RMAllnutt wrote:
It would make sense that the Hurricane would have a statement to that effect on the cockpit exterior by the way, as there were a number of cases during the war (and subsequently) where pilots were overcome by carbon monoxide fumes, passed out and died in the subsequent crashes.
I haven't been able to find a reference on a quick look, but the issue was
hypoxia, not carbon monoxide. IIRC, and the where and when is debatable, but I'm going to say Battle of Britain period, a number of Hurricanes and pilots were lost on rapid intercept scrambles - going from take off to oxygen-requiring height in as short time as possible, and under the stress of the scramble, turning on the oxygen was overlooked.
The stencil was common - perhaps mandated - for a brief wartime period, but was not seen commonly on Hurricanes; except (again I'm open to correction) in the latter period of the type's use as an interceptor. It was not seen pre-war, or Battle of France period, so post May 1940?
Carbon monoxide was a problem on some other types, particularly the Typhoon, where pilots were advised (ordered?) to wear a mask with oxygen on at all times.
Which leads to a modern warning. The Aircraft Restoration Co undertook some detailed carbon monoxide sampling on Spitfires a few years ago, and were very surprised (and concerned) to discover that pilots could easily ingest more than the recommended safe minimum of carbon monoxide
when taxiing with the canopy open! Certain other conditions, such as IIRC direction of the breeze or wind while doing so or similar were a factor, but everyone had assumed the carbon monoxide risk was at higher power (flight) with the canopy closed. The degree of incapacitation was not great, but would be a factor in an accident investigation - one that you'd rather not see. IIRC ARC circulated those details among the type operators, but it can't hurt for a new mention.
Regards,