I am actively involved in fire scanning the Queensland fires.
Last Wednesday I was standing on the tarmac at Rockhampton airport. While we watched a large and intense fire started to the west of Rockhampton, near a town of 8,000 people, called Gracemere. The B737 water bomber was on the tarmac. It was already filled with its load of water, and the crew quickly started up and taxied out. It flew to the fire field at 2,500 feet, and visible all the while, made its run over the fire. We could not see the actual drop. A short time later it emerged from the cloud of smoke and tracked directly to a close left base for a landing to the north west. After taxiing to the tarmac it was parked as closely as possible to the water hydrant, the left engine was left running, the hose attached and the water onloaded, and the aircraft departed again. This took about 25 minutes. This procedure was repeated three times while we were there. The fire was quickly extinguished.
The town of Gracemere was evacuated because the wind was blowing the fire directly towards it.
In my opinion, the professionalism of the crew, and the efficient design of the aircraft saved every house in Gracemere.
The fact that it is an old airframe, with many hours and cycles is irrelevant. The fact that it has been modified to be an effective water bomber and it is operated by a well trained professional crew is the important aspect. I would say that every resident of Gracemere is grateful for that aircraft.