The Israeli air force (IAF) has grounded its fleet of Sikorsky CH-53 Yasur helicopters after one made an emergency landing on 16 August.
The CH-53, with a crew of three, landed safely in a field shortly after taking off from Tel Nof air force base. Initial indications point to "a problem in the rotor blades", the IAF says, but an investigation is under way.
Israel's CH-53 fleet was recently upgraded under the Yasur 2025 programme, with the installation of 20 new systems, including advanced electronic warfare systems and a satellite communications capability. The upgrade also included the addition of a unique altitude hold and hovering stabilisation system and a laser obstacle ranging and display system.
Sikorsky has also supplied the IAF with new main gear boxes to replace the current transmission system and the aircraft's hardware has to be monitored closely for cracks because of its age.
The IAF plans to operate its CH-53 fleet until it can acquire the new Sikorsky CH-53K, which is being developed for the US Marine Corps. The IAF says only the CH-53K will meet Israel's requirements.