[Graham Boak]

I think this may be more a factor of the operational use rather than the Sunderland itself. How many successful bale-outs were achieved from Coastal Command Catalinas, Halifaxes or Liberators? Operating at low-level, as Sunderlands did generally, particularly if attacked by fighters, would make baling out unlikely to succeed. As far as factors specific to the type are concerned, the enclosed flight deck would make it difficult for the crew working their to escape, but this is common to almost all transport/multi types. Other internal positions would have access to the side doors - like all flying boats, the Sunderland lacked escape hatches on the floor such as in the Halifax.

However RAF rear turrets could be swung to the side letting the gunner fall/bale out of the opened rear doors, and I don't know why that would be different on the Sunderland. This could be more a matter of how the gunner kept his parachute.