AN Air Corps jet could have flown liver transplant girl Meadbh McGivern from Sligo to London in just over an hour -- but the HSE turned down the offer.
Instead, HSE officials opted for a Coast Guard S61 helicopter, the slowest option available, to transfer the 14-year-old.
However, the flight from Sligo never took place and the teenager missed the transplant opportunity. The liver went to another patient.
The Air Corps has confirmed that the Gulfstream G4 government jet was back in Baldonnel at 10.30pm on Saturday, bringing President McAleese home from the royal wedding in Monaco.
The Air Corps received a request for an aircraft at 7.45pm and told the HSE that none was available at that time, but that the Gulfstream would be back in Baldonnel by 10.30pm.
"The Air Corps was informed that this option would not be required and that alternative arrangements would be made for the patient transfer," a Defence Forces spokesman said.
A stand-by Air Corps helicopter, which is available 24 hours a day to answer HSE requests, was deployed on an Air Ambulance mission taking a spinal injury patient from Kerry to Dublin at the time.
"An alternative helicopter transfer was not possible as Heathrow Airport is beyond the night-time flight range of the (Air Corps) AW139," he added.
An inquiry has now been launched into the incident, and so far the HSE has failed to explain why the Coast Guard helicopter was preferred over the faster Gulfstream jet.
The Gulfstream would have taken about 30 minutes to fly from Baldonnel to Sligo and one hour, 15 minutes from Sligo to London, while the McGivern family was told the Coast Guard helicopter would have taken four hours to get to London.
When Kings College Hospital was told of the flight time of the Coast Guard S61 chopper, the family was advised that there was no point in travelling because Meadbh would have had to be in London by 2am at the latest to avail of the transplant.
She could also have been moved by road to Baldonnel to meet the Government jet, but this possibility does not seem to have been considered.
Health Minister James Reilly has apologised to the McGivern family for "the traumatic events that have led to this lost opportunity".
An inquiry into the blunder is to be carried out by the Health Information and Quality Authority (HIQA).
The Gulfstream jet, which would have made the journey to London with time to spare, was one of four transport options to get the teenager from Ballinamore in Co Leitrim to Kings College Hospital in London.
Taoiseach Enda Kenny said he felt "absolutely distraught" as a parent in light of the experience of the McGivern family.
"I think it's fundamental that we find out the accuracy of what happened here which results in the little girl not being able to travel to London for her liver transplant and to put in place a system that makes sure that never happens again," he said.
Under the terms of a Service Level Agreement with the HSE, an Air Corps helicopter with specialised medical equipment is on standby 365 days a year for Air Ambulance missions.
The Air Corps have completed 41 Air Ambulance missions so far in 2011.