You misunderstand me, but no worries. I've been flying commercially for a quite a while now in challenging environments.

The copy of the company manual I have seen (for the company involved in the accident) says you can't exit a running helicopter unless its for a pilot swap or done with a control hold, which is undefined, hence my first question.

Knowing the pilot involved personally and knowing both his method of flying and how he operated I can't see him ever doing something that violated the ops specs, unless the company told him to do one thing in the ops spec but then trained him to do another out on the line.

So I'm trying to understand the why.

No harm done and no worries.

There are many things in aviation and life in general that we struggle to understand. Sometimes it is just best to face West, drink a shot in their name, learn from what happened and move forward. The biggest dis-service we can do for a fellow aviator who died is to not learn something.

Fly smart & abide.......

Unfortunately turning off the hydraulics is a flawed assumption as a few people have found out.

I note that a few condone the action on this thread.

Take a look at the "irreversible" function and how it works on some common models.

You may find that you are better off with HYD ON and friction ON.

Many years ago company policy for leaving the aircraft unattended was to NOT turn HYD OFF as they had found out the
hard way on more than one occasion!

Bull$hit and assumption will only get you so far!

RVDT speaks correctly.

Leave the Hydraulics ON...that is the standard mode that it was designed to use at all times.

Lots of Friction and a Control Lock if fitted is the right way.

Hydraulics off, the controls can overcome even the tightest friction in some cases. Some aircraft are totally uncontrollable without hydraulics, and thus are required to have two independent systems. Some have only one system, but are only marginally controllable without it. The only time I would turn the hydraulics off in any helicopter would be for required checks or training. I've done hydraulics off landings in the AS350, but it's a handful, and you have to stay on top of it. Give it a minute or two without any intervention, and bad things may happen. With the hydraulics working and the friction tight, nothing should move. But I still wouldn't risk exiting with the engine running unless it was really, really necessary.