RAF fleet of Sentry aircraft grounded by electrical fault
RAF surveillance aircraft being used in the fight against so-called Islamic State have been grounded following the discovery of an electrical fault.
The fleet of six Sentry E-3D, including two assigned to help the air campaign in Syria and Iraq, could be out of action for several weeks, the RAF said.
The fault was discovered during routine technical inspections, it added.
It is the second time in four years the planes, based at RAF Waddington in Lincolnshire, have been grounded.
BBC defence correspondent Jonathan Beale said the two Sentry aircraft had been providing airborne co-ordination as part of the operation against IS, and were helping to prevent other coalition aircraft coming into conflict with each other.
That work is currently being carried out by coalition allies while the fault in the RAF fleet is rectified, he added.
An RAF spokesman said: "As a result of routine technical inspections on RAF E-3D Sentry aircraft, an issue has been identified relating to the integrity of some electrical wiring and cabin conditioning systems.
"Safety remains our paramount concern, therefore, the UK Sentry fleet will only fly again once the ongoing rectification work is complete."
In April 2012, one of the aircraft - which provide early warning and fighter control systems - was found to have a technical issue.
The Sentry fleet was grounded for almost two weeks before being given permission to fly again.
- It has four CFM 56 2A-3 turbofan engines
- Each gives 24,000lb of thrust
- Maximum speed of 460 knots
- It measures 46.68m in length, with a wing span of 44.98m
- It holds 18 aircrew
- It can travel as high as 35,000ft
Due an upgrade
The aircraft make is used by a number of other air forces across the world, including the US, France and by Nato.
The MoD announced plans last year to upgrade the fleet in 2020 and extend their lifespan to 2035.
But according to defence specialists at IHS, all other countries which operate the aircraft had already upgraded them, but the MoD cancelled plans to do so in 2009 because it was "unaffordable in the current financial climate."
A defence source told the BBC there had been "incremental upgrades to the fleet to meet defence requirements" and the current issue was found during routine inspections.