Hawker Typhoon modification 293

[Trilisser]

What does mod. 293 include in detail? According to the Typhoon Pilot's Notes, unless mod. 293 is incorporated, oxygen mask must be worn at all times.

 

[Wurger]

The mod 293 was introduced in order to limit the seepage of carbon monoxide fumes into the cockpit. This was the reason the oxygen mask had be used at all times as a protection against carbon monoxide poisoning. Therefore the longer exhaust stubs were fitted in November 1941. Despite the modifications, the problem was never entirely solved, and the standard procedure throughout the war was for Typhoon pilots to use oxygen from engine start-up to engine shut down. In addition to carbon monoxide seepage, pilots were experiencing unpleasantly high cockpit temperatures, eventually a ventilation tube helped alleviate, but did not solve the problem. In addition two small, rear opening vents were added below the port side radio hatch, just below the canopy. Also at the same time the left ( portside ) cockpit doors were sealed.

the info ... Hawker Typhoon - Wikipedia

 

[Trilisser]

According to the Typhoon Pilot's Notes, oxygen mask was not needed to be worn at all times with Mod. 293 while without it the PN says it must be worn.