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-   -   4th Aug 2018 Junkers JU52 crashed in Switzerland (https://www.pprune.org/accidents-close-calls/611836-4th-aug-2018-junkers-ju52-crashed-switzerland.html)

Teddy Robinson 5th Aug 2018 18:23

I was flying in the area yesterday.
ISA +17

Teddy Robinson 5th Aug 2018 18:37

Empty Weight 5.720 kg max. Takeoff Weight10.500 kg
Payload approx 2000 kg, so APS 7720 kg add fuel, add ISA +17, add mountain weather, add engine issue.
The investigators will deliver their report in due course, but in the meantime this a tragedy for 20 families.
Deepest condolences to those affected, this is terrible.

dadai 5th Aug 2018 18:59

The plane may have be carrying more weight than usual as this trip included an overnight stay and passengers will have taken luggage. The vast majority of Ju air flights are brief day sightseeing trips.

atakacs 5th Aug 2018 19:03


Originally Posted by Teddy Robinson (Post 10215386)
Empty Weight 5.720 kg max. Takeoff Weight10.500 kg
Payload approx 2000 kg, so APS 7720 kg add fuel, add ISA +17, add mountain weather, add engine issue.
The investigators will deliver their report in due course, but in the meantime this a tragedy for 20 families.
Deepest condolences to those affected, this is terrible.

Conditions might have been a bit on the edge of the performance envelope (although having flown a good half of the distance from Locarno the fuel load would have been relatively light) but that doesn't make the plane simply "drop off the sky" as reported by eyewitnesses. There is no indication of structural failure and even with an engine issue a force landing was certainly possible. Strange.

krohmie 5th Aug 2018 19:06

Anybody here with real information about the Power on stall characteristics of the Ju 52?






​​

atakacs 5th Aug 2018 19:11

Most likely unrelated to the accident but both pilots were in their 60s.

atakacs 5th Aug 2018 19:18


Originally Posted by krohmie (Post 10215412)
Anybody here with real information about the Power on stall characteristics of the Ju 52?
​​

I am sure that more competent people will chime in but my understanding is that with flaps up stall speed was about 65 and with flaps down lower than 55 knots

Double Back 5th Aug 2018 19:49

I was wondering the structural integrity till I just found this:
Its main spar was replaced recently as one source quoted but I could not verify this:
https://www.jetphotos.com/photo/8624142

markov 5th Aug 2018 20:05

BMW
 
Really tragic. I am acquainted with one of the engineers who donates his time to help service the engines on these aircraft. He tells me these are the only JU-52s still flying with the BMW 132 radial engines which were essentially reverse-engineered versions of an earlier P&W R-1690 Hornet design but with metric measurements throughout. All other JU-52s either shipped with P&Ws or were switched in later life, apparently due to ease of sourcing compatible parts. The engineers at Dübendorf laboriously and lovingly maintain these unique aircraft and apparently flight:maintenance hours ratio is well over 30. They are a common, beautiful sight all over eastern Switzerland and I hope this awful accident isn’t the end.

biscuit74 5th Aug 2018 20:41


Originally Posted by weatherdude (Post 10215283)
No, this is not the true. The max gust at Crap (Rock) Masegn at the time was a Max of 48 kph Hourly gusts in the area

Thanks Weatherdude. Apologies I meant to write 25 knots which is what the article said. Stumbly typing - tsk.
And of course, unless my arithmetic is daft, 48 kph is approximately 25 knots,.

Without lots of local knowledge & experience (which the crew evidently had) I'd be reluctant to fly a light wing loading aircraft immediately downwind of some impressive hills/mountains, especially one with large span and probably fairly poor roll authority by modern standards,. I'd imagine 'challenging' describes it well. As a sailplane pilot and tug pilot I have a lot of respect fro mountain & wave turbulence, I also have a lot of respect for the mountain flying skills of the people in the various Alpine countries.

Cheers,
Biscuit74

tractorpuller 5th Aug 2018 20:42


Originally Posted by Kerosene Kraut (Post 10215259)
The smoke statement came from Swiss TV.

Based on a comment by an "expert" who had seen the poor quality photo. There was no mention of this at the press conference, so I will wait for something more substantial.

Machinbird 5th Aug 2018 20:44

Stall ?
 
I would like to call attention to the picture originally linked by Kerosene Kraut (post 33). This was apparently a screen grab from a video. The "smoke" trail behind the aircraft lacks a focal point on the aircraft and an ominous explanation could be condensation in disturbed air behind the aircraft. I would post the picture, but this site is acting crazy.

updrifter 5th Aug 2018 20:58

The pic is posted on the Swiss state television SRF site. In the caption it says "One of the last pictures of the JU-52 at mountain Chamm in the Kanton Glarus".

DaveReidUK 5th Aug 2018 21:14


Originally Posted by Double Back (Post 10215454)
I was wondering the structural integrity till I just found this:
Its main spar was replaced recently as one source quoted but I could not verify this

While structural failure is one of many causes that can't be ruled out, a wing spar failure would be hard to reconcile with reports that the aircraft nosedived straight into the ground.

Tail feathers perhaps ...

EDLB 5th Aug 2018 21:21

With the plane still there without a post crash fire and likely some video coverage from passengers I will be surprised if they don‘t get a solid explanation in the upcoming weeks. There are lots of possible scenarios but why start guesswork when the evidence will come up soon.

gearlever 5th Aug 2018 21:26


Originally Posted by EDLB (Post 10215519)
With the plane still there without a post crash fire and likely some video coverage from passengers I will be surprised if they don‘t get a solid explanation in the upcoming weeks. There are lots of possible scenarios but why start guesswork when the evidence will come up soon.

Yep, IMHO some have already a very good idea what happened.

atakacs 5th Aug 2018 21:28

Whatever was trailing this aircraft, if anything, condensation would be extremely unlikely given the prevailing weather and the speeds involved.

weatherdude 5th Aug 2018 21:47

Condensation can be excluded...but maybe look at this
 
Just before crash time TCU only left very small gaps in the Segnas Pass area

Sat pic 1445 UTC, other times via menu

And just north of the pass, they already were at CB stage five minutes later

Radar crash time

To them, this must have looked like a closed curtain assuming there is no radar in front?

The main activity was north of the pass, I don't know what happens when you see close to the ridge that you have to choose which TCU or CB you want to fly into?



Originally Posted by atakacs (Post 10215526)
Whatever was trailing this aircraft, if anything, condensation would be extremely unlikely given the prevailing weather and the speeds involved.


atakacs 5th Aug 2018 22:03


Originally Posted by gearlever (Post 10215523)
Yep, IMHO some have already a very good idea what happened.

might be so but at the moment I am quite perplexed by this sad accident. I just don't see any scenario which would fit all known facts.

atakacs 5th Aug 2018 22:05


Originally Posted by weatherdude (Post 10215548)
The main activity was north of the pass, I don't know what happens when you see close the ridge that you have to choose which TCU or CB you want to fly into?

Interesting.
This might be the reason for the 180.
Still doesn't explain what seems to have been a fairly brutal stall.


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