Melbourne King Air Crash - Rudder trim set incorrectly

Gruesome!

I can’t even fathom why the rudder trim would end up left in such a setting.

Neil wrote:

I can’t even fathom why the rudder trim would end up left in such a setting.

I fear I can.

I can’t speak for the King Air, but on the PA31 rudder trim position is detected and reported to the cockpit electrically.

On one occasion, I noticed that after some unrelated maintenance, when I did my after start checks the rudder trim indicator was hard over. I was able to adjust it to the middle from the cockpit, but luckily it occurred to me that I would have noticed on walkround if the trim tab were hard over.

So I shut down, got out and visually inspected the trim tab, which was now hard over to one side (with the cockpit indicator showing neutral.)

It transpired that the sender had been disturbed in the unrelated maintenance (which had been in the tail cone area) and was later found to be faulty, or out of adjustment.

I can easily believe that if I (or anyone) had been pressed for time – say an IFR slot – I might have thought “oh those scatterbrained grease monkeys! Leaving the rudder trim so far out of alignment , I’ll have a word with the little tykes when I get back!”, set to the apparent middle and taken off.

Would this create some unusual taxiing behaviour via the rudder/nosewheel linkage (which I realise may well not be present in all aircraft types) ?

Is this amount of rudder trim authority unique to twins? (Just thinking about where I left the rudder trim in the PA-28!).

Timothy wrote:

I fear I can.
I can’t speak for the King Air, but on the PA31 rudder trim position is detected and reported to the cockpit electrically.
On one occasion, I noticed that after some unrelated maintenance, when I did my after start checks the rudder trim indicator was hard over. I was able to adjust it to the middle from the cockpit, but luckily it occurred to me that I would have noticed on walkround if the trim tab were hard over.
So I shut down, got out and visually inspected the trim tab, which was now hard over to one side (with the cockpit indicator showing neutral.)
It transpired that the sender had been disturbed in the unrelated maintenance (which had been in the tail cone area) and was later found to be faulty, or out of adjustment.

OK maintenance is one reason I had not considered; Surely the report would have said if it was straight out of the maintenance workshop? If our aircraft are fresh out of maintenance we always spend a good few minutes more checking the position of every switch etc. However, given that this aircraft crashed I think the position of the trim knob on the pedestal would be how the investigators got to their conclusion, so it sounds unlikely that it was that the indication was mismatched to the actual trim tab.

denopa wrote:

Would this create some unusual taxiing behaviour via the rudder/nosewheel linkage (which I realise may well not be present in all aircraft types) ?

As far as I’m aware the position of rudder trim is not apparent when taxiing on a King Air

Aveling wrote:

Is this amount of rudder trim authority unique to twins? (Just thinking about where I left the rudder trim in the PA-28!)

Because the engines are powerful so is the rudder trim on a King Air 200. They are a handful asymmetric until the prop is feathered, and this is why autofeather is a no-go item on later models with 4 blade propellers