Proper single engine shut down / restart in flight

[RichardD_flyNEXA]

Hi - am a CFI/CFII/MEI out of AZ and have been flying the DA42 for my multi students - still transitioning a bit and ran into the AD pertaining to windmilling the eng (not to do it) - and for any start/restarts, one is to use starter after proper shut down....we are now actually replacing timing belt on the engs that did windmill...

But - the real question is will htis be fixed in future? and, i'd love to hear from other MEIs & even factory instructors on the work around to then still enable SEO training....

[Chris]

But - the real question is will htis be fixed in future? and, i'd love to hear from other MEIs & even factory instructors on the work around to then still enable SEO training....

I haven't heard of any changes in progress to allow windmilling restarts for Austro engines.

My reading of the AD is that you simply can not use windmilling restarts except in an emergency. When I was training in a DA42NG, we would slow the plane down enough to keep the prop from windmilling before re-activaing the engine master, and ensure that the prop was stationary before activating the starter. I don't recall the exact airspeed we used for that, but I believe it was around 90 KIAS.

There are some other threads on here about this. Here's one of CFIDave's posts on the subject.

[MikeMeadows]

Hi - am a CFI/CFII/MEI out of AZ and have been flying the DA42 for my multi students - still transitioning a bit and ran into the AD pertaining to windmilling the eng (not to do it) - and for any start/restarts, one is to use starter after proper shut down....we are now actually replacing timing belt on the engs that did windmill...

But - the real question is will htis be fixed in future? and, i'd love to hear from other MEIs & even factory instructors on the work around to then still enable SEO training....

Guidance I was given, and that which I give:
Restart airspeed of 80 - 85 KIAS with the propeller in the static position at the moment the starter is engaged. The propeller may rotate slightly at 85 KIAS but will pause to allow starter engagement. If for some reason the propeller is not pausing, the airspeed can be further reduced to 80 KIAS where it should stop rotating completely. Use 85 KIAS since it is the blue line speed and below 90 KIAS were the propeller pause may be minimal. A starter engagement should never be attempted if above 90 KIAS with the ideal speed of 80-85 KIAS.

**Do not engage the starter when the propeller is wind milling.

1. POWER lever of affected engine ........................IDLE
2. FUEL SELECTOR of affected engine...................check ON
3. Alternate air ...........................................................as required
4. ALTERNATOR of affected engine .......................On
5. ENGINE MASTER of affected engine..........On, propeller un-feathers
6. STARTER of affected engine................... engage when propeller is stationary

Mike Meadows
Houston, TX
ATP Single & Multi, CFI CFII MEI

[mfdutra]

If you have enough height, as you should in training, pull the operating engine back to 12-15%, so you don't have to deal with yaw and the risk of losing directional control. Let the airplane descend gently while maintaining 80 knots.

[ememic99]

If you have enough height, as you should in training, pull the operating engine back to 12-15%, so you don't have to deal with yaw and the risk of losing directional control. Let the airplane descend gently while maintaining 80 knots.

That’s really slow and uncomfortable for clean configuration and single engine operation. I wouldn’t feel comfortable with 80 knots.

[RichardD_flyNEXA]

Great feedback on this post - def aware of this and incorporated into our training, steps to avoid unnecessary windmilling - i am ever more curious as to the longer term "fix" as it were - any ideas on hte root issue (am a bit in weeds here) - but if the issue of windmilling, specifically, causes "stress" on timing chain - how does it do that and why doesn't electric start cause same issue? - is there an eng design improvemetn in future to alleviate this issue given the prop can, actually, windmill start BUT it affects teh timing chain and should only be used in emergencies and NOT for training or unnecessary reasons...i'd love to hear from design engineers at Diamond on plans to fix this systemically...

[ememic99]

but if the issue of windmilling, specifically, causes "stress" on timing chain - how does it do that and why doesn't electric start cause same issue?

I'm also puzzled with this but since I don't fly the aircraft with Austro Engine I didn't invest much effort in researching the topic. However, CD-135/155 (Thielert) is very similar engine, yet it doesn't suffer from this issue.

[mfdutra]

That’s really slow and uncomfortable for clean configuration and single engine operation. I wouldn’t feel comfortable with 80 knots.

On the DA62, that's the required speed for a restart in flight.

If you have the good engine at 12% and the other engine feathered, you aren't really "single engine". You're just a glider.

[ememic99]

That’s really slow and uncomfortable for clean configuration and single engine operation. I wouldn’t feel comfortable with 80 knots.

On the DA62, that's the required speed for a restart in flight.

If you have the good engine at 12% and the other engine feathered, you aren't really "single engine". You're just a glider.

My glider days were 30 years ago

[nickname]

From personal experience I have seen restart speeds cited of 90-100 KIAS, but I have seen windmilling just above, ie 93-95 KIAS. I now try to target 90 or slightly over and don't have any issues.