Boeing warns of engine icing risk on 747-8s, Dreamliners

[flee 5]

Boeing warns of engine icing risk on 747-8s, Dreamliners

 

Boeing (BA.N) advised airlines on Friday about a risk of engine icing problems on its new 747-8 and 787 Dreamliner planes with engines made by General Electric (GE.N), urging 15 carriers to avoid flying them near high-level thunderstorms.

The warning led Japan Airlines (9101.T) to pull 787 Dreamliners from two international routes. Other affected airlines include Lufthansa (LHAG.DE), United Airlines, an arm of United Continental Holdings (UAL.N) and Cathay Pacific Airlines (0293.HK).

"Boeing and JAL share a commitment to the safety of passengers and crews on board our airplanes. We respect JAL's decision to suspend some 787 service on specific routes," a Boeing spokesman said.

The move followed six incidents from April to November involving five 747-8s and one 787 when aircraft powered by GE's GEnx engines suffered temporary loss of thrust while flying at high altitude.

Full report: http://www.reuters.com/article/2013/11/23/us-airlines-boeing-idUSBRE9AM03G20131123

Edited November 25, 2013 by flee

[Cire 0]

Another icing episode that involved a Boeing. The last air crash case were icing formed in fuel pipings leading to the RR engines of the B777 that saw the crash landing of the BA's 777. According to aircrash investigations, formed clumps of ice in the fuel pipes were unclogged during throttle opening, in which it then floats down the system and sticks to the heating elements of the engine's fuel warmer protruded pipings. The ice blocked further fuel deliveries to the engines during the aircraft descend. This explains why the pilots were unable to raise the engine power of the aircraft causing the aircraft to crash landed at the tip of the runway. In this incidence, it was fortunate that all the passengers and crews were safe.

 

I wondered whether the latest case is similar to that of the RR engines which have since modified its heating element design.

[flee 5]

This problem affects only the GE engines.

 

Early reports indicate that ice crystals forming behind the main engine fan gets ingested into the turbine core and may cause a flame out if too many of them gets inside.

This usually happens during cruise, when engine fan speeds are low.

[Smiley 0]

Yes, this is different to the 777 event. Ice is getting into the internal parts of the engine and causing damage. The 777 had ice in its fuel system.

 

On a related subject, one of the international routes JAL have pullled the 787 off of was Tokyo - Changi.

 

Steven

[flee 5]

GE says it is now accelerating an effort to solve the icing problem by modifying software for the full authority digital engine control (FADEC) systems. The software change will add a tweak to the aircraft’s debris rejection system – originally intended for birds and rocks but not ice. The goal is to prevent ice from entering the compressor and causing a stall. Variable bleed valve doors stationed ahead of the compressor section will open at scheduled moments, allowing any ice crystals to be ejected before reaching the engine core, according to GE.

 

Full report: http://www.flightglobal.com/news/articles/genx-icing-issue-prompts-747-8-787-restriction-route-withdrawals-393439/

[Sandeep G 1]

Another "software" glitch/problem....

Me thinks simple mechanical (albeit weighty) are more robust and reliable.