Originally Posted by Fat Reggie
there are a couple of different MTGW ups of a thousand pounds if you have the thick skinned wings. I wonder if Viking is going to up the weight limit?
The MTOW increase to either 14,500 lbs (for wheel operations) or 15,000 lbs (for water bombing operations, on floats) is accomplished by way of an engineering order. de Havilland only made that E.O. available to military customers (for the wheel configuration) or to government operators (e.g. state registered aircraft) for the water bombing operations.
There is no intent at all to look at any kind of approval for weights over 12,500 lbs. That would move the aircraft out of FAR 23 and into a different category for both aircraft certification and crew certification, and there's no upside benefit to the manufacturer to go down that route.
The military operators don't have to be concerned about weight because they have no concerns about civil regulations - they can do whatever they want to do. de Havilland didn't certify those military aircraft for operations over 12,500 - they just incorporated the E.O., sold the aircraft to the military customer, and wished them a good day. As for the water bombers - they work on the understanding that if you encounter any problems, you just push a little button on the yoke, and 4 seconds later, instead of weighing 15,000 lbs, you now weigh 9,000 lbs. There are a whole bunch of other issues involved - wing life is reduced, wing tip tanks must be kept full to reduce wing bending moments, etc., but there is really no point in getting into that.