Royal Navy pilots complained about being 'overworked' and of 'woefully unreliable' helicopters before a tragic crash earlier this month, the Mail can reveal.

Instructors also asked for more time to train students before a fatal accident which killed three crew members and destroyed their ageing Merlin.

Lieutenant Commander Chris Gayson, 42, Flight Lieutenant Lily-Mae Fisher, 31 and Petty Officer Owen Green, 24, died when their chopper, callsign 'Sword 01' crashed in a field in Somerset on 3rd June.

The tragedy was the second to strike the same Royal Navy unit in three years, following the death of helicopter pilot Lieutenant Rhodri Leyshon on a training flight in September 2024.

Last night, a whistleblower from their Royal Navy Air Station said students were being rushed through courses and that safety was being compromised for the sake of schedules.

Officers are also working for longer than their allotted hours to meet deadlines set by senior officers while helicopters are repeatedly breaking down, according to the source, who spoke on condition of anonymity.

They said: 'The families deserve to know the truth. They push us and push us until we break. Mistakes are made and mistakes are fatal.

'We are overworked and tired. We are a danger to ourselves and to the public. We have families and four deaths in 18 months in our group is too much.

'The students are not being trained correctly. They're being rushed through.

'The fear among pilots is that no one has their back. That they are expendable. That the higher ranks don't care about their people at all.

'Yet despite the latest crash they are expected to resume their duties. It is not their fault they're not ready. Safety is being compromised and the Merlins are woefully unreliable.'

The Mail has learned an initial investigation into the latest fatal crash has ruled out a mechanical breakdown.

That interim finding is based on an examination of the AgustaWestland helicopter's black box recording device that was recovered from the scene near Sourton Down, Devon.

All three persons onboard lost their lives, including the course instructor. According to the whistleblower, Lt Cmdr Gayson was flying additional sorties in a bid to ensure students qualified on schedule.

The whistleblower said Gayson was an outstanding instructor whose safety concerns had been overlooked.

The victims' families are receiving progress reports about the investigation. Measures to reassure aircrews have also been taken.

Royal Navy commanders told grieving relatives by email: 'The squadron has undertaken a series of engineering and aircrew forums to allow an open and honest discussion regarding changes we could make to enhance our processes. These discussions have led to some immediate changes taking place.'

Fl Lt Fisher was on the final assessment of her flying training when she was tragically killed. According to defence sources she was due to be awarded her pilots' wings.

Gayson joined the Royal Navy as a Warfare (Pilot) Officer in 2008 and had flown in Norway, Jordan and Afghanistan in support of UK commando operations.

At the time of his death Gayson was the Operational Conversion Flight Commander on 846 Naval Air Squadron based at RNAS Yeovilton, Somerset.

The helicopter had entered service in 2002. Other Merlin flown by the Royal Navy are of similar vintage.

The whistleblower continued: 'Courses are behind schedule because of the unreliability of the aircraft. For so many reasons, they won't start and the levels and readings are incorrect. Sorties are cancelled daily because of engineering, mechanical or technical issues.

'Pilots are anxious about returning to their duties. They want to see the crash reports. Flights will not be able to go ahead without sufficient air crew available.

'Since the accident many complaints have been made about working conditions, particularly flying hours, being forced to fly on the limits of hours, and of weather conditions, to get courses through on time. On the day of the crash we were forced to go up in bad weather.

'Previous complaints about unserviceable aircraft and students not being ready to graduate were denied by senior officers. Changes need to be made.'

An initial triage investigation by the Defence Accident Investigation Branch has been completed. The incident will be the subject of a Service Inquiry which could take several months to complete.

Having been paused following the crash, Merlin Mk4 flying was authorised a week later.

Last night, the Ministry of Defence said: 'Our thoughts remain with the families, friends, and colleagues of Lt Cdr Chris Gayson, Lt Lily-Mae Fisher, and PO Owen Green during this profoundly difficult time.

'A Service Inquiry has been convened to investigate the Merlin helicopter incident. It would be inappropriate to comment further at this time.'