Tauranga's longest serving top-dressing pilot is today retiring after 53 years in the job and 32,000 hours in the air.

Derek Williams prepares for his final flight as a commercial top dresser pilot. Photo: Tracy Hardy.

Derek flies through the traditional water spray as he leaves Tauranga Airport.

Derek Williams sat on the grass at Tauranga Airport this afternoon smoking a cigar 'to calm the nerves” before making a final flight to Hamilton in his PAC Fletcher FU-24 top dresser.

Derek's retirement was not by choice, but rather a result of circumstance after employers Super Air decided the plane would be put to better use in Kaitaia.

'The work has slowly died off here so it makes sense for the company,” says Derek.

'I'm on hand to do something if it's required, but officially this is it.”

The 76-year-old Mount Maunganui resident is leaving a heavy stamp on the region's aviation industry, with his 53-year career offering impressive statistics.

Since earning his pilot's licence in 1955 and beginning as a top-dressing pilot in 1961, Derek has spent about 32,000 hours in the air, made about 592,000 take-offs and landings and sprayed 363,448 tonnes of fertiliser across 57,000 hectares.

'I've got a saying, that I've never had a real job. I've sat on my ‘A' doing what I love doing.”

Despite his passion, it's a job he's thankful to have survived, as a lot of his friends and colleagues have not.

'I have a lot of sad memories, it's a dangerous operation. Particularly in the 1960s and 70s, it felt like we had a funeral every week.”

He says such accidents were mostly down to lack of aeroplane performance or bad airstrips.

Statistics given to SunLive from Derek show 100 agricultural pilots lost their lives during 1949-1980 (3.2 per year) while 47 died between 1981 and 2012 (1.5 per year).

'Top dressing has become safer over the years. These aeroplanes came out originally with 225hp which is underpowered as heck.

'This [Derek's plane] is a 400hp. The aircraft performance has increased three-fold.”

Super Air has employed 14 pilots since its creation 25 years ago. It has lost seven pilots and one loader driver.

Derek himself has had 'a lot of near misses” and two serious crashes. In 2000 he wrote off a Fletcher plane in Cambridge, but managed to escape without injury.

'The engine seemed to lose power and I went off the strip, I hit something and it went all dark. When I stopped I thought I must be dead.

'But I opened the canopy, the engine was ripped out, and I had gone through a trough and the muck on the bottom had covered the aeroplane.”

A second crash in 2001 in Northern Borneo resulted in his plane bursting into flames. Again, Derek was uninjured.

'I've said before - I've now run out of adrenaline,” he says.

Today, as he departed Tauranga Airport, its emergency services carried on its tradition to farewell retirees by spraying water over the plane as Derek entered the runway. He received the same treatment on arrival in Hamilton, where a farewell event is on this evening.

Retirement doesn't mark the end of Derek's time in the sky – he is the owner of ex-RNZAF Harvard 91 and plans to continue flying that as long as he can.

See the video for more information, and footage of Derek's final top dresser flight.