PB4

anyone has more information about the cause of the DA42 that crashed in woods last week outside Stockholm ?
Media were suggesting pilots reported engine trouble to the tower before crashing, also anyone has info on the condition of the occupants ? again media were reporting they were taken to hospital in 'unknown condition'.. hope everyone is alright.
Am interested only because I did my training on the DA42 and this ac had other engine troubles in the past.

Founder

It seams that one of the engines feathered during climb and with 4 male persons onboard I guess it was too heavy to stay airborne.

There were similar problems with a DA42 that I flew. During go-around the engine feathered a number of times and it seamd to be a software problem but I dont know if it was resolved or not.

The occupants seamed to have managed okey except for one which 2 days after the accident was still in a critical condition.

bad_attitude

i've done a bit of time on the 42 as well ... in one of the a/c's we had, the pin which prevents the prop from feathering just sheared off ...

but the prop shouldn't feather in flight ... doesn't make sence, higher the oil pressue, the finer it becomes ... the only reason it would probably feather is if the throttle were at idle and the locking pin sheared off or something ...

wish a speedy recovery to all those involved.

PB4

diged into my pdf's for the DA42, here is what I found on feathering:

Feathering System
- No „Auto-feather“
- Feathering by „Engine Master OFF“ if RPM above 1300
- If RPM below 1300: prop pitch remains above high pitch lock
- Unfeathering by oil pressure from accumulator when Engine Master is ON


Never had any problems in the aircraft myself though, hope all involved will recover quickly.

bad_attitude

any further information on the crash?

CirrusF

If they were below the certified MTOW (1785kg), then with critical engine failure, if they followed the procedures properly, the aircraft would still climb at about 180ft/min at blue-line.

I would hazard a guess that they were either overweight (with 4 male pax they would have had to have had very little fuel to stay under the MTOW), or else they did not follow the engine failure procedures properly.

Possibly they tried to restart the engine after turning off the master-switch - this is very dangerous and I know of another DA42 that crashed because the pilot made this mistake. If you turn off the master-switch after an engine failure, the prop will feather to minimise drag and you can climb at about 180ft/min at MTOW on single engine. However, if after climbing to a perceived safe height, the pilot decides to restart the engine by turning on the master switch, the oil pressure in the accumulator will be released and a spring will move the prop back to fine pitch. If the engine does then restart, then all is well. However, if it does not start, there is no more pressure in the accumulator to feather the prop. So you will be stuck with a windmilling prop in fine pitch. With that much drag, you will go down.