WS3448 - Incident: Westjet Encore DH8D at Terrace on Sep 28th 2021

A Westjet Encore de Havilland Dash 8-400, registration C-GJWE performing flight WS-3448 from Terrace,BC to Vancouver,BC (Canada) with 10 passengers and 4 crew, was in the initial climb out of Terrace when the crew received a hot duct warning for both cockpit and cabin. The crew referred to the checklists for a single hot duct warning while continuing to climb. At FL240 the crew received a master caution for cabin altitude, donned their oxygen masks, declared emergency and initiated a rapid descent. The aircraft returned to Terrace for a safe landing.

The Canadian TSB reported maintenance replaced the compressor discharge overtemperature switch, checked the blow out panels and performed operational checks. A service difficulty report regarding the compressor discharge overtemperature switch was filed.

The Canadian TSB further annotated that the checklists did not contain any procedure for hot ducts warnings in both cockpit and cabin departments.