337 Video
 

Now he needs to figure out why the doors are open with the gear down

If you read the comments on You Tube and Facebook you will see that they answered the mystery

They pumped the doors open during the preflight and video work and then just forgot they were open.......

That would require common sense and casual observation, skills I have limited grasp upon. However, why didn't the gear doors close when the engine was started?

Dave

Not sure you totally understand the system, but maybe you are confusing the original 337 hydraulic system with the later electric over hydraulic system.

Original system is an engine driven hydraulic pump that is actuated by a linkage moved by the gear handle on the panel. When the engines are started the pump is ready to work but the handle on the panel has to be operated to allow the system to operate.

Newer electric system used an electric motor to run the hydraulic pump. The gear switch on the panel was just a mouse click with no actual linkage connected to the system. When the master switch was turned on the pump was primed and ready. If there were micro switches on the gear that were not closed the pump would actuate to close the system.

This 337 in the video was an older system with gear pumps on the engines. If you used the hand emergency pump handle to open the gear doors for inspection during pre-flight, then the doors would not move back close unless you turned on the master switch and pumped the E handle or once the engines are started you could select the gear handle down and it would close the doors on the ground.