A light aircraft that crashed last month, fatally injuring its two occupants, was seen by witnesses disintegrating in the air and spiraling downwards, according to an investigation.

The flight led to the deaths of Peter Tawse, 61, and John Finnan, 58, on 6 October last near Duncormick in Co Wexford. It was the second flight that had been operated in the Rollason two-seater that day from a nearby airfield.

The crash happened shortly after 4.30pm and left the wreckage of the destroyed aircraft strewn across a number of fields in the rural area, according to a preliminary investigation report published by the Air Accident Investigation Unit.

The report does not come to any conclusions or contain any analysis of why the crash happened, but will be followed by a full and final version in the coming months.

According to the report, the flight was operated by pilot John Finnan from Co Kildare in the left-hand side, and instructor Peter Tawse from New Ross in Co Wexford on the right hand-side. The instructor had earlier been on a different flight with another pilot in the same craft, from the airfield at Taghmon.

Aircraft handling and performance throughout the earlier flight was normal, with no anomalies.

The report says that before the accident, the instructor was heard to remark to the pilot: "I suppose I better take the loose bits out of it".

It says the pilot said to another pilot: "I'm going up to do spins", before being seen to carry out a "full outside check" with a checklist in his hand.

They left the airfield at about 4.10pm that Sunday afternoon, heading south initially, then turning south west and circling back around while climbing.

At about 4.40pm, "witnesses reported that the aircraft had emitted a loud noise and disintegrated in the air," in the Duncormick area. The report said that local persons and emergency services proceeded to the scene and determined that both occupants had been fatally injured.

There was no fire, but the aircraft was destroyed. Emergency services were quickly on the scene, with inspectors from the AAIU arriving later that night to be begin their investigation.

The scene of the crash in the Duncormick area of Co Wexford

The two occupants of the aircraft were found about 50 metres from the main wreckage.

According to the report, the approved flight manual for the Rollason aircraft, which was made from wood and fabric in England in 1965, says that operations are "limited to normal flying manoeuvres" and that "no aerobatic manoeuvres, except spins, are permitted".

One witness spoken to by the AAIU reported that the aircraft "executed a number of consecutive roll manoeuvres" while several witnesses reported hearing "waxing and waning engine sounds, as the aircraft manoeuvred". Others reported that immediately prior to the accident, the aircraft "executed three loop manoeuvres".

During the descent from the third loop, two loud noises, which were described as bangs or cracking sounds, were heard. Parts were seen to separate from the aircraft and it began spiraling downwards.

"The investigation is ongoing and a final report will be published in due course," the AAIU has said.