DA42 LN-PFM down in Norway

I have not much clue that my instructor belief, but with a full stall speed of less than 60kt with 600fpm, i guess it would be a little more but not much as you have less incidence in a flat spin but outside wing is partially stalled.
Should we try? 😌

Emir wrote:

I believe reading Swedish case report is useful.

OK, I just have. I don’t know about Swedish or Norwegian twin training, but intentionally fully stalling a twin is considered suicidal round here and certainly NOT part of multi-engine training. However, a maneuver like this seems consistent with the decaying speed during the last phase of their flight.

with a full stall speed of less than 60kt with 600fpm, i guess it would be a little more but not much 

I don’t think L/D at stall VS is about 1:10 (best glide at Vbg is not published by Diamonds but I doubt it’s more than 1:10 in DA42? HK36 is 1:25 and DA20 is 1:12?), at stalls wing L/D is rarely beyond 1:5, in spins L/D in 1:2, in flat spins it’s near 1:0.1

There could be positions errors on ASI/VSI? KCAS on ASI and VSI slips

I don’t think L/D at stall VS is about 1:10

Why speculate on L/D etc etc when this plane obviously didn’t stall when doing -8000fpm?

There could be positions errors on ASI/VSI ?

??

I was not speculating, I was explaining why you can’t see -600fpm at 60kts in stall with DA42 (600fpm/60kts is 1:10)

Found the video – not a DA42 but shows what a flap spin looks like in a piston twin, and a DA42 won’t be any different

greg_mp wrote:

8600fpm descent reported by ADSB, this is not a flat spin for me. Either a suicidal pilot or loss of integrity, wing, fuselage… I discussed it with my CRI/CRE, and flatspin on a DA42 would be around 800fpm.

As I wrote, in the Swedish case of DA42 flar spin the average ROD was 9800 fpm. The final ROD just before impact was 3000-something fpm.

172driver wrote:

I don’t know about Swedish or Norwegian twin training, but intentionally fully stalling a twin is considered suicidal round here and certainly NOT part of multi-engine training.

That’s what everyone over here thought, too.

Thanks a lot for this report. Obviously I was talking about early spin, and these was fully developped and indeed this is frightening.
I would say that usally CRI doesn’t try this kind of fully developped stall spin. What is in this report:

According to the instructor, the exercise was conducted in the following
manner: The aeroplane was brought into a steep climb with an attitude of
approx. 25–30º at the same time as an approx. 30º bank to the right was set.
During the deceleration, both engines were set to full power and when the
aeroplane was approaching stall speed, the stick was pulled fully back.
However, the students gave evidence when interviewed that the pitch attitude
during the climb was at least 50º (nose up). This information also supports the
analyses conducted by the Swedish Accident Investigation Authority (SHK) on
data recorded by units in the aeroplane.

It’s non-sense and completely unsafe. Exercises in MEP training are far from these values and we are really watched when doing stall, so as to be ball-centered. Stall approach are done with safer pitch and roll, not with 50° nose high/ 30° bank/full power, especially with the natural high adverse yaw of the DA42, that you really have to overcome in handling exercises. I am surprised that flat spin initiated at 4500ft take that much vertical speed.

Why i’m doubting it’s a flat spin about the norvegian one, is the last series of ADSB samples:
391 2021-11-23 08:09:24 UTC 59.0828 9.8993 210° 3850 ft 140 kts -250 ft/min
392 2021-11-23 08:09:30 UTC 59.0790 9.8957 200° 3875 ft 130 kts 380 ft/min
393 2021-11-23 08:09:33 UTC 59.0772 9.8939 210° 3900 ft 130 kts 60 ft/min
394 2021-11-23 08:09:39 UTC 59.0742 9.8915 200° 3925 ft 110 kts 440 ft/min
395 2021-11-23 08:09:45 UTC 59.0713 9.8896 200° 3925 ft 90 kts -320 ft/min
396 2021-11-23 08:09:54 UTC 59.0681 9.8879 200° 3875 ft 70 kts -380 ft/min
397 2021-11-23 08:10:00 UTC 59.0664 9.8870 190° 3825 ft 70 kts -510 ft/min
398 2021-11-23 08:10:03 UTC 59.0652 9.8870 190° 3675 ft 40 kts
399 2021-11-23 08:10:09 UTC 59.0645 9.8874 190° 3050 ft 10 kts
400 2021-11-23 08:10:15 UTC 59.0640 9.8879 210° 2150 ft 10 kts -8700 ft/min
401 2021-11-23 08:10:18 UTC 59.0639 9.8882 210° 1675 ft 10 kts
402 2021-11-23 08:10:24 UTC 59.0638 9.8887 210° 975 ft 10 kts

With a bit of care about the accuracy of ADSB data, we can see that GS goes down to 70kn while heading keeps around 200°, even when falling.
It looks like a either a stall or a very vertical descent. If the heading is to be true, it may not be a spin. If not, then it would be more a spin after a stall. But we don’t see the altitude excursion that swedisch accident mention.