The Transportation Safety Board (TSB) of Canada issued a final recommendations on July 4, identifying aircraft required to have either a Class A or a Class B version of a terrain alert and warning system (TAWS) installed. TAWS is an updated version of a ground proximity warning system (GPWS) and is based on more predictive rather than reactive data from GPWS.
The new rules, outlined in Canadian Air Regulations subparts 605, 703, 704 and 705, apply to nearly all-commercial air taxi and airline operators, as well as to those operating private turbine-powered aircraft with six or more passenger seats. The only exception for private turbine-powered aircraft is for those operating under daylight VFR conditions.
The rules became effective immediately for all aircraft manufactured after the July 4 date. Aircraft built prior to July 4, 2012 have two years to install equipment that meets the new Canadian standard.
The new recommended standard was developed after 35 separate controlled flight into terrain (CFIT) accidents between 1977 and 2009, which altogether claimed 100 lives. The new TAWS systems must include the enhanced altitude accuracy (EAA) function. TAWS includes a forward-looking terrain display and calculates a terrain clearance floor based upon calculated distance to a specific runway threshold. Clearance floor alerts are also independent of the position of the aircraft’s landing gear or flaps.