Big effort from the little helicopter that couldn't

A helicopter tries to drag the Cessna 172 plane off mudflats at the mouth of the Wairoa River near Clevedon. Picture / Martin Sykes

A light aircraft which crash-landed on mudflats near Clevedon yesterday proved stubbornly hard to retrieve.

The five-year-old plane came down around lunchtime after encountering a flock of birds. Two men on board, experienced pilots in their 20s, escaped with minor bruises.

It did not take long before the tide had risen and the wreckage was submerged, with only the tail poking out of the water.

An attempt was made to salvage the plane a couple of hours later when a diver jumped from a helicopter and attached straps. Another helicopter tried to drag it out of the channel but failed.

"It's so full of water, it's too heavy for us," said pilot Richard Stening.

The pair on the aircraft were winched from mud at the mouth of the Wairoa River by the crew of police helicopter Eagle.

The men from Ardmore Flying School were on training manoeuvres in a low-flying area when they encountered a flock of birds, said general manager Craig Hunter.

"In the process of taking [evasive] action we believe they possibly stalled ... and made a gentle descent into the water."

They made a controlled landing and "went for a swim" in the sea. "The senior instructor is shaken but pleased to be having a coffee."

Mr Hunter said the $300,000 Cessna 172 would have been flying around 30m above the sea.

The plane is expected to be salvaged today for inspection.