** Shares of aircraft parts supplier Howmet Aerospace HWM.N fall 7.6% to $102.01 premarket

** HWM may halt some shipments if they are impacted by tariffs announced by U.S. President Donald Trump, according to a letter seen by Reuters

** Company, which supplies parts for planes built by Airbus AIR.PA and Boeing BA.N, has declared a force majeure event — a legal practice that allows parties to a contract to avoid their obligations if hit by unavoidable and unpredictable external circumstances, it says in a letter to customers

** "Given how globally integrated the supply chain is, we see tariffs as adding an extra layer of complexity in an already difficult industrial re-ramp, at least for H1," Jefferies analysts say in a note

** "With tariffs also weighing on the economy, risks of recession could hurt overall aircraft demand and air traffic, hence aftermarket" - Jefferies

** As of last close, HWM shares up 2.7% YTD

(Reporting by Aatreyee Dasgupta)

((Aatreyee.Dasgupta@thomsonreuters.com))