A Royal Air Force Chinook has been stuck in an Oxfordshire field for days after making a precautionary landing due to a mechanical issue.
The helicopter from 28 Squadron, based at RAF Benson, sank into soft ground in the field near Wantage on Tuesday, the station said.
RAF Benson wrote on its Facebook page on Thursday that engineers were deployed to the site to assess the mechanical issue, which has now been fixed.
However, the "extremely soft ground", likely caused by recent wet weather, has posed more of a problem and made the recovery of the Chinook "very difficult".
A tri-service team of specialists is now working to safely extract the aircraft from the field.
The base wrote: "While it was hoped that it could simply be dug out and then flown home, the risk of damage to the aircraft from this course of action has been assessed as significant and alternative options are being explored, including potentially lifting it from the mud with a crane.
"We hope to have the aircraft home by the end of the week."
The base also said it is "extremely thankful" to the landowners for their "understanding and support".
Giving an update on the RAF's progress with the Chinook rescue, Flight Lieutenant Cameron Stuart of 28 Squadron told Forces News they had been assessing "various options" but looked likely to settle on using cranes.
"We've got five or six options we've looked at," he said.
"We don't want to look at damaging any of the parts of the aircraft that might currently be stuck in the mud. There is a little bit of digging involved. The option we think might be the safest is to lift it out with cranes."
Chinooks are primarily used by the Royal Air Force for trooping, resupply and battlefield casualty evacuation.
The aircraft's heavy-lift capability means it can lift or carry a range of freight, including vehicles, 55 troops or up to roughly 10 tonnes of mixed cargo.