UPDATE 1-Embraer slashes 20 pct of workforce, cuts spending

* Embraer to slash workforce by 20 percent

* Cuts 2009 revenue forecast to $5.5 bln

* Slashes 2009 investment plans by $100 mln (Recasts, adds details on revenue, investments)

SAO PAULO, Feb 19 (Reuters) - Brazilian aircraft maker Embraer (EMBR3.SA)(ERJ.N) said on Thursday it will lay off about 20 percent of its workforce around the world and cut its delivery forecast for this year, citing a sharp downturn in the aviation market amid the global economic crisis.

With the announcement, Embraer becomes the latest company in Latin America's largest country to slash jobs and scale back production to cope with an economic slowdown that is punishing a wide array of industries around the globe.

Embraer, the world's leading manufacturer of regional jets seating up to 120 passengers, said the crisis forced it to lay off about 20 percent of its total workforce of 21,362 people. That works out to more than 4,200 job cuts.

"As a result of an unprecedented crisis afflicting the global economy, and in particular the aviation industry, it became unavoidable to revise our cost base and staffing levels," it said in a statement.

The company, which also makes business jets and military aircraft, cut its delivery forecast for this year to 242 jets from a previous estimate of 270. In November, it had already slashed the forecast from as high as 350 planes.

With the new delivery forecast, Embraer estimates it will bring in $5.5 billion in revenue in 2009, much less than it had initially expected. It also cut its investment plan for this year to $350 million from $450 million.