The mention of Viscount and fire brings to mind Viscount VH-RMI, in cruise at FL175 reported "on emergency descent" with fire warnings on both #1 and #2 engines, one was "out" and they were unable to feather the other engine (#2). Caused by the break up of the rotor in the No. 2 cabin pressurisation blower, which then ignited the lubricating oil. Airflow through the wing caused a breach in the No. 2 fuel tank and the fuel fed fire was directed by airflow to the spar upper boom. At 4,000' on descent to the airport the wing failed. 24 died. Entire process encompassed 15 minutes.