* Profit down 19 pct from year ago on weak deliveries
* Shares fall 4 pct to six-month intraday low
By Brad Haynes and Roberta Vilas Boas
SAO PAULO, Oct 31 (Reuters) - Brazil's Embraer SA posted an unexpected drop in quarterly profit on Thursday due todelayed aircraft deliveries, but the world's third-largestcommercial planemaker stood by its 2013 forecasts on hopes for astrong fourth quarter.
Third-quarter net income fell 19 percent from a year earlierto $52.9 million, according to a securities filing, missinganalysts' average estimate of $75 million in a Reuters survey.
Embraer delivered 58 planes to airlines in the first ninemonths of the year, less than two-thirds of its full-yearforecast of 90 to 95.
"Our third-quarter numbers were a little below what weexpected because of some delayed deliveries," Chief FinancialOfficer Jose Antonio Filippo said on a call with reporters. "Westill confirm our annual delivery guidance - obviously, at thebottom end of that range."
Embraer shares fell more than 4 percent in Sao Paulo to asix-month low as the weak results underscored questions aboutthis year's profitability targets.
Earnings before interest, taxes, depreciation andamortization, a gauge of operating profit known as EBITDA, fell7 percent to $156.4 million, missing analysts' average estimateof $172 million.
EBITDA as a share of net revenue, a measure of profitabilityknown as the EBITDA margin, came to 12.1 percent, little changedfrom a year earlier, when the restructuring of a customer'sfinancing weighed on results.
Embraer's 11.7 percent EBITDA margin in the first ninemonths of the year is far short of its target of 13 percent to14 percent for 2013.
The EBIT margin, another profitability gauge that includesdepreciation and amortization, was 6.4 percent throughSeptember, well below the 9 percent to 9.5 percent target.
Filippo said the company still expects to meet its EBIT andEBITDA targets on the basis of a strong fourth quarter.
Embraer initially reported earnings in Brazilian reais,using accounting standards that showed a 10 percent drop in netincome from a year earlier.
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