11.   Three other models were tested by having aerial tankers pray their wings with water as they flew in formation at high altitude to simulate icing conditions.

12.   Turboprops tend to fly more at the altitudes prone to icing conditions, and turboprops are increasingly popular.

13.   ATR chief engineer Andre Bord testified that European certification requirements for the plane to operate in icing conditions are more stringent and U.S. standards should be tightened.

14.   ATR officials said in a release that prolonged holding in observed icing conditions should have constituted a critical phase of flight.

15.   ATR said its turboprop planes already exceed Federal Aviation Administration standards for safety in icing conditions by a factor of four.

16.   Hinson has been evaluating the results of extensive flight tests of the planes in icing conditions, conducted at Edwards Air Force Base in California.

17.   The U.S. government, spurred by a deadly October crash in the state of Indiana, banned use of ATR turboprop aircraft when icing conditions are present or predicted.

18.   ATRs have recently come under scrutiny for the potential to crash in icing conditions.