Joe:

You say that engine run ups are done "to ensure that repairs that have been made to an engine are satisfactory." 

We have been told that run ups are required as part of regular maintenance.  After a number of hours in the air every plane is required to go through a number of tests to ensure its engines are working properly and can be operated safely.  The run ups are part of that regular maintenance.

Is that not correct?

If the run ups are being done only after engine repairs, there must be a lot of repairs to these Q400 aircraft, because we are drowning in the noise of engine run ups along the Waterfront.

Bill Freeman