge problems with them at Eastern (with many spurious stick shaker events), almost on a daily basis until Eastern got rid of them.
It got to the point that the fleet was going to be grounded by QF, failing an answer.
BAe were unable to come to a feasible conclusion as to why these problems were occurring in 1995/6.
It seems that 15 years later, BAe still don't have the answers.