The payload of a modern agricultural aircraft is more like 1800kg.
For his dedication to the aviation industry, Kelly received an award from the New Zealand Aviation Pilots and Owners Association - the organisation he helped set up in the early 1970s.
Kelly was born in Invercargill and began his aviation career in Timaru, forming Southair at the Taieri Airfield in 1964.
The company is still in business, specialising in servicing agricultural aircraft.
However, Kelly recalls the company "going broke" in 1984 when the government devalued the New Zealand dollar.
"There were several people that went broke at that time - quite a number of prominent people who are still in business today."
Kelly said the company survived and he continued on as part owner until selling in 2004.
He moved to Wanaka in 1996, working as an inspection authority, and continues to do so occasionally.
Kelly stopped flying five years ago and recalls a career of 2000 flying hours with three forced landings due to mechanical failures.
"It doesn't happen to that many people, and certainly to an engineer to have mechanical failures is not good, but they weren't mine.
"They were other people's problems."
Kelly said such events were "life in general aviation".
"We have our ups and downs, literally."
Kelly has been a member of Lions for 50 years and continues to play golf "badly".