GE GE Aerospace

By Andy Pasztor 

General Electric Co. engines powering as many as 150 Boeing Co. 787 jets world-wide are susceptible to sudden in-flight shutdowns due to internal ice accumulation, prompting U.S. regulators to order swift fixes to eliminate the danger.

A Federal Aviation Administration safety directive released this week indicates that certain upgraded models of General Electric's most advanced engine pose an unacceptable safety risk because internal ice buildup -- detected in one recent incident at an unexpectedly low altitude -- could result in both engines of a 787 shutting down simultaneously. According to the agency, the possibility that engines couldn't be restarted "is an urgent safety issue."

There haven't been any accidents stemming from the problem, but red flags were raised when one engine on a Boeing 787 shut down on its own and couldn't be restarted while flying at roughly 20,000 feet. The other engine on the plane, flown by an unidentified airline, was an older design and continued to operate, according to the FAA.

The problem cropped up after many years of intense efforts by General Electric and other engine makers to prevent different types of shutdowns stemming from internal icing while cruising at much higher altitudes. General Electric previously revised the design of some of its engines to cope with those safety challenges.

Boeing and General Electric have been working on the latest issue for months, and the engine maker has issued voluntary service bulletins spelling out maintenance efforts and fixes that it estimates already have alleviated low-altitude icing hazards on some three dozen Boeing 787s.

But the FAA's move requires special notices to go out to pilots within a week, alerting them about revised operating procedures to cope with potential low-altitude icing problems. Within five months, carriers must fix or replace at least one of the suspect engines on all affected 787 Dreamliners, according to the agency document released Thursday.

The FAA determined that mandating a faster compliance deadline could unduly disrupt operations of more than 150 airlines, and potentially even cause airplanes to be grounded. A General Electric spokesman said the company was working with customers to avoid schedule disruptions. The fixes are expected to be done during normally scheduled maintenance, without having to remove engines. But the FAA has left open the door to possible further fixes.

The directive, slated to become effective in two weeks without pubic comment, covers 43 planes operated by U.S. carriers. But it is eventually expected to be followed by regulators around the globe.

Highlighting the extent of potential hazards, the FAA ordered cockpit crews to brief specific ice-removal procedures before the first flight of the day for all affected 787 Dreamliners. And when flying through certain ice-prone conditions above 12,500 feet, the directive requires pilots to briefly rev up each of the engines every few minutes to avoid excessive ice accumulation.

In March, following the single engine shutdown event, the FAA issued a similar directive but that affected only a handful of planes.

Write to Andy Pasztor at andy.pasztor@wsj.com

(END) Dow Jones Newswires

April 22, 2016 10:32 ET (14:32 GMT)

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