The article –
HERE – is well worth a read, particularly for Prop jet pilots in this neck of the woods, where the freezing level is often high with plenty of moisture (and mixing) when the cloud tops are just 'out of reach'. Boser, the editor has been fair though and mentioned other nasty icing incidents which have occurred with other types. Was it a SAAB ? at Bathurst? had a nasty go with ice one dark and stormy. I believe one of the most worthy elements of any PJ type rating is a look at the certification standard which define the various types of 'icing' and the protection required for flight in those icing conditions. The 'type' of icing, for which the aircraft is certified to operate in, may surprise some.
FAA
FAA
• Freezing rain (FZRA): Precipitation at the ground level or aloft in the form of liquid water drops. The raindrop diameters are greater than 0.5 mm. Freezing rain exists at air temperatures less than 0degC (supercooled), remains in liquid form, and freezes on contact with objects on the surface or airborne.
• Heavy icing: A descriptor used operationally by flight crews when they report encountered icing intensity to air traffic control. The rate of ice buildup requires maximum use of the ice-protection systems to minimize ice accretions on the airframe. A representative accretion rate for reference purposes is more than 3 inches (7.5 cm) per hour on the outer wing. A pilot encountering such conditions should consider immediate exit from the conditions.
• Light icing: A descriptor used operationally by flight crews when they report encountered icing intensity to traffic control. The rate of ice buildup requires occasional cycling of manual deicing systems to minimize ice accretions on the airframe. A representative accretion rate for reference purposes is 1/4 inch to one inch (0.6 to 2.5 cm) per hour on the outer wing. The pilot should consider exiting the condition.
• Moderate icing: A descriptor used operationally by flight crews to report encountered icing intensity to traffic control. The rate of ice buildup requires frequent cycling of manual deicing systems to minimize ice accretions on the airframe. A representative accretion rate for reference purposes is 1 to 3 inches (2.5 to 7.5 cm) per hour on the outer wing. The pilot should consider exiting the condition as soon as possible.
• Severe icing: A descriptor used operationally by flight crews reporting encountered icing intensity to traffic control. The rate of ice buildup results in the inability of the ice protection systems to remove the buildup of ice satisfactorily. Also, ice builds up in locations not normally prone to icing, such as areas aft of protected surfaces and any other areas identified by the manufacturer. Immediate exit from the condition is necessary.
While acknowledging the 'ice' problems, we digress. As far as anyone knows, this incident was structural and unless the chook they allegedly hit was frozen solid, still in the bag, then icing has little to do with the event being considered.
Anyone know if the ATSB have broken cover yet on this event? they are overdue.