Originally Posted by
Ovc000
To my knowledge the R44 Astro has a carburetor......and it surely was cold that day.....
Not saying the pilot didn't use full carburetor heat before descending but if he didn't, then on short final, the 'throttle valve' could have been partly blocked with ice, restricting fuel flow, the throttle will open more and more to desperately try to get more fuel flowing (hence why it's a good thing to keep your hands on the throttle so you can identify it if you missed it on the gauges).
All speculation of course but it is a rumour network.
The earlier R44 (Raven I) are all carburated, only the Raven II have fuel injections. Problem with the carburated ones is that the governor compensates carb ice until the throttle is fully open with no indication to the pilot except the turning of the throttle grip. Rpm and manifold pressure remain static until there is no throttle way left. Once the rpm drops, you are in deep trouble as the engine may not provide enough heat anymore to clear the manifold. We flew all carbed Robinsons with the
carb heat on when outside temp was below 15 degrees C. Fuel guzzling but safe.