He said they were both conscious "but the worse for wear".
"To free the motor and dash was quite difficult. There is not a lot of room in the plane and when it was concertinaed there was even less, so it was quite difficult to do without hurting the patients. It took us an hour, which to us is a long time, but that's the way it had to be."
Lowe Corporation Rescue Helicopter chief pilot Charlie Beetham said the Cresco plane was removed from around the men and a strop tied to a tractor, to secure the plane should it shift once the engine was removed.
He said he knew the pilot, "which was a bit of a shock".
"When they are fellow aviators, it makes it a bit more personal. He is a well-known and respected pilot."
Both men, who are believed to be in their 60s, suffered suspected fractures to their limbs and "other injuries", St John spokesman Brendon Hutchinson said. They were treated in the plane and lifted straight into the helicopter.
Why the men were landing on Mr Langslow's farm at the start of the day, where there was no apparent fertiliser facilities, was unknown. An industry commentator said it was possible they were returning from a job that had to be abandoned due to weather conditions. There was fog in some parts of the district at the time of the accident.
The crash comes two years after Mr Langslow was convicted of careless driving causing death after a car crash killed a Masterton helicopter pilot. The man was killed when two vehicles collided on Whakapirau Rd, near Maraekakaho.
A CAA spokesman said prevailing weather conditions on Tuesday "and the contributing factors of the accident sequence" would be investigated.
"It is difficult to give an accurate time frame about when the investigation will be completed as there are so many variables in an aviation accident investigation," he said."Often small fragments from the wreckage have to be sent away for forensic examination or component parts sent to the manufacturer to check.
"In some cases we need to have specialist aviation engineers strip down aircraft engines to try and find a possible cause of the accident. It could be up to 12 months before a final report is available."
He said the co-operation of Waipukurau police had been "outstanding".
"We have already received detailed photographs taken by police at the accident scene."
Police guarded the accident scene yesterday, opposite the Otane Cemetery on State Highway 2, north of the town.
Aerospread Ltd owns the downed topdressing aircraft. A statement from its managing director Bruce Peterson said the Civil Aviation Authority (CAA) was investigating the accident.
"Our primary concern is with our injured staff who are listed in critical and serious conditions in intensive care," Mr Peterson said.
"We have spent time with the families at Hawke's Bay Hospital and we ask media to respect their wish for privacy at this difficult time.
"Both of the injured - our pilot and top-dressing loader/driver - are very experienced.
"We would like to thank emergency services and the Lowe Corporation Rescue Helicopter for their outstanding response to this accident, and hospital staff for their emergency care."
