Half Moon Bay Accident - Cozy Mark IV

[FlyBoy66]

https://www.youtube.com/watch?v=AdcFhOdU-eQ

Another engine sputtering crash on take off where we will likely never know exactly what happened. The media will play this out like the reason for the crash was the fact the airplane is labeled 'Experimental' when the reality is that the engine, which is the cause of the crash, is well proven and certified in many airplanes. The 'Experimental' label here is completely irrelevant.

[FlyBoy66]

My opinion based on the known facts:

• They were clearly on a fun site-seeing flight as the pattern makes several circles over downtown San Francisco and the Golden Gate bridge, while making a full stop at Half Moon Bay for dinner. One possibility is that the pilot in command was distracted by company while become lax on the pre-check. Fuel selector could have been off or a sump check could have been neglected, etc.

• A sputtering engine is 99% a fuel or magneto issue so weight and balance can be ruled out.

• A bad magneto could cause this and the pilot may not have had enough time to go through the checklist given the low altitude.

• Water in the tank is highly possible, given all the rain. I'm not sure how the sumps are installed on the Cozy but on MANY airplanes sumping the tanks will VERY often not show water. On certain airplanes, like the Ercoupe, it would take over a pint of water for the sump to show water in the wing tanks because they have a bung inside the tank that sticks up about an inch. So even if the tanks were sumped there still could have been water in them.

I feel like the most probable cause is water in the tank.

I personally feel like MANY crashes happen and the FAA blames water in the sump while if you dig deeper you find the pilot claims the tanks were sumped. I use a large syringe on my airplane and have found water this way. Water that would have not shown up by the usual method.