Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 240; Flight Crew Total 20000; Flight Crew Type 1800
ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Flight Crew Requested ATC Assistance / Clarification
Chart Or Publication; Human Factors; Procedure
During our descent; we were cleared direct ROKTO and a descent to 11;000 FT. As we passed ROKTO at 13;800 FT ATC called and said there was an altitude restriction at ROKTO between 16;000 FT and 14;000 FT. We were initially filed for the YWT4 arrival to CYYZ; but had not been cleared for the arrival. We assumed our descent clearance was a stand alone clearance to 11;000 FT and not part of the arrival; and since we weren't cleared to 'descend via' we thought we were fine. Toronto Center advised us that Canadian procedures do not use [the 'descend via' phrase]. He further stated that it was no problem as there was no other traffic in the area. We then accomplished a normal descent; approach; and landing to Runway 24L. We had pre-briefed the altitude restrictions and compliance prior to top of descent; but the clearance below the first restriction coupled with not being verbally cleared for the arrival lulled us into this mistake.
After we started [our descent]; we received a clearance to descend to 11;000 FT. There was no 'descend via the arrival' of a descent to 11;000 FT and comply with crossing restrictions; just a standard descent. We asked why we were not cleared to descend via the ROKTO and they said they did not give clearances like that to prevent confusion. This is exactly the opposite of US ATC procedures and creates massive confusion especially when you rarely fly to Canada!
When cleared by Toronto Center to descend to 11;000 MSL on their cleared route the US based flight crew was unaware the clearance required them to meet the crossing restrictions on their filed arrival. As a result they crossed ROKTO 100 feet low.