Yes, I suspect any foul play in the Pakistan International Airways flight crash. Pakistan is an unstable country that has a history of violence and terrorism. It is completely reasonable to believe that the recent Pakistan Airlines flight crashed as a result of terrorist activity. This would not be the first time something like this has happened.
Pakistan may have a very poor record when it comes to things like Health and Safety Regulations but from what I've read on the story there has been nothing so far to suggest negligence, foul play or problems with regulations. Until the final reports on compiled though it is not possible to fully rule foul play out.
Each day, hundreds of planes fly in and out of any given airport. This happens at literally thousands of airports all over the world. Any more, plane crashes are relatively rare. It is much more common to get hurt in a car crash than it is to get hurt in a plane crash. The Pakistan crash was likely because of mechanical failure.
No, I do not suspect foul play in the Pakistan International Airways flight crash that just took place. The pilot sent in a distress signal after losing an engine. Often, a plane can still land with one engine out. However, when flying over mountains, it becomes more complicated. The contour of the land is uneven. The winds are more erratic. A lot could have gone wrong. I believe there was no foul play; there was just engine trouble in harsh terrain, resulting in this tragedy.