THE US FEDERAL Aviation Administration is to examine how a range of turboprop airliners behaves in icing conditions, following its new directives relating to the ATR 42 and 72 (Flight International, 18-24 January).

Extensive testing of ATR aircraft in the wake of the fatal crash of an American Eagle ATR 72 in Roselawn, Indiana, on 31 October, 1994, show that they comply with icing-certification regulations.

An abnormal icing condition not covered by any certification requirement may have occurred, however, and the FAA wants to see if overall icing-certification criteria should be toughened.

FAA associate administrator for regulation and certification Tony Broderick says: "This is the first time these types of extensive testing for icing problems have ever been done. We feel it's necessary to put all similar aircraft to the test. If more defects are found, we will change our certification rules accordingly."

ATR president and chief executive Henri-Paul Puel says: "In a field so poorly understood, these tests will produce an evolution of the existing certification rules."

The company earlier claimed that it reproduced the aileron-lock problem which worried the FAA on three other twin-turboprops. The data, on the Saab 340, Fokker 50 and Embraer EMB-120 Brasilia, have been provided to the FAA.

FAA administrator David Hinson says: "There have been no problems with icing on any other turboprops that we are aware of. There have been no reports, incidents or accidents caused by icing. But as a matter of course, when we are finished with the ATR issue, we will look at the same sort of issue for other turboprops. That just makes sense."

Source: Flight International