Our birds have a flap asymmetry system which we check by jumping out the terminal board after the wing box.
Also the hydraulic system on our plane has to be deep pressurized in order to reset the emergency flat brake
Fuel nozzle leakage.
New Engines or those with newly overhauled fuel nozzles sometimes experience this.
We found that our overhaul facility was not doing all the checks on the nozzles they were sending us, so we were getting back nozzles that would lead around the head and make the air-conditioning smell really bad.