Lufthansa is temporarily restricting the operational envelope of its Boeing 747-8 fleet and may change the aircraft assigned to individual flights, after the airframer notified airlines that General Electric GEnx engines could suffer thrust loss due to ice-crystal build-up.
Aside from maintaining a distance of at least 50nm from high-altitude, convective weather systems – as mandated by Boeing for GEnx-powered 787s and 747-8s – the German carrier has also reduced the maximum altitude for flights in icing conditions to 30,000ft (9,100m). This is to become effective from December.
Meteorologica data is analysed with particular care for 747-8 flights, says Lufthansa. If this reveals restrictions on a route, it adds, the 747-8 may be swapped out for other types such as the carrier’s CF6-powered 747-400s.
Meanwhile, UK-based cargo carrier Global Supply Systems – which operates three 747-8 freighters on behalf of British Airways World Cargo – says the directive will have "not much effect" on its flights.
The airline has informed its pilots of the mandatory restrictions but has no plans to deploy other aircraft, it says.
GE plans to resolve the issue through a software change to the engine’s full-authority digital engine control system in the first quarter of next year.