Shares of Bell Helicopter's parent company, Textron, tumbled the most in nearly three years Wednesday after cutting its 2013 profit forecast as demand for Cessna jets declined.Fort Worth-based Bell saw first-quarter revenue decline $45 million to $949 million and profit fall 11 percent to $129 million.The company said that it delivered one fewer V-22 tiltrotor aircraft to the military in the quarter but that deliveries of commercial helicopters increased to 40 from 30 a year ago.Overall, the manufacturer of aircraft, auto parts and military equipment said quarterly net income rose less than 1 percent to $119 million, or 41 cents a share, from $118 million, or 40 cents, a year earlier.Excluding discontinued operations, profit was 40 cents a share, trailing the 45-cent average of estimates compiled by Bloomberg News.Textron shares (ticker: TXT) fell 13.4 percent to $25.41, the largest intraday drop since May 2010.Textron, based in Providence, R.I., forecast annual earnings from continuing operations of $1.90 to $2.10 a share, down from a January outlook of $2.10 to $2.30 a share.The company also said it expects to turn fewer Cessnas over to customers than in 2012, without giving a number.First-quarter shipments of the aircraft slid to 32 from 38, and the unit posted an $8 million loss."We are adjusting production schedules and implementing other appropriate cost actions at Cessna," Chief Executive Scott Donnelly said in a statement."While we are taking these immediate actions, we believe the global business jet market still has significant long-term growth potential."Bell, in the midst of a $230 million expansion of its east Fort Worth campus, said its backlog at the end of the first quarter was $7.08 billion, down $386 million from the end of 2012.Textron, which gets about a quarter of total sales from Cessna aircraft, "remains committed" to introducing the M2, Sovereign and Citation models this year, as well as the Latitude in 2015 and the Longitude in 2017, Donnelly said."Investing in Textron on the basis of a belated pickup in business was always a bit of a leap of faith, and this weak quarter for business jets is likely to again test investors' confidence," Robert Stallard, a New York-based analyst with RBC Capital Markets, said in a note. "Textron could really do with a recovery at Cessna."This report includes material from Bloomberg News.