Helicopter Ground-Runs Performed by Engineers/Mechanics
The recent AS350 accident in Brazil where the helicopter was destroyed on the ground by severe vibrations after landing brings to mind the perennial question of helicopter engine ground-runs being performed by engineers/mechanics. I had expected the thread on this accident to drift into this topic, but it seems to have faded away first.
When the question is asked, the most common and instant reply is "it isn't allowed", but when you ask for the authority of this reply you usually get a deafening slience or "we never do it". The next most common reply is "what if you get into ground resonance, you can't take-off to correct it".
Let's clear up the first reply, "it isn't allowed". Generally, only two parties can say this with total authority; a) the helicopter owner and, b) the helicopter insurerer, both for quite obvious reasons.
I only know of one country where legislation specifcally requires helicopter engine ground-runs to be performed by an approriately rated pilot.
In my previous company, nominated senior engineers/mechanics were trained and authorised to perform engine ground-runs, with limitations of course (no raising the collective etc.) and this was a boon to the end-of-day routine when engine washes and/or minor maintenace was required and there was no lengthy waiting for a pilot. The pilots were happy and the engineers/mechanics were happy.
I wonder, how many other helicopter operators out there allow engineers/mechanics to perform helicopter engine ground-runs. How is this administered and what are the limitations etc.?