LONDON — Britain's fleet of Sentry E-3D early warning aircraft has been effectively grounded while the Royal Air Force (RAF) rectifies electrical wiring and other issues on the aircraft.
The six-strong fleet of aircraft has been affected for weeks, and the issue has resulted in Britain's allies having to step in and fill the gap on operations for NATO and the coalition mission against the Islamic State group in Iraq and Syria.
The RAF has one Sentry normally based in Cyprus as part of the British contribution, known as Operation Shader, to the mission againt ISIS.
"As a result of routine technical inspection on RAF E-3D aircraft, an issue has been identified related to the integrity of the electrical wiring and cabin conditioning system. Safety remains our paramount concern; therefore, the Sentry fleet will only fly again once the ongoing rectification work is complete," a spokesman for the RAF said.
Sources said it could be several weeks before the fleet starts operations again.
Typically the RAF only has a portion of the fleet available for flying, with the rest in deep maintenance.
Earlier this year, the Ministry of Defence (MoD) said it had four aircraft in its forward fleet and two in sustainment, or deep maintenance.
The rectification work is being undertaken at the Sentry's temporary base at RAF Coningsby in England.
The aircraft's normal headquarters at Waddington remains closed to large jets while a new runway is installed at the RAF base, which also is home to Sentinel, Airseeker, Reaper and other ISTAR assets. The aircraft are not technically grounded but are rather unservicable.
The Sentry was due to be taken out of service in 2025, but the British announced in their Strategic Defence and Security Review last year that the aircraft's service life was being extended by a further 10 years to 2035.
The extension is expected to result in a major update around the end of the decade to maintain their effectiveness.
Northrop Grumann UK leads a consortium responsible for the maintenance and availability of the aircraft.
It recently signed a nine-year extension to the support contract.
An MoD source said the technical issues were unrelated to the Northrop Grumann support effort.
Other nations are not thought to be affected.
Andrew Chuter is the United Kingdom correspondent for Defense News.
