Hello
This was taken from the Manual
AIRSPEED LIMITATIONS
The maximum airspeed with the Bambi Bucket installed during water dump is 90 km/h (50 knots).
AIRSPEED LIMITATION
With an external cargo load VNE shall not exceed 190 km/h (102 KIAS) or airspeeds indicated by ASI VNE index whichever is less.
MANEUVERING LIMITATIONS
When carrying external cargo load the Roll angle is limited to 20 degrees.