4th Aug 2018 Junkers JU52 crashed in Switzerland

[skadi]

A historic Junkers JU52 crashed today in the Swiss Alps.

JU 52 (http://avherald.com/h?article=4bbf2069&opt=0)

skadi

[BluSdUp]

It is great to have these old birds flying instead of hanging in a museum collecting dust.
Sad to see one go.
I admire the dedicated enthusiasts that visit air shows with them.
RIP

[Chris Scott]

Interesting that the wreckage as pictured is on an area of flat, relatively horizontal ground - rather than on an adjacent mountain slope. Could it be a forced-landing attempt?

[Machinbird]

Could it be a forced-landing attempt?
I don't think so. This was a relatively high energy impact that caused the fuselage to fail under linear compression in several locations.
More likely something like stall-spin, pilot incapacity, control problems, or structural failure.
Not a pretty picture at all.
RIP

[BEA 71]

https://cimg2.ibsrv.net/gimg/www.gmforum.com-vbulletin/1920x1440/haar_7_jul_18_102__0e94b54b28b9663ac8c19121e5bcdb135fab7372. jpg
https://cimg3.ibsrv.net/gimg/www.gmforum.com-vbulletin/1920x1440/haar_8_jul_18_51__022127235d5e3412b05ee6fdce7bca353836448d.j pg

This is very sad. Have seen the bird quite frequently, when heading for the Tegernsee area from Oberschleissheim airfield
or coming back. They were usually flying along the A 99 Highway. My sincere condolences to all affected.

[Airbubba]

This is very sad. Have seen the bird quite frequently, when heading for the Tegernsee area from Oberschleissheim airfield
or coming back. They were usually flying along the A 99 Highway. My sincere condolences to all affected.

Sad indeed but I believe your photos are of the sister Ju52 HB-HOP, not the accident aircraft.

[1sky]

Apparently 20 dead incl. three crew.

[krohmie]

New cable in the vicinity:
From Avherald

Just came across the following NOTAM with a warning about a cable in that area. Might it be possible that they fly so low?

B0866/18: Obstacle erected
Q) LSAS/QOBCE/V/M/E/000/074/4653N00914E005 ROPEWAY CABLE 1.7KM SSE SEGNASP. MARKED, LGTD, LEN 699M, 465238N0091407E, 100.0M / 328.1FT AGL, 2251.0M / 7385.0FT AMSL.

FROM: 03 Aug 2018 05:51 GMT (07:51 CEST) TO: 07 Sep 2018 23:59 GMT (08 Sep 01:59 CEST)

[Airbubba]

As always, gotta love the crypto exercise trying to read a NOTAM in 1930's teleprinter format. :ugh:

However, if my decoder ring is correct, the location is only two miles from the Piz Segnas crash site :eek::

https://cimg5.ibsrv.net/gimg/www.gmforum.com-vbulletin/2000x712/cable_notam_47b5a6f7976d01ae38f7cc104f7057630c5b1b40.jpg

[AN2 Driver]

However, if my decoder ring is correct, the location is only two miles from the Piz Segnas crash site :eek::


Yes and while this does not make it a smoking gun just yet, it's the first piece of information which has popped up which makes me wonder if it has anything to do with this. Those pilots REALLY know that area, there is not much which would surprise them to the extent that they might loose the airplane. And they are VERY experienced and proficient. However, a cable at a position where they did not expect it, yea, that would do it.

[BEA 71]

Sad indeed but I believe your photos are of the sister Ju52 HB-HOP, not the accident aircraft.

I was aware of this, Airbubba, there is some conflicting Information regarding the registration. This is HB-HOP, seen on 7th and 8th July.

[glad rag]

"Yes and while this does not make it a smoking gun just yet, it's the first piece of information which has popped up which makes me wonder if it has anything to do with this. Those pilots REALLY know that area, there is not much which would surprise them to the extent that they might loose the airplane. And they are VERY experienced and proficient. However, a cable at a position where they did not expect it, yea, that would do it.

Cable
By Peter on Saturday, Aug 4th 2018 22:10Z


According to the Notam the cable is at 2251mASML and the crash site accoring to the police statement is at 2540mASML.

Assuming these facts are correct, it seems unlikly that the cable is related to the accident. After impacting a cable the aircraft would not climb another 290m."

Ref.. Crash: Ju-Air JU52 at Piz Segnas on Aug 4th 2018, impacted terrain (http://avherald.com/h?article=4bbf2069&opt=0)

RIP. Condolences to all involved or affected.

[RenegadeMan]

https://cimg6.ibsrv.net/gimg/www.gmforum.com-vbulletin/1419x814/hb_hot_e1a3a5519a84c18264400f10a5d55be8fd4ae1ff.jpg

[OvertHawk]

Very sad event, and condolences to all involved.
The recent presence of a cable in the area does concern. I can imagine that it might be involved in the accident, despite the reported differences in elevation. However, I am sure this accident will be fully investigated and the facts revealed. RIP

OAP

There is a comment after the AvHerald article (In the OP) that purports to be from one of the team working on the cable in question stating that they heard the crash distant from their location and that their cable was not involved.

Quote " As one of the installers of the cable mentioned in this report i can ensure you, that the incident is unrelated. We watched the plane fly by high above us and heard the crash loud and clear. The cable was not installed at the time of the incident" End quote.

Ok it's only a post on a forum but it's worth considering - Why lie? If their cable was involved then the evidence will demonstrate it.

A very sad event indeed.

OH

[EDLB]

Important for the other Vintage birds will be the reason for this accident. Fortunately the fuselage did not burn down complete, so there will hopefully be video coverage from inside left. Most times those mountain crashes are in IMC or night conditions but this one was in VMC and the bird could have done a emergency landing on the slope with minor damage if there where no additional holes in the cheese.

[dadai]

They may have been trying to get a look through the famous Martinsloch rock window. The flight was a special excursion from Zurich to Locarno with an overnight stop and meal there. They were on their way back. It looks like it was one of the highlights of the excursion programme for the company for this year from the details on their website. A tragic event.

[atakacs]

Important for the other Vintage birds will be the reason for this accident. Fortunately the fuselage did not burn down complete, so there will hopefully be video coverage from inside left. Most times those mountain crashes are in IMC or night conditions but this one was in VMC and the bird could have done a emergency landing on the slope with minor damage if there where no additional holes in the cheese.
Agreed - Obviously too early to have all the facts but this one is a bit baffling: the terrain they end up on was indeed favourable to an emergency landing, and with this type of aircraft it would be quite feasible. Conditions were perfect and there is no indication of major failure,
There will be a press conference this afternoon with hopefully more information but the death tool seem to be 20.
Very sad.

[Toryu]

The picture we're seeing on avherald has been shot with a telelens and only shows a narrow section of the surroundings. I'd say it's shot about 20 degrees downslope and thus gives the illusion of relatively flat terrain.

The german Wiki-article shows this picture of the crash-area landscape:
h ttps://de.wikipedia.org/wiki/Absturz_einer_Junkers_Ju_52_2018#/media/File:MartinslochBoden_040.jpg
The crash-site would be between left of the two distinctive boulders in the center/ center-left of the picture.

They would have been flying upslope (to the right) this valley, probably trying to get over the pass:
h ttps://de.wikipedia.org/wiki/Segnaspass#/media/File:Unt._Segnasboden_in_richtung_Ofen,_Tschingelh%C3%B6rner ,_Segnaspass.jpg

Note: Since I can't post direct URLs now, you'll have to go the hard way, copy the links into your browser and edit-out the space between "h" and the rest of the link.

Can anybody confirm (or deny) this routing?

[Raffles S.A.]

From the picture on Avherald, the plane looks like it crashed inverted.

[skadi]

An eyewhitness at the nearby Segnas-Hut saw the JU approaching from the south, making a 180° turn and fell straight down...

skadi

[ORAC]

A later comment from the site linked in the original post.

“Cable/Rope and NOTAM
By (anonymous) on Sunday, Aug 5th 2018 07:55Z

As one of the installers of the cable mentioned in this report i can ensure you, that the incident is unrelated. We watched the plane fly by high above us and heard the crash loud and clear. The cable was not installed at the time of the incident. Regards”

[HarryMann]

Ohhh.. So tragic. Tried to book a flight on one of Lufthansas Ju52s 3 years ago.
180° turn away from rising ground ? Possible adverse gradient wind... Large span aircraft at low speed. Not unlikely inner tip stalled :(

[atakacs]

I'm really wondering about that 180. If they actually completed it (it would seem so) a subsequent stall is somewhat odd...
I guess there was no flight recorder of any type fitted. As mentioned by others on board shots are a distinct possibility.

[Alpine Flyer]

Swiss police confirms all 20 on board are dead.
RIP. A sad day for historical aviation.

[Alanwsg]

Just posted on the BBC & Sky news ....

https://www.bbc.co.uk/news/world-europe-45076060

https://news.sky.com/story/all-20-people-aboard-world-war-two-plane-die-after-crash-in-swiss-alps-11462086

[Kerosene Kraut]

https://ibb.co/h0T83z

Looks like trailing smoke or fuel behind the right hand engine. Attitude looks almost stalled?

[Onceapilot]

Reported online by BBC,
"Based on the situation at the crash site we can say that the aircraft smashed into ground almost vertically at relatively high speed," said Daniel Knecht of the Swiss Transportation Safety Investigation Board.

"What we can rule out at this point is that there had been a collision before the crash, neither with another aircraft nor with some other obstacle such as a cable."

Again, very sad to have the loss of life confirmed.

OAP

[Rob Bamber]

From the BBC and Sky's photos, there was no fire, and it looks like the 3 engines have buried themselves in the soft ground: vertical impact.

Very sad. RIP.

[Kerosene Kraut]

Pretty respectable Avherald has the right pictures. What do you mean by wrong crash?
Crash: Ju-Air JU52 at Piz Segnas on Aug 4th 2018, impacted terrain (http://avherald.com/h?article=4bbf2069&opt=0)

[arketip]

https://cimg5.ibsrv.net/gimg/www.gmforum.com-vbulletin/990x743/xl_gi3u_66b7ae163403b72fa9d7481abb5941b6a6330a23.jpg

https://cimg8.ibsrv.net/gimg/www.gmforum.com-vbulletin/990x743/xl_gi3v_95333d3d4f879148fca55e049fa264a2fa7b2373.jpg

[tractorpuller]

https://ibb.co/h0T83z

Looks like trailing smoke or fuel behind the right hand engine. Attitude looks almost stalled?
Looks like the mountain in the background. I see no smoke.

[Kerosene Kraut]

The smoke statement came from Swiss TV.

[biscuit74]

I see the Avherald report notes a local weather station stating winds were from the North gusting up to 35 knots. Looking at the map provided in the same article showing the police indication of the crash site location, I'd imagine strong potential for lots of curl over, turbulence and downdraft in that area - though that would be something two experienced Swiss pilots would be very well aware of.

A very great shame & tragedy for those involved. The Tante Ju is an iconic aircraft of distinctive looks and sound.

[weatherdude]

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 (https://kachelmannwetter.com/ch/messwerte/glarus/windboeen/20180804-1500z.html)



I see the Avherald report notes a local weather station stating winds were from the North gusting up to 35 knots. Looking at the map provided in the same article showing the police indication of the crash site location, I'd imagine strong potential for lots of curl over, turbulence and downdraft in that area - though that would be something two experienced Swiss pilots would be very well aware of.

A very great shame & tragedy for those involved. The Tante Ju is an iconic aircraft of distinctive looks and sound.

[HarryMann]

A wind of even 35kph could still create a significant rotor effect downwind of a hole, slot or sharp ridge...

[Onceapilot]

The description of "almost vertical, at relatively high speed" seems very broad brush at such an early stage, and I am surprised that the official would say this. Certainly, there appears to be no recognisable wreckage trail and the aircraft seems to lie in a confined area. Due to the hard nature of the rock scree surface and its steep angle, I presume that the aircraft descended at a steep relative angle, either stalled/slow or in autorotation. Speed would seem to have been relatively slow, not high. The wing appears to be complete and the right engine in place. Despite the relative slow speed, the hard surface and a steep descent will have caused the heavy disruption of the forward fuselage structure. Very sad though, that Auntie Ju was not able to force land a little less forcefully.

OAP

[what next]

...and I am surprised that the official would say this....

As I understand it there are several eyewitnesses. And "high speed" for such an aircraft is not the same as for a modern one. Even in a vertical dive it will hardly exceed 150...200kt.

[Onceapilot]

As I understand it there are several eyewitnesses. And "high speed" for such an aircraft is not the same as for a modern one. Even in a vertical dive it will hardly exceed 150...200kt.
Yes, and it wasn't going high speed IMO. That is why I am surprised he said it.

OAP

[glad rag]

It may well just be coincidence that the aircraft has ended up underneath what appears to be the Martinsloch....?https://cimg6.ibsrv.net/gimg/www.gmforum.com-vbulletin/1920x750/martinsloch_introslide3_8053193d02557da1451ca6579ce18caa92e4 751d.jpg

[jimjim1]

The picture we're seeing on avherald has been shot with a telelens and only shows a narrow section of the surroundings. I'd say it's shot about 20 degrees downslope and thus gives the illusion of relatively flat terrain.

The german Wiki-article shows this picture of the crash-area landscape:
https://cimg9.ibsrv.net/gimg/www.gmforum.com-vbulletin/800x1067/800px_martinslochboden_040_643bffb0d3bbbafaad8e45bc74fb318ee d0a5ef4.jpg

The crash-site would be between left of the two distinctive boulders in the center/ center-left of the picture.

They would have been flying upslope (to the right) this valley, probably trying to get over the pass:
https://cimg4.ibsrv.net/gimg/www.gmforum.com-vbulletin/720x501/unt_segnasboden_in_richtung_ofen_2c_tschingelh_c3_b6rner_2c_ segnaspass_35e3f8e6e329a8917046629f68eb9a728751383a.jpg


Note: Since I can't post direct URLs now, you'll have to go the hard way, copy the links into your browser and edit-out the space between "h" and the rest of the link.

Can anybody confirm (or deny) this routing?

Re-posted with images.

[Teddy Robinson]

I was flying in the area yesterday.
ISA +17

[Teddy Robinson]

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]

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]

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]

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






​​

[atakacs]

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

[atakacs]

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]

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]

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]

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 (https://kachelmannwetter.com/ch/messwerte/glarus/windboeen/20180804-1500z.html)

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]

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]

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]

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]

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]

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]

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]

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

[weatherdude]

Just before crash time TCU only left very small gaps in the Segnas Pass area

Sat pic 1445 UTC, other times via menu (https://kachelmannwetter.com/ch/sat/glarus-ch/satellit-hd-5min/20180804-1445z.html)

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

Radar crash time (https://kachelmannwetter.com/ch/regenradar/glarus-ch/20180804-1450z.html)

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?


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

[atakacs]

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]

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.

[Machrihanish]

Just before crash time TCU only left very small gaps in the Segnas Pass area
...
To them, this must have looked like a closed curtain assuming there is no radar in front? ...
Thanks, interesting.

[sycamore]

If the aircraft encountered a significant `downdraft` and a low `G` condition,then the `trail` may well be fuel venting,leading to possible loss of all engines; obviously then requiring a steep descent if it was stalled for a recovery....

[weatherdude]

This was the wind forecast for the area (1x1 km resolution model) for the crash time (6 UTC run)

Direction/10-min-average (https://kachelmannwetter.com/ch/modellkarten/sui-hd/2018080406/surselva/windrichtung-windmittel/20180804-1500z.html)

Gust forecast highest (40-50 kph) in crash site area

Gust forecast Saturday 15z (https://kachelmannwetter.com/ch/modellkarten/sui-hd/2018080406/surselva/windboeen/20180804-1500z.html)

[weatherdude]

The 6z forecast simulated storms in the area for 15 UTC

SigWx forecast for 15UTC (https://kachelmannwetter.com/ch/modellkarten/sui-hd/2018080406/surselva/signifikantes-wetter-erweitert/20180804-1500z.html)

[Sergejev]

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.

Makes a lot of sense EDLB.
So does your hint to the cause of accident.
We know what lack of 'post crash fire' means to the investigator, considering that petrol rather than kerosene is involved, don't we.
Serge

[Machinbird]

Whatever the cause of the vapor trail behind the aircraft, there is one additional piece of glaring information to be gleaned.
The flight path of the aircraft is curving downward, and if you take a tangent to the last part of the curve and compare it to the aircraft attitude, then it is obvious that the aircraft is at a very high angle of attack.
Two points from my mountain flying checkout in Colorado 50+ years ago are probably relevant to this accident.

Do your flying in the high mountains before noon.
As much as possible, cross ridge lines at an angle so that minimal turn is required to abort your ridge crossing.

Is there any information as to the flying backgrounds of the crew?

[atakacs]

The flight path of the aircraft is curving downward, and if you take a tangent to the last part of the curve and compare it to the aircraft attitude, then it is obvious that the aircraft is at a very high angle of attack.
Hmm from what source do you assert this ?

[Machinbird]

https://cimg4.ibsrv.net/gimg/www.gmforum.com-vbulletin/974x558/ju52_stall_2_7222137d1ccc5bb78d15abb64838aae7d120f64c.png
Hmm from what source do you assert this ?
The red line represents the flight path. The green line is the aircraft pitch axis.

Simple. Mark 1 Mod 0 eyeball.

[atakacs]

Well I would be very reluctant to make any such assumption on the basis of a single picture.
Any info on the video this is supposedly extracted from ?

[FL0]

Swiss news portal 20 Minuten quotes an eye witness, a military pilot, who witnessed the aircraft shortly before crash. He claims the plane was in a left turn, when it suddenly pitched left forward, which reminded him of a manoeuvre in case of an engine failure. After that he heard an engine rev up and the plane assumed normal flight again.

I live close to the Ju-Air base in Dübendorf and used to see them on approach. I always wanted to take a flight on them, but I never came to it. It may remain so I'm afraid.

[spoon84]

From the picutres it doesn't look smoke but only the different colour of the mountain ridge.

Said that I'am really shocked with this incident and I think that there are some elements that can already give us an idea of a scenario. I think that it's plausible to assume that they probably try to cross the pass to the north but maybe were not at the correct altitude (8700 ft) and decide to continue straight ahead to gain altitude or make a 180° left turn which led to a stall.

For me there are some elments which have to be verified, like pilot incapacitation, technical problem and/or fuel leak, but it's really clear that the vertical impact at high speed, it's the consequence of a stall. :{

[His dudeness]

Is there any information as to the flying backgrounds of the crew?

From JU-Airs Webpage:
2 Captains flying
Der eine Kapitän war 62 Jahre alt und mehr als 30 Jahre lang Linienpilot. Er flog mehr als 30 Jahre bei Swissair und Swiss, zuletzt als Kapitän auf Airbus A330 und A340. Bei der Luftwaffe flog er insgesamt 28 Jahre als Militärpilot. Seit 2004 flog er regelmässig JU-52 der JU-AIR. Er hatte auf dem Muster bereits 943 Flugstunden und war damit einer der erfahrenen Piloten der JU-AIR.


One captain was 62, with more than 30 years experience as airline pilot. He flew 30plus years with Swissair and Swiss, last as captain on A330/340. He was also a military pilot with the Swiss Airforce for 28 years. Since 2004 he regularly flew JU 52 and hat 943 hours on the type, making him one of the most experienced pilots of JU-Air

Der zweite Kapitän war 63 Jahre alt und seit 2013 bei JU-AIR; er hatte 297 Stunden Flugerfahrung auf der JU-52. Er war 30 Jahre Militärpilot bei der Luftwaffe und mehr als 30 Jahre Linienpilot bei Swissair, Swiss und Edelweiss – zuletzt als Kapitän auf Airbus A330 und A340.

The second captain was 63 and with Ju-Air since 2013 - 297 hours on the JU-52. He was for 30 years a military pilot and more than 30 years an airline pilot with Swissair, Swiss and Edelweiss - his last position was Captain on A330/340.

I guess it will be hard to find people that know more about mountain flying in Switzerland than these guys. With that background they probably knew every rock in the Swiss Alps with their first name....

[meleagertoo]

I'm a little sceptical that the purported "smoke" is associated with the aircraft at all. It could easily be a merterological effect or even colour on the terrain beyond. The angles look odd to me. Had it made that much smoke eyewitnesses would surely have noticed and commented. We also have no idea at what stage of the flight it occurred, or even if it is video of the same flight so until we see the entire video I fear it tells us very little.

From another forum; post #4 is interesting.
http://www.ybw.com/forums/showthread.php?505144-JU52-Crash

[clearedtocross]

There is no need for engine trouble to cause such an accident. This aircraft flew at or above its service ceiling: fully loaded, ISA +17 Celsius. Crash site is at approx. 8500 ft plus the 500 ft you should clear any surface plus nearly +3000 ft density altitude for temperature above ISA adds up to about 12'000 ft density altitude. The BMW radials fitted have much less power than the former Luftwaffe engines (500+ instead of 800+ HP) and are normaly aspirated. Which means that the aircraft was cruising at max. power (which is maybe half of its sea level power) and somewhere near 1.3 times above its rather low stall speed. Now add a 360 for sightseeing and a little bit of turbulence and it may have simply stopped flying even with all motors running perfectly. What adds to this tragedy is that this is the 3rd fatal accident in Switzerland within a few days where high density altitude was probably a contributing factor. 28 persons dead who were all looking forward to beautiful adventure. Sad indeed. The JU-52, after passing the highest obstruction on its flight path, the Lukmanier-Pass which can be overflown safely at 8000 ft, could have reached its destination following down the Rhine valley with no further obstacles to its destination in Duebendorf (LSMD). So it is not inherently dangerous to fly old hardware, but tactics require to honour their lower limits.

[Daysleeper]

But, is anyone being forced to fly on them? I think it's up to the individual to make that decision. If it worries you then don't do it. I fly on vintage aircraft and feel just as safe as I do on modern aircraft. As you may have noticed, they have a tendency to crash too now and again!

The question is one of informed consent. The commercial air transport industry is exceptionally safe (considering what it does) however a lot of those safety advances don't apply to a 1930s built aeroplane. Do the public truly understand the difference between a modern airliner with certificated 16G passenger seat assembly and one that isn't? Or a performance A aeroplane with whatever a JU-52 is?
You may leave the decision up to the individual, but what if they are not capable of making that decision?

[Lookleft]

Would it be a reasonable assumption to make that with the current hot weather in Europe that the pilots have been caught out by the high density altitudes? Clearedtocross makes a very good point.

[Kerosene Kraut]

Swiss media seem to report an eyewitness account by some Swiss military pilot on the ground from ten minutes before the crash who claimed to have seen the aircraft stalling when banking left and recovering with high engine power. If the conditions were so marginal there had been other routes available away from high terrain.

Tagesanzeiger.ch/Newsnet spoke with a witness, a military pilot from the region. He was in his garden when he heard the loud and familiar buzzing of the Ju-52. He believes that the pilots had a serious control problem. He watched as the plane flew across the valley, made a left turn - and then abruptly flipped left ahead. "Such maneuvers were done earlier to simulate the failure of an engine. But nobody does that to passengers, "he says. Then an engine howled loudly, seconds later the plane was balanced again and continued the flight normally.​​​​​​​

https://www.tagesanzeiger.ch/schweiz/standard/senkrechter-sturz-einer-ikone/story/30287960

[robmckenna]

There is no need for engine trouble to cause such an accident. This aircraft flew at or above its service ceiling: fully loaded, ISA +17 Celsius. Crash site is at approx. 8500 ft plus the 500 ft you should clear any surface plus nearly +3000 ft density altitude for temperature above ISA adds up to about 12'000 ft density altitude. The BMW radials fitted have much less power than the former Luftwaffe engines (500+ instead of 800+ HP) and are normaly aspirated. Which means that the aircraft was cruising at max. power (which is maybe half of its sea level power) and somewhere near 1.3 times above its rather low stall speed. Now add a 360 for sightseeing and a little bit of turbulence and it may have simply stopped flying even with all motors running perfectly. What adds to this tragedy is that this is the 3rd fatal accident in Switzerland within a few days where high density altitude was probably a contributing factor. 28 persons dead who were all looking forward to beautiful adventure. Sad indeed. The JU-52, after passing the highest obstruction on its flight path, the Lukmanier-Pass which can be overflown safely at 8000 ft, could have reached its destination following down the Rhine valley with no further obstacles to its destination in Duebendorf (LSMD). So it is not inherently dangerous to fly old hardware, but tactics require to honour their lower limits.

Most sentient observation on this topic yet. Salut.

[spoon84]

They didn't cross the LukmanierPass (6286 ft), they did cross the GreinaPass (7739 ft) which is actually higher and narrow than Lukmanier.

[Arkroyal]

Maths was never my strong subject, but from the pilot resumés it seems they’ve both been flying from the age of 4?

[garpal gumnut]

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






​​

This is a moot point.

+1

[hoss183]

Maths was never my strong subject, but from the pilot resumés it seems they’ve both been flying from the age of 4?
One can fly for commercial and military at the same time.

[Alpine Flyer]

The BMW radials fitted have much less power than the former Luftwaffe engines (500+ instead of 800+ HP) and are normaly aspirated.

According to the Ju-Air website their airplanes have BMW 132A3 engines which according to Wikipedia have a take-off rating of 725hp and a continuous rating of 550hp (of which app. 500hp are used in cruise according to Ju-Air), so the power loss at that altitude would not be that dramatic.

JU52s were never build or regulated to CS25. Yes the company has a Swiss AOC as the aircraft must have done so to carry pax.

I don't think that this operation is certified according to normal passenger transport standards as it is performed by an association (like the Swiss Connie) and you have to be a member to take part in the flights. I hope this modus of operation will not be closed as a result of this accident and the opportunity to get a first-hand experience of flying 1930's (or any later era's) style will remain open to an informed public willing to take the risk

There will inevitably come a day when the last piston airliner will have to be shut down for the last time and reduced to a static display, but I hope that this day is still well in the future.

[BizJetJock]

Arkroyal, a lot of Swiss military flying is done by reservists, so some of their airline time will have been concurrent.

[Double Back]

I don't know if the two-day trip schedule was a one-off, compared to normal operations which I suppose will be hourly or day trips. A cancellation isn't a big thing then. But here we have a group that is more or less expecting to fly home in time (at least the day that was planned). It must have put extra pressure on the guys up front, to at least give it a try.
These operators/organisations/clubs need cash flow to continue flying their expensive planes.
Here in our country an organization that operates a Catalina has been forced to stop due to lack of cash flow. Because last Year it was involved in a minor incident (stuck nose gear) and the resulting time it took to get repairs done, took out the best part of the flying season, depleting the little reserves that were there.
Many of these clubs lack the deep pockets like Red Bull has to keep everything in mint condition and don't care if a show or trip gets cancelled.

[lowfat]

Maths was never my strong subject, but from the pilot resumés it seems they’ve both been flying from the age of 4?


Its not unusual for pilots to have 2 careers concurrently in many countries think of the air national guard in america.

[EDLB]

There is no need for engine trouble to cause such an accident. This aircraft flew at or above its service ceiling: fully loaded, ISA +17 Celsius. Crash site is at approx. 8500 ft plus the 500 ft you should clear any surface plus nearly +3000 ft density altitude for temperature above ISA adds up to about 12'000 ft density altitude. The BMW radials fitted have much less power than the former Luftwaffe engines (500+ instead of 800+ HP) and are normaly aspirated. Which means that the aircraft was cruising at max. power (which is maybe half of its sea level power) and somewhere near 1.3 times above its rather low stall speed.

Complete rubbish.
Did you ever cross mountains in a piston engine? The Ju52 will go up to 18000 feet outperforming a typical C172 and any Homo sapiens not on oxygen. 12.000 feet density altitude is nothing special. You can go to 14.000 feet without oxygen for half an hour. You will feel a bit tired and that improves with every 500 feet you go down.

Here two experienced captains where faced with a problem they could not solve and that was definitely not a density altitude problem. It might be one additional hole in the cheese but not the definite one for the outcome.
From what I see on the terrain, they could have maid it to an emergency landing even without any power. So there is more to the story.

[Kerosene Kraut]

Bit rude aren't we?

[Annex14]

Ref. that Swiss TV picture(screenshot)
It appears unrelated to the crashed flight!! The Text attached to that TV picture only says: One of the last pictures of the flight. Neither does it state wether that JU52? is actually HB-HOT, nor does it state the date when the picture was taken. Good guess it is just the normal journo crap - Mr. T would call it "fake news"
Canton Glarus is north of the crash site. Enter "Chamm, Glarus" on Google Earth (Maps) and it will show a mountainous place to the north of the accident site. It´s nowhere said or written that they crossed that ridge next to "Martinsloch" and returned crossing that ridge again !!

[clearedtocross]

Complete rubbish.
Did you ever cross mountains in a piston engine? The Ju52 will go up to 18000 feet outperforming a typical C172 and any Homo sapiens not on oxygen. 12.000 feet density altitude is nothing special. You can go to 14.000 feet without oxygen for half an hour. You will feel a bit tired and that improves with every 500 feet you go down.

Here two experienced captains where faced with a problem they could not solve and that was definitely not a density altitude problem. It might be one additional hole in the cheese but not the definite one for the outcome.
From what I see on the terrain, they could have maid it to an emergency landing even without any power. So there is more to the story.


Thank you for the flowers, dear EDLB. Yes, I did cross the mountains many time on a piston engine. Thats why I consider myself as qualified to talk "rubbish". What's really rubbish is the ceiling cited in Wikipedia, at least for the JU-52 operated nowadays.
Let's see what the accident investigation has to say about this.

[EDLB]

Sorry, I like in no way to offend you. Keep in mind that a lot of jurnos with no clue whatsoever are reading here and it does not help to jump to conclusions too early.

[zero/zero]

Ref. that Swiss TV picture(screenshot)
It appears unrelated to the crashed flight!! The Text attached to that TV picture only says: One of the last pictures of the flight. Neither does it state wether that JU52? is actually HB-HOT, nor does it state the date when the picture was taken. Good guess it is just the normal journo crap - Mr. T would call it "fake news"
Canton Glarus is north of the crash site. Enter "Chamm, Glarus" on Google Earth (Maps) and it will show a mountainous place to the north of the accident site. It´s nowhere said or written that they crossed that ridge next to "Martinsloch" and returned crossing that ridge again !!

I think the word you’re looking for is that the picture/screengrab is “unverified”.

That doesn’t mean it’s the same as “fake news”

[ZFT]

The question is one of informed consent. The commercial air transport industry is exceptionally safe (considering what it does) however a lot of those safety advances don't apply to a 1930s built aeroplane. Do the public truly understand the difference between a modern airliner with certificated 16G passenger seat assembly and one that isn't? Or a performance A aeroplane with whatever a JU-52 is?
You may leave the decision up to the individual, but what if they are not capable of making that decision?

And who decides that? I was lucky enough to fly on a B17 and no one dared question my ability to determine if it was safe. That was my decision.

[Bend alot]

16g is the shorthand for the certification standard for new production passenger seat assembly. (the actual standard is quite complicated with various static and dynamic loads and directions)

Why would it hinder survival?

How many can and do survive 16G seat loads.

I am aware of the standard, just doubt it is practical since they are happy with standard weights in such tests.

[Pilot DAR]

How many can and do survive 16G seat loads.

Last summer I survived a crash where I was ejected through the windshield, having ripped out the 9G seat and seatbelt. That means my body was subjected to a minimum of 12G, though more likely 15G. That causes injuries, though is survivable. Through the evolution of the standards, seat and seatbelt strength requirements have been made more demanding - for the most part, going from less than 6G calculated, through 9G static load test to 18G dynamic load test. I have done STC approval projects on vintage aircraft for modernized passenger carrying (Grumman Goose was one), generally in such cases, more modern standards are applied to the STC approval. I have no specific knowledge of the Ju52, though I would think it might have had a seat refit done prior to re-entering passenger carrying service, and common practice would have that seat refit done to a stronger standard than original. That said, from the crash photos, it does not appear that seat strength would have been a factor in surviveabilty.

[hunterfate]

There is a very nice video of sister plane flying through the beautiful Swiss landscape on Youtube under title "Junkers Ju 52 -> Tante JU Spectacular Flight through Swiss Alps from Gstaad"
(I can't post URL's yet).

May they rest in peace.

[SATCOS WHIPPING BOY]

https://cimg1.ibsrv.net/gimg/www.gmforum.com-vbulletin/800x450/screenshot_2018_08_05_13_59_52_509c84250418701b816e3e67a1edb 61f372308ac.jpg

[His dudeness]

I think that applies to a multitude of daily activities and is very much an attitude which has led to the nanny state environment we now live in.

Exactly.

There are millions of cars on our streets that don´t have the latest safety equipment build in. Scrap em ! (?)

[Annex14]

I think the word you’re looking for is that the picture/screengrab is “unverified”.

That doesn’t mean it’s the same as “fake news”


Hello Z/Z
thanks for the kind help. However I intentially used the word "unrelated". The outgoing flight from Dübendorf to Locarno went via the Gotthard Massiv.The Gotthard routing is well west of the Chamm mountain area in Kanton Glarus. The return flight followed a more easterly rounting to cover the "highlight" Martinsloch, the hole in the rockwall of that ridge they wanted to cross. The accident site is still within the limits of Kanton Graubünden / Grisons .
So neither on the flight on August, 3 nor on the return flight on August,4 HB-HOT could be spotted in the Chamm Mountain Area before the accident.
In my opinion, what happened here is a journalist in a great hurry wanted to sell his story first, grabbed whatever picture or video of a JU 52 flying in the mountains and added it to his/her report.
I use to call such an approach to the facts of a story "Journos crap" and as side kick to the plague of the "Twitter King" in the US I have named it like he would do.
Just for info!!
Jo

[Super VC-10]

Thank you for the flowers, dear EDLB. Yes, I did cross the mountains many time on a piston engine. Thats why I consider myself as qualified to talk "rubbish". What's really rubbish is the ceiling cited in Wikipedia, at least for the JU-52 operated nowadays.
Let's see what the accident investigation has to say about this.

That an operator of a certain type of aircraft decides to impose a lower ceiling than previous operators have done before, or that the aircraft has been certified to before, does not mean that the previously certified ceiling is invalid.

[spoon84]

There was a statment today in the media of the owner of a mountain lodge of the Segnespass, which said that it was everything normal as the airplane always did, but after a left turn (completed) the plane just fall off the skies like a stone. He also said that there were people at about 150 . 200 meters of the crash that were in his lodge. He did went there to assit but everyone was dead.

You can check the Mountain Lodge here: Segnespass (http://www.segnespass.ch/)

and the news here: https://www.tio.ch/svizzera/cronaca/1313360/ha-fatto-una-curva--poi-e-venuto-giu-come-un-sasso-

[Alpine Flyer]

An undated (and probably reprinted) factory sales brochure for the Ju52/3m lists the following data:

1980hp total for 3 BMW 132A engines

service ceiling 19030ft (20350 with variable pitch props), OEI 9520ft (10830 with variable pitch props)
(Can't tell from online pics whether props are variable or fixed pitch, looks more like the latter and absence of manifold pressure gauges on flight deck pics would also hint at that.)

MTOM 10t (22000lb.)

[pattern_is_full]

Just a reminder - since it hasn't been mentioned yet - that what counts in a stall is AoA, not a particular speed. Making a 180° turn in a narrowing valley may require a rather steep bank to avoid the valley walls, with associated G forces (accelerated stall). If there is altitude below one, one can unload the wing a bit with a descent in the turn (a bit of forward stick to lower AoA). But maybe the space isn't there.

The crash location (see top photo post #51) looks like a classic "box canyon," which have killed many fliers, and even if the "numbers" say it should be a piece of cake (ein klacks?) to outclimb the terrain, factors such as +ISA, downdrafts or other turbulence, the angle of the valley floor, weather seen on the far side of the ridge or pass, etc. can all cut off one's options rather rapidly. Even a competent, experienced pilot/crew can get trapped, if the holes in the cheese line up fast enough.

I am - equivocal - about machinbird's image and analysis. Only because I know how much a telephoto lens' compressed "perspective" can sometimes distort visual geometry, and because without motion, I am not full persuaded the "smoke trail" is not, perhaps, a highlight on the exposed mountain rock in the background, or other artifact. It is suggestive, but not definitive.

The observer descriptions (however flawed) and the aircraft condition/position are strongly suggestive of a stall/spin.

I'm also not persuaded by the idea that the terrain was suitable for a survival emergency landing. The terrain immediately around the crash site is even, but there may be a substantial "flat" downslope that would make braking and deceleration difficult, and of course even a Junkers doesn't land like a helicopter - it takes several hundred meters/yards of rollout, and who knows what obstructions, dips and boulders were "just outside the frame" in the photographs. I live and fly in the Rockies, and there many places above the tree line here (tundra) that "look flat" from 1000 feet AGL, but would be disastrous to actually try and land and stop on.

The only person I knew personally, who died in an aircraft accident, died in a direct dive into mountain valley terrain. Very similar to this accident. He was a pilot but acting as a photographer in the right seat when he died. His last pictures showed they were low over trees, straight and level. Exactly what put them into a dive was never determined.

[Airbubba]

I had a colleague do an approach to stall with pax onboard in an A310 over the Alps years ago. He wanted to show the folks some scenic alpine valley and got permission from ATC to do a couple of orbits. He turned off the autothrottles and autopilot and wrapped up the bank as he looked out to keep the landmark in view. Nobody was minding the store and the airspeed dropped until the red bars came up on the PFD tape and alpha floor was triggered. The throttles automatically reengaged and went to full TOGA thrust.

The A310 is somewhat overpowered and short-coupled for a widebody and the pitch change when both engines come up is impressive. After some minor aerobatics control was restored and the flight continued on its way. No harm, no foul except a fed and his wife were onboard in the back and reported the incident. The TXL-based crew got first class tickets to MIA for some extra sims.

[beamer]

Just a reminder - since it hasn't been mentioned yet - that what counts in a stall is AoA, not a particular speed. Making a 180° turn in a narrowing valley may require a rather steep bank to avoid the valley walls, with associated G forces (accelerated stall). If there is altitude below one, one can unload the wing a bit with a descent in the turn (a bit of forward stick to lower AoA). But maybe the space isn't there.

The crash location (see top photo post #51) looks like a classic "box canyon," which have killed many fliers, and even if the "numbers" say it should be a piece of cake (ein klacks?) to outclimb the terrain, factors such as +ISA, downdrafts or other turbulence, the angle of the valley floor, weather seen on the far side of the ridge or pass, etc. can all cut off one's options rather rapidly. Even a competent, experienced pilot/crew can get trapped, if the holes in the cheese line up fast enough.

I am - equivocal - about machinbird's image and analysis. Only because I know how much a telephoto lens' compressed "perspective" can sometimes distort visual geometry, and because without motion, I am not full persuaded the "smoke trail" is not, perhaps, a highlight on the exposed mountain rock in the background, or other artifact. It is suggestive, but not definitive.

The observer descriptions (however flawed) and the aircraft condition/position are strongly suggestive of a stall/spin.



My thoughts were the same. The terrain looks challenging and visual illusions are all to easy to encounter. A 180 turn to escape from a box valley could be very challenging in an old aircraft even for very experienced pilots.

[Blohm]

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 (https://kachelmannwetter.com/ch/messwerte/glarus/windboeen/20180804-1500z.html)
I don't know the true, but what is kph? Kilometers per hour, as in kmh or is it kts? (Natical miles per hour). I am used to kts in this context.

[Machrihanish]

what is kph? Kilometers per hour
This.




_

[DaveReidUK]

I was lucky enough to fly on a B17 and no one dared question my ability to determine if it was safe.

That doesn't necessarily mean that your determination was sound. It may have been unsafe, but you were (in your own words) "lucky enough".

[ORAC]

Valleys bite.

ASN Aircraft accident Lockheed Hercules C.3P (C-130K) XV193 Blair Athol (http://aviation-safety.net/database/record.php?id=19930527-0&lang=en)

[weatherdude]

I don't know the true, but what is kph? Kilometers per hour, as in kmh or is it kts? (Natical miles per hour). I am used to kts in this context.

=Kilometers per hour. Divide by 1,852 for knots.

[ATC Watcher]

I do not buy the sudden CB blocking the way , the 180 in a tight valley and the subsequent stall. Those guys were not amateurs ,they were locals to the area and knew the aircraft well. Anyone flying deep in the Alps knows how and when to go back ( and how to do, or not to do , a 180 in a valley, and with such a slow aircraft should not be a real issue anyway ),
The aircraft might not have radar but today with an IPad and Meteox you know exactly where the cells are and where they go . Finally a stall in a Ju52 would not pitch down the aircraft to a vertical dive as suggested .

[BARKINGMAD]

Neill Williams some years ago?? And he was more of a "raw" flyer than 2 very experienced 'bus' drivers? ��

[ZFT]

That doesn't necessarily mean that your determination was sound. It may have been unsafe, but you were (in your own words) "lucky enough".

So you are questioning it?

I also thought it was pretty obvious the luck was referring to the event, not the survivability of it!

[weatherdude]

This is a very funny idea that you want to see TCU and showers just starting on the ridiculously bad resolution (4 to 8 times worse than the real thing) on Meteox.


I do not buy the sudden CB blocking the way , the 180 in a tight valley and the subsequent stall. Those guys were not amateurs ,they were locals to the area and knew the aircraft well. Anyone flying deep in the Alps knows how and when to go back ( and how to do, or not to do , a 180 in a valley, and with such a slow aircraft should not be a real issue anyway ),
The aircraft might not have radar but today with an IPad and Meteox you know exactly where the cells are and where they go . Finally a stall in a Ju52 would not pitch down the aircraft to a vertical dive as suggested .

[ATC Watcher]

This is a very funny idea that you want to see TCU and showers just starting on the ridiculously bad resolution
It is quite accurate in central Europe and we use it, combined with sat 24 , and it works quite well but mostly to delay take off or change routings, but not to circumnavigate cells as you do with an on board radar,
If you do not have on board wx radar meteox is a good tool to keep you out of trouble.

[gearlever]

Today BAZL cancelled ban on JU 52.
JU-AIR resuming flights per 17th August.

Hhm, does this mean BAZL know already what went wrong?

[Armchair_Ace]

This was the aircraft used in the movie Where Eagles Dare. Swiss Air Force A-702. Tragic loss of life.
https://cimg2.ibsrv.net/gimg/www.gmforum.com-vbulletin/1014x429/where_eagles_dare4_4f12e097cf16bd8e0235c394066f66b1caac66be. jpg

[weatherdude]

Again, the echoes in my earlier post never showed up. Also try to see small areas like those in the blog post on sat24

Blog with satellite and radar links on weather/crash site (https://blog.tagesanzeiger.ch/wettermacher/index.php/577/absturz-der-ju-52-welche-rolle-spielte-das-wetter/)


It is quite accurate in central Europe and we use it, combined with sat 24 , and it works quite well but mostly to delay take off or change routings, but not to circumnavigate cells as you do with an on board radar,
If you do not have on board wx radar meteox is a good tool to keep you out of trouble.

[Machinbird]

Finally a stall in a Ju52 would not pitch down the aircraft to a vertical dive as suggested . I sort of agree with you. an aggravated stall will not bobble the nose up and down the way AF447 did. Instead, an aggravated stall will induce a roll to inverted and the aircraft will dive. These older aircraft typically have rather rapid roll off in a stall.

In earlier posts, I mentioned the downward curvature of the vapor trail in the screen grab. This indicates steepening of the flight path, which if while maintaining a constant attitude, results in an increasing angle of attack. This was a 'gotcha' that D.P.Davies warned of in his book,"Handling the Big Jets." It would seem that the warning also applies to piston aircraft operating near their ceiling.

I too wondered whether the screen grab was significant since it was described as a picture of the aircraft shortly before the crash. When I saw the degree of angle of attack on the aircraft, it was clear that the aircraft was in extremis if the vapor trail was what it appeared to be. Following the vapor trail back, it became semi-transparent as a real vapor trail would. The fact that someone had already circled it meant that it was likely significant. Finally, did you ever ask why we only have a screen grab instead of the original video? I think it likely that the video would have been very distressing to those who saw it, but you can bet the accident board has seen it.

[Skyborne Flyer]

In earlier posts, I mentioned the downward curvature of the vapor trail in the screen grab. This indicates steepening of the flight path, which if while maintaining a constant attitude, results in an increasing angle of attack. This was a 'gotcha' that D.P.Davies warned of in his book,"Handling the Big Jets." It would seem that the warning also applies to piston aircraft operating near their ceiling.

I too wondered whether the screen grab was significant since it was described as a picture of the aircraft shortly before the crash. When I saw the degree of angle of attack on the aircraft, it was clear that the aircraft was in extremis if the vapor trail was what it appeared to be. Following the vapor trail back, it became semi-transparent as a real vapor trail would. The fact that someone had already circled it meant that it was likely significant. Finally, did you ever ask why we only have a screen grab instead of the original video? I think it likely that the video would have been very distressing to those who saw it, but you can bet the accident board has seen it.
I believe the video was said to be of a previous flight, a previous poster stated that the view is from a different region, that the accident flight did not traverse, and therefore has no bearing to the chain of events leading to the crash.

[HarryMann]

Density altitude as KK says well above... think.maybe rotor effect too. iOW staggering about unknowingly far too near a stall and turning such a large span effectively downwind.
In some aviation circles, theres a term called 'tip stall' where the inner tip in a turn drags back and drops.
Unless a wing engine did just 'let go' which will likely be discovered if so...
So tragic... indeed, fate is the hunter.

[Volume]

Is there anybody here who has actually flown a Junkers with the "Doppelflügel" (Double Wing) aileron desgn? Like the Ju 52, T 29 or the Ju 86? It is a quite unique design with a fixed main wing and a smaller, moveable wing trailing the main wing which acts as flap and control surface. How efficient is it at low speed? Does it tend to reverse close to stall? Does it produce significant adverse yaw?
The Ju 52 has a relatively highly tapered wing and small ailerons, how forgiving is it close to stall?

There probably is a reason why this design disappeared post WWII.... And probably the end of Junkers is not the only one, as many other design features of german manufacturers were picked up by the aviation world.

Does anybody know the elevator trim system of the Ju 52? When hearing about the sudden dive, alaska air trim actuator failure comes to mind. First dive recovered, second dive fatal.
As BAZL does allow the Junkers to fly again, obviously they have ruled out technical failure already ?

When talking low density altitude, higher stall speed is only one aspect. What I found more remakable, especially in the mountains, is that the radius of any turn also increases significantly. You simply need more space to maneurve if the density altitude is high. Typically you do not notice this, but in the mountains it is a different story.
So you have 3 adverse factors: Higher stall speed, less engine power and less space to maneurve. Might be one too much...

[Kerosene Kraut]

Just for clarification: BAZL has never stopped the Ju 52 from flying. So no need for some permission to fly again.
Ju Air has only paused it's own flights until I think mid august.

[EDLB]

What I found more remakable, especially in the mountains, is that the radius of any turn also increases significantly. You simply need more space to maneurve if the density altitude is high.

Not surprising. Your true speed is faster in less dense air. But as long as you fly IAS that should not be a big factor. Compared to higher performance planes you can still turn on a dime with that slow bird. I would be surprised if the PF did deliberately accelerated manoeuvres with a load of paying customers.

[clearedtocross]

An undated (and probably reprinted) factory sales brochure for the Ju52/3m lists the following data:

1980hp total for 3 BMW 132A engines

service ceiling 19030ft (20350 with variable pitch props), OEI 9520ft (10830 with variable pitch props)
(Can't tell from online pics whether props are variable or fixed pitch, looks more like the latter and absence of manifold pressure gauges on flight deck pics would also hint at that.)

MTOM 10t (22000lb.)

The Ju-Air homepage states max continuous 500 per engine, so 1500 hp total. MTOW is 10 t which gives 6.6kg per hp. The oldest version of a C172 had 145 hp on roughly 1000 kg MTOW, so the power to weight ratio is more or less the same! And then, Mr. Junkers designed a load carrier, not a sleak performer. The JU-52 is a drag queen. The very crew of the perished aircraft commented to that fact a couple of years ago in an aviation journal. The factory specs are irrelevant, they were issued during the Third Reich where engines were dispensable and propaganda important. Nowadays, an overhaul of a BMW radial leads to prohibitive cost for a non-profit operator. Though the homepage of JU-Air says the power is reduced due to noise considerations, but I think going easy on these motors is the real reason for reducing max. continuous. Some people quote also that the engines were modified to run on leadless Mogas. Now its anybodies own guess to what altitude you can climb with such a ship with a full passenger load on a hot day.

[wiggy]

May well not be at all relevant to the subject of this thread but on the subject of mountain flying it is widely believed that the experienced captain in this accident thought they could out climb a slope ...and failing that thought they could turn inside a valley...

https://aviation-safety.net/database/record.php?id=20031217-0

[HarryMann]

Not surprising. Your true speed is faster in less dense air. But as long as you fly IAS that should not be a big factor. Compared to higher performance planes you can still turn on a dime with that slow bird. I would be surprised if the PF did deliberately accelerated manoeuvres with a load of paying customers.

Alll very true... but from what Ive noticed, IAS and turn rate when well away from ground rarely leads to stalls. Turning in close sight of ground and where wind gradient may exist is different... this is the regime of low speed and low altitude flight, and tight turns in gradient winds... gliding, microlighting etc.

[fdr]

Sad end to an old lady and the occupants.

The photo geometry may be adding some foreshortening, but the aircraft would appear to be in a relatively nose high attitude. The attitude itself is not indicative of AoA, except that where there is limited performance, there is not too much opportunity to trade "speed for height". If any video survived the event, then it may be able to reconstruct the speed using broadband noise SPL, there is substantial airflow noise on these types of aircraft. Any engine faults may also be detected through video with a spectral analysis. The choices of causation for a steep flight path impact in clear weather are fairly limited, and will be able to be determined from the wreckage that remains. The State investigators will do a comprehensive analysis, and will most likely determine the probable cause of the accident.

Operating limited performance aircraft in rugged terrain can be challenging, even without other factors stressing the op. I for one would hate to see excessive regulatory response to the operation of the older aircraft types, they provide an insight into where we have been and thereby give some meaning to where we are. There is inherent risk, but then we dont get out of life alive, and we are here for the experience.

RIP to all on board.

PS, I still fly some WWII aircraft, and others around the Korean war vintage. They are different, exude character, but they are different.

[Saint-Ex]

I have a few hundred hours on the JU52. "Volume" asked about the elevator trim. The large elevator trim wheel has a selector to enable it to also wind down the flaps. I found the aircraft very forgiving and there was nothing unusual about the stall. We really have to allow the investigators to do their part in finding out what happenned to this remarkable aircraft.

[jimjim1]

https://cimg1.ibsrv.net/gimg/www.gmforum.com-vbulletin/790x444/bild_fbb788d3c8e1812ca10e0f4c0cab49718a5bd90a.jpg

I think that this may be a better version of the image. Image is 790x444, make your browser wide enough for best view.

For the "smoke" to be such a wide trail at the aircraft a large fire would seem to be necessary. There is no sign of fire at the crash site.

Grass, not smoke.

This is still a very poor image, 20k jpeg. Someone may well have a better one.

Source -
"https://www.srf.ch/var/storage/images/_aliases/944w/auftritte/news/bilder/2018/08/05/node_16198592/178592648-2-ger-DE/bild.jpg"

[skadi]

https://cimg1.ibsrv.net/gimg/www.gmforum.com-vbulletin/2000x1504/376950_e0c5f4fa0300db1c2bf3db540a570162bb0b72b6.jpg
Piz Segnas (https://www.summitpost.org/piz-segnas/154862)
This is a picture of the area in wintertime, the right summit is Piz Segnas. The sunny snowfield left of Piz Segnas has the same appearance as the "smoketrail" in the pic with the JU.

skadi

[krohmie]

Cover of the PDF,

Not the first time in this place!

https://www.ju-air.ch/app/download/7021349551/Gazette-2018.pdf

[sir]

https://cimg1.ibsrv.net/gimg/www.gmforum.com-vbulletin/2000x1504/376950_e0c5f4fa0300db1c2bf3db540a570162bb0b72b6.jpg
Piz Segnas (https://www.summitpost.org/piz-segnas/154862)
This is a picture of the area in wintertime, the right summit is Piz Segnas. The sunny snowfield left of Piz Segnas has the same appearance as the "smoketrail" in the pic with the JU.

skadi

I agree. I think this view is Segnas from the Glarus side of the ridge, the Tschingelhörner would be to the right of this picture. This would be consistent with the claim the photo of the aircraft with ‚smoke trail‘ was taken in Chamm, Glarus and that is categorically not an image of the accident. The accident occurred on the other side of the ridge on the Graubünden side.

[skadi]

I agree. I think this view is Segnas from the Glarus side of the ridge, the Tschingelhörner would be to the right of this picture. This would be consistent with the claim the photo of the aircraft with ‚smoke trail‘ was taken in Chamm, Glarus and that is categorically not an image of the accident. The accident occurred on the other side of the ridge on the Graubünden side.
I think, the lowest part of the ridgeline in the very right part of the Pic must be the Segnas Pass, so the crashsite is just behind.

skadi

[sir]

I think, the lowest part of the ridgeline in the very right part of the Pic must be the Segnas Pass, so the crashsite is just behind.

skadi

Agreed, the Hüttenwart (lodge keeper) at the Segnashütte said in his interview that the aircraft began a left turn before falling - for me a left turn would mean towards the pass / ridge as if attempting to make the crossing. No idea how close to the Tschingelhörner ridge side they flew though as they headed up that valley.

[skadi]

Agreed, the Hüttenwart (lodge keeper) at the Segnashütte said in his interview that the aircraft began a left turn before falling - for me a left turn would mean towards the pass / ridge as if attempting to make the crossing. No idea how close to the Tschingelhörner ridge side they flew though as they headed up that valley.The Hüttenwart stated in another interview that he was inside the lodge and didn't see the crash personally, but others did. So the upcoming report will definitely give some information of the flightpath short before the accident.

skadi

[hoss183]

The limits of the accident photograph are as shown by my red box, ok the point of perspective is more to the right in the first but the same profiles are present.
You can clearly see the feature that appears to be smoke as a ridgeline.
https://cimg5.ibsrv.net/gimg/www.gmforum.com-vbulletin/2000x1500/376950_e0c5f4fa0300db1c2bf3db540a570162bb0b72b6_0ef263c4230d adf588be4941fa59863982db66ff.jpg

[weatherdude]

[QUOTE=jimjim1;10217091]https://cimg1.ibsrv.net/gimg/www.gmforum.com-vbulletin/790x444/bild_fbb788d3c8e1812ca10e0f4c0cab49718a5bd90a.jpg

I think that this may be a better version of the image.

[Volume]

But nevertheless a quite nose-up pitch for the old lady not currently climbing...

[PaxBritannica]

Does anyone know if the Martinsloch itself causes any odd wind phenomena? I came across a blog (http://www.per-net.ch/blog/2011-1166/durchs-martinsloch/)where someone walked/climbed to the Martinsloch and said (translated from German): "A poisonous cold wind blew through the impressive 19 × 17 meter hole. "

[Hadley Rille]

At a high density altitude the relatively higher TAS would get you into a pickle more quickly in a box canyon than at lower altitudes.

At 1000ft AMSL 60kts IAS is 61kts TAS but at 10000ft AMSL it's 72kts TAS.

Would it be enough to make the difference and force a higher turn rate to avoid terrain, edging towards the stall in clean configuration?

[Walking Bird]

On the site of the webcam of Mutta Rodunda (just google it) cable car station you can have a look at the possible crash site if you go back in time 2018-08-04 to 16:40 and 17:00. Below the half-moon shape snow field you see nothing at 16:40, but possibly the JU52 at 17:00. The weather looks not too bad.
I would post the pictures, but I am not allowed to do so yet (less than 10 posts)

[jimjim1]

Thanks to various pointers to this location from poster(s).

From the Streetview viewpoint at this location you get the "grass/smoke" view of Piz Segnas.

https://goo.gl/maps/i2JBbsA3PtC2

https://cimg1.ibsrv.net/gimg/www.gmforum.com-vbulletin/606x459/ju_52_1_147618e574c7544adb5b73cb464decbaa517c8ab.png


Drag the yellow man towards the point.
https://cimg8.ibsrv.net/gimg/www.gmforum.com-vbulletin/606x459/ju_52_2_68379636361f3eeef729c2a49d90abf0c7587b69.png

Drop the Yellow man's circle over the blue circle at the point.
https://cimg5.ibsrv.net/gimg/www.gmforum.com-vbulletin/606x459/ju52_3_f81a0f538d82f38b55942d86d7f43bb80d34ef08.png

Pan right to about 155 degrees and zoom in to get the image below

https://cimg3.ibsrv.net/gimg/www.gmforum.com-vbulletin/606x459/ju52_4_cc8a7b409cd4e4878ba0fb096aa7112c5db11363.png

[PaxBritannica]

On the site of the webcam of Mutta Rodunda (just google it) cable car station you can have a look at the possible crash site if you go back in time 2018-08-04 to 16:40 and 17:00. Below the half-moon shape snow field you see nothing at 16:40, but possibly the JU52 at 17:00. The weather looks not too bad.
I would post the pictures, but I am not allowed to do so yet (less than 10 posts)

This what you meant?


16.40:
https://cimg4.ibsrv.net/gimg/www.gmforum.com-vbulletin/1906x858/piz_segnas_16_40_c557516b4ee96b04c304afda8b5dd971b62cb495.gi f

17.00:
https://cimg9.ibsrv.net/gimg/www.gmforum.com-vbulletin/1912x854/piz_segnas_17_00_ab4f5db5f9f3b02236898efeeaef93ce2343bd96.gi f

Closeup of object, 17.00:
https://cimg3.ibsrv.net/gimg/www.gmforum.com-vbulletin/460x287/piz_segnas_17_00_closeup_8629d653224b1f7aa9b7b6631bdfd3f70f7 ed200.gif


Can't get the resolution any better than that.

[pattern_is_full]

Just to put another cat among the pigeons, Aviation Herald is now quoting "a military pilot" who says he saw the same aircraft, 10 minutes prior to the accident, make a similar left turn that "suddenly" developed into a severe roll and dive, but recovered with high power.

Make of that what you will: Crash: Ju-Air JU52 at Piz Segnas on Aug 4th 2018, impacted terrain (http://avherald.com/h?article=4bbf2069&opt=0)

[derjodel]

How about shifted COG which would cause the high pitch we see in the “smoke” photo and subsequential stall?

Could be as simple as too many people moving aft to see the view or whatever...

[AlterSchwede]

...PaxBritannica, I was about posting the same pictures (looking noth-north-east). Yes, sadly, it clearly shows where the Ju-52 ended. The 16.50 pictures shows shadow over the area so these two, at 16.40 and 17.00 are the clearest ones. With different infos so far available I agree with some other comments here, it was most probably a stall (left wing) accident. (My personal opinion!)
The distance between the mountain ridges is about 900m. In the left ridge we have the Martinsloch (round opening in the mountain). According to other info, ISA was around 17 degree over standard atmosphere. The wind (max almost 20 knots according other info) was from the north (from behind the ridge on the left side).
Now we have to options:
-1) the pilots on the way home, heading north, wanted to fly straight over the ridge (at the lowest point) , but realized that the performance was not good enough, so they were forced to turn back to the south...
or:
-2) the pilots first wanted to show the Martinsloch, flying north-north-east along the right mountainslope followed by a left turn back to the south.

- Considering the fully loaded aircraft, and high ISA +17, the TAS would be greater than at STD atmosphere resulting in a greater turning radius, and... to keep inside the valley they MAYBE had to increase the bank angle.
- At 45° bank the stall speed increase with 20% (1.4G). They most probably used max continues power. What speed? 120 knots? Or even slower (in case 2) due to terrain?
- The north wind, maybe gusting and turbulent, becoming a tailwind component during the last part of the 180 degree turn. It is not hard to imagine that they had small margins, not only scanning the instruments but also to look outside to keep clear of terrain.
I am also wondering, how is the Ju-52 accelerated stall behaviour? With max continues power, in a 30° (or 45°) bank? Probably not so nice. And how is the spiral stability, and what aileron position is required to keep a steady turn? Neutral? All factors influencing such a situation.

[cappt]

Just to put another cat among the pigeons, Aviation Herald is now quoting "a military pilot" who says he saw the same aircraft, 10 minutes prior to the accident, make a similar left turn that "suddenly" developed into a severe roll and dive, but recovered with high power.

Make of that what you will: Crash: Ju-Air JU52 at Piz Segnas on Aug 4th 2018, impacted terrain (http://avherald.com/h?article=4bbf2069&opt=0)

Yes I read that, sounds like a propeller problem, overspeed or loss of prop control.
The "high power" sound may have been the prop overspeeding and causing severe drag on the left engine.
Pure speculation on my part of course.

[scifi]

From a different angle..

https://goo.gl/maps/kyUxtFNtWS12

[spoon84]

Yes I read that, sounds like a propeller problem, overspeed or loss of prop control.
The "high power" sound may have been the prop overspeeding and causing severe drag on the left engine.
Pure speculation on my part of course.


in the online newspaper Blick you can see the last picture of the Ju-52 in a left turn.

https://www.blick.ch/news/schweiz/augenzeuge-sah-den-ju-52-absturz-am-piz-segnas-es-war-ein-bild-des-grauens-id8700276.html

https://cimg6.ibsrv.net/gimg/www.gmforum.com-vbulletin/1964x1098/schermata_2018_08_07_alle_21_00_55_e88281014ecab3898c803fed9 7aea2c569b9dd3d.png

[atakacs]

in the online newspaper Blick you can see the last picture of the Ju-52 in a left turn.
Assuming it is authentic I guess it closes the argument about smoke / vapour or whatever emanating from the aircraft.
Also as far as we can judge from that picture the overall attitude seems about normal. We do get an idea of the terrain below, definitely not smooth but certainly somewhere you could try an emergency landing with such an aircraft in case of a catastrophic engine failure.
Now we have to understand why they apparently completely lost control. I remain perplexed.

[sycamore]

Can also see it`s shadow near the bottom..

[RatherBeFlying]

Upwind would be in updraft.

Downwind could be downdraft and nasty rotors.

Much depends on wind direction relative to terrain, strength and shears. You could be flying in a particular area for years without problems – and one day you get nailed.

[HarryMann]

You could be flying in a particular area for years without problems – and one day you get nailed.

Exactly true... you don't get downwind of a sharp ridge without expecting the unexpected

[cappt]

In the last Blick picture which looks to taken just seconds before the crash the JU52 appears to turning to the North into the wind and toward the headwall of the canyon. The torn white lower cumulus clouds behind it look like rotor clouds. Rotor clouds are a good indication of turbulence and mountain wave associated with wind across the mountain tops.

[sir]

in the online newspaper Blick you can see the last picture of the Ju-52 in a left turn.

https://www.blick.ch/news/schweiz/augenzeuge-sah-den-ju-52-absturz-am-piz-segnas-es-war-ein-bild-des-grauens-id8700276.html

https://cimg6.ibsrv.net/gimg/www.gmforum.com-vbulletin/1964x1098/schermata_2018_08_07_alle_21_00_55_e88281014ecab3898c803fed9 7aea2c569b9dd3d.png

That mountain behind the aircraft is the Atlas. The band of cliffs spans from about 2700m to 2800m elevation. This shows the aircraft was flying up the eastern side of the valley, and the left turn would line them up with the Segnes Pass, of which the lowest point is 2625m rising to 2742m either side. On the webcam photos you see the pass as the lowest part of the ridge on the left side, and you can also see Atlas on the right.

Good map of the area (https://map.geo.admin.ch/mobile.html?topic=swisstopo&lang=de&bgLayer=ch.swisstopo.pixelkarte-farbe&E=2736995.75&N=1195633.88&zoom=9.193964219270255)

[atakacs]

My question would be how much reserve performance could they have flying there with a compliment of 20 passengers on a hot day. Apparently we have a few posters with actual JU52 experience. I would be very interested in their "real liffe" " findings.

[ATC Watcher]

A rumor in the hangars speaks about Carbon monoxide .But difficult to say if this another wild speculation or based on leaks on the first forensic tests..
I tend to go for the first option but maybe someone has more info as to where this rumor comes from .

[Walking Bird]

This what you meant?

Closeup of object, 17.00:

Can't get the resolution any better than that.

Yes, exactly. This view is apparently from south in the direction of the ridge. Distance approximately 5km.

[DRDR]

This what you meant?
Can't get the resolution any better than that.

I got the highest resolution possible, enhanced the shadows and compared the images. My result: No Ju visible in the 16:50 photo and wreck visible in the 17:00 photo. Which more or less means that we unfortunately cannot get anymore information form the webcam images.

Maybe the operator has access to more archive images. Just to be sure, I notified them...

[PaxBritannica]

Thanks, DRDR.

A question. The flight is not there at 16.50, but presumably must be fairly close, within ten miles or so, if it's down by 17.00. I've strained my eyes on the panoramic view for 16.50, but I can't pick it out anywhere. Which way would it likely approach?

[The Old Fat One]

Now we have to understand why they apparently completely lost control. I remain perplexed.

Maybe English is not your first language - I don't know- by I find your use of the word "perplexed" extremely perplexing.

I would have thought anyone with even a rudimentary knowledge of aviation could easily come up with several obvious scenarios as to how the aircraft came to the fate it did - given the circumstances we already know. Some choose to speculate, on here and elsewhere, some choose not to. I choose not to, but I would observe that some of the comments on here regarding age/experience etc, show a degree of a lack of awareness of how dynamic and variable human factors are.

Maybe that contributes to your puzzlement, maybe it does not. Either way - no offence meant, and my condolences to everybody affected by this horrible tragedy.

[EDLB]

could easily come up with several obvious scenarios as to how the aircraft came to the fate it did - given the circumstances we already know.

Since the Ju52 is a slow bird, it takes more than a simple stall to wind down in an arrow like descending crash. Normally you and especial the two experienced pilots would have recovered the bird within 500 to 1000 feet even from a power-on or power-off stall. And it did not crash in a flat spin. There is reason to believe that they had those altitude margin. So there is more to the story which hopefully will come to light in due time.

[atakacs]

Since the Ju52 is a slow bird, it takes more than a simple stall to wind down in an arrow like descending crash. Normally you and especial the two experienced pilots would have recovered the bird within 500 to 1000 feet even from a power-on or power-off stall. And it did not crash in a flat spin. There is reason to believe that they had those altitude margin. So there is more to the story which hopefully will come to light in due time.Thanks.
This indeed, more eloquently than I would have been able, summarize while I'm perplexed.
I don't see any obvious scenario where they would end up in an almost vertical dive from apparent controlled flight, with no structural damage, relatively tame weather and a very experienced crew. Sure there are some less likely situations that could think of but this remains somewhat baffling. Time will hopefully tell.

[DRDR]

Thanks, DRDR.

A question. The flight is not there at 16.50, but presumably must be fairly close, within ten miles or so, if it's down by 17.00. I've strained my eyes on the panoramic view for 16.50, but I can't pick it out anywhere. Which way would it likely approach?

I have no idea. Like you I cannot find the aircraft anywhere in the 360° (horizontal!) image taken at 16:50. So it must have been out of the rather wide view of the 22 megapixel panoramic camera system for up to 5 minutes or it must have been just above it.

By the way: The operator of the camera came back to me: They have already been approached by the authorities, but unfortunately they do not have any further images.

[G0ULI]

The aircraft was seen apparently flying normally yet a few minutes later impacted the ground vertically and partially inverted with wings and control surfaces apparently intact.

The aircraft was flying at modest airspeed speed, compared to more modern aircraft, in a mountainous area which was subject to winds measuring a significant percentage of the airspeed.

A sharp stall combined with an abrupt forward shift in the center of gravity of the aircraft accounts for the observed results. The exact details will be established by investigators, but this was an aircraft that was nearly 80 years old. It may have been in perfect condition but it was built to standards that were still being explored with single wings a novelty as an alternative to biplane wings!

A huge loss to aviation history and a great tragedy for all involved.

[FollowTheSupper]

I have no idea. Like you I cannot find the aircraft anywhere in the 360° (horizontal!) image taken at 16:50. So it must have been out of the rather wide view of the 22 megapixel panoramic camera system for up to 5 minutes or it must have been just above it.

By the way: The operator of the camera came back to me: They have already been approached by the authorities, but unfortunately they do not have any further images.
DRDR,



There is a possible aircraft approaching in the Mutta Rodunda 1650hrs panorama.

As a newcomer, I don’t think my previous attempt to upload annotated image clips succeeded, so here is a verbose verbal target indication:

Roughly SW of the camera (if the direction icon at the top right of the screen is to be believed), is a wooden post, range approx. 10m. Beyond this is a green ridge-line range approx. 4km. Go slightly left from the post along the top of the ridge-line, and there is a lone cable-car pylon. Go further left again (about the same angle), and there is a white cable-car station building. Go back half-way between the station building and the pylon, and look higher up on the image… just below the most distant (much darker) ridge-line. There appears to be an aeroplane approaching at around the same elevation as the camera (± a few 1000ft). It’s too distant to make out much (even using 500% image magnification), other than it appears to be in level flight.

Would you be able to upload a clip from this image for me, please?

[Feathers McGraw]

I think I'm right in saying that the Ju-52 passenger compartment and cockpit are not separated by any door or structure, yes?

[DRDR]

DRDR,
Would you be able to upload a clip from this image for me, please?

Sorry, I don't want to post photographs without permission from the copyright holders. You can download the complete panorama by clicking the downwards arrow at the control panel at the bottom of the screen. You can then find two flying objects, which are far away:

flying object #1:
x = 9138 y = 926

flying object #2:
x = 10049 y = 936

The left most object might fit to the estimated flightpath.

[clearedtocross]

The cockpit is a separate compartment, but there is no door between pax and crew. Pax are invited one after the other to the cockpit (standing behind pilots) and get things explained.

[Feathers McGraw]

The cockpit is a separate compartment, but there is no door between pax and crew. Pax are invited one after the other to the cockpit (standing behind pilots) and get things explained.

Thanks, that was what I thought.

[spoon84]

Thanks, DRDR.

A question. The flight is not there at 16.50, but presumably must be fairly close, within ten miles or so, if it's down by 17.00. I've strained my eyes on the panoramic view for 16.50, but I can't pick it out anywhere. Which way would it likely approach?

So the JU has go from Locarno to Dübendorf via Lodrino (LSML) than direct to Biasca - Olivone - GreinaPass - Sumvitg - Ilanz - Piz Segnas

From my calculations the impact happened at 16.57 LT (14.57 UTC), also comparing the webcame images from 16.50 and 17.00. I also look for the JU in the panoramic images but I think it was more or less abeam Illanz at 16.50 so too far away.

[Chriscom]

I think I'm right in saying that the Ju-52 passenger compartment and cockpit are not separated by any door or structure, yes?

There's a photo of the interior of a Ju-52 in the Blick article--it's no. 20 of the 32 photos in the slideshow at the bottom of the story. If that's the accident aircraft or one just like it, there's open access but through a cutout, and a normal-sized adult (certainly men) would have to hunker down to get through.

[PaxBritannica]

DRDR,



There is a possible aircraft approaching in the Mutta Rodunda 1650hrs panorama.

As a newcomer, I don’t think my previous attempt to upload annotated image clips succeeded, so here is a verbose verbal target indication:

Roughly SW of the camera (if the direction icon at the top right of the screen is to be believed), is a wooden post, range approx. 10m. Beyond this is a green ridge-line range approx. 4km. Go slightly left from the post along the top of the ridge-line, and there is a lone cable-car pylon. Go further left again (about the same angle), and there is a white cable-car station building. Go back half-way between the station building and the pylon, and look higher up on the image… just below the most distant (much darker) ridge-line. There appears to be an aeroplane approaching at around the same elevation as the camera (± a few 1000ft). It’s too distant to make out much (even using 500% image magnification), other than it appears to be in level flight.

Would you be able to upload a clip from this image for me, please?

Excellent directions, FTS. I followed them to here:

https://cimg1.ibsrv.net/gimg/www.gmforum.com-vbulletin/1000x530/panorama_view_full_662d73906fd78e20dc7172372073f747755f4315. gif

Looks like the likely path if coming from the direction of Ilanz over the ridge with the cable car line.

Still taken from Flims panorama https://laax.roundshot.com/mutta-rodunda/

[spoon84]

They probably are even over Sumvitg over there. @FollowTheSupper, incredible that you found it on that panorama pictures. Well Done!!

[Chronus]

If we accept the witness reports that the aircraft made a 180 turn before crashing, the all too important question raised is why did it make the turn. Was it for sightseeing or was it because it could no longer continue safely on its course to its destination. What we currently lack is information on any comms with the aircraft.

[PaxBritannica]

Blick published a photo taken by a passenger on the day before the crash. Shows the left wing and engine. Photo from inside plane (https://www.blick.ch/news/schweiz/letztes-foto-aus-dem-abgestuerzten-flieger-die-handys-der-toten-sind-die-wichtigsten-zeugen-id8700936.html)

[FollowTheSupper]

They probably are even over Sumvitg over there. @FollowTheSupper, incredible that you found it on that panorama pictures. Well Done!!


Thanks for the encouraging comments spoon84 and PB… I will put it down to being a spotter in a previous existence! My apologies that as a newcomer I can’t post a few simple maps and images here, which might save a thousand words.


Personally, I believe that the approaching aircraft in the panoramic image, is actually well to the East of Sumvitg, and so therefore if it is the JU52, and if it is heading towards the camera, it may have taken a more scenic, easterly-lying route than you have suggested.

My reasoning is this:

1. The ski-lift top-station at Mutta Rodunda appears in the panoramic image to be about 700m to the WNW of the camera, so the camera is probably near to the end of the rough track (which can be seen leading down from the station), perhaps at around grid 2736470mE, 1192300mN (approx. elevation 2360m). [Map coordinates can be found at the bottom of the screen on the excellent online mapping website, which was referred to in the link at post #157.]



2. The white cable-car mid-station building (referred to in post #168), which sits on top of the ridge (at a range of approx. 4km), appears to be at Crap Sogn Gion, at grid 2735550mE 1188650mN (approx. elevation 2210m).



3. There is an alp (or farmstead) vertically below the mid-station building in the image, on the near side of the valley (at a range of about 1500m). This has a building with a long, silver roof heading almost in line away from the camera, beside some slightly-red, levelled ground (or paddock?), and with a second building closer to the camera and slightly to the left, on the near side of the track. I believe that this is at Mughels, at grid 2736140mE, 1190960mN (approx. elevation 2000m). [The orientation of these buildings is clearly displayed on the map, if you zoom in fully.]

The camera and these other two positions should therefore be in a line, which passes through Piz Aul (range about 28km) on the map. The latter summit would then be the one seen in the image, immediately above the Crap Sogn Gion cable-car station. (Its prominence is supported by the fact that it is also the closest over-3000m summit to the camera, in that general direction.) The approaching aircraft is slightly to our right (i.e. to the west) of the sightline towards Piz Aul, which I would suggest puts it near to (or over) the relatively low (at 2063m) summit of Piz Mundaun (2731575mE, 1178270mN)... the north facing cliffs of which I believe can be seen below the approaching aircraft, and behind the cable-car cable. (The distance to the aircraft is very difficult to estimate, even roughly.)

Sumvitg on the other hand, is around 15km to the west of Piz Mundaun, and although the town itself is obscured in low ground, the bearing to it from the camera would pass through the cable-car top-station at Crap Masegn, at grid 2732830mE 1189390mN (approx. elevation 2470m). The latter is easily visible in the image, well to the right of the wooden post (also referred to in #168), where the wide gap in the distant skyline marks the course of the Upper Rhein valley.




Although I live roughly 100km SW from the crash site, I distinctly heard the drone of a JU52 passing on the previous day. The sound is fairly rare, but not unknown around here. Perhaps it was the same aircraft taking a different route on the outbound leg… or maybe it was a separate trip by a sister aircraft. Unusually, I was so busy that I did not interrupt my work, in order to pop outside and savour its fly-past.

I should therefore strongly echo G0ULI’s recent comments about loss and tragedy, which somehow didn’t appear as intended at the end of my earlier post.

[EDML]

First of all the published picture was not taken on the accident flight.

Looking at the picture I don't see any problems. They are not even close to the mountains on the side. That is very relaxed mountain flying.

[spoon84]

Which picture do you talk about? The one posted by PaxBritannica or by myself taken from the Blick.ch?

Both are taken the 4th August and shows the Ju-52 (HB-HOT) during its last flight. The Panorama picture can't be sure at 100% but likely.

Regarding the picture which stated the last turn of the Ju before the crash, I read a lot of speculations regarding a fake picture or that it's the flight towards Locarno the day before, well please read the article in the Blick first: https://www.blick.ch/news/schweiz/augenzeuge-sah-den-ju-52-absturz-am-piz-segnas-es-war-ein-bild-des-grauens-id8700276.html

Second the flight from DUB to LOC was done in the morning of the 3rd August arriving in Locarno at 10.10 LT and the route was via Grindelwald, Aletsch Glacier, Gothard and Leventina Valley down to Locarno, so it didn't pass trough Segnespass.
https://cimg8.ibsrv.net/gimg/www.gmforum.com-vbulletin/1655x823/ju52_de8047e9dd3907c9062387d1dffc9aa3ca70dd7b.jpg

[Volume]

Normally you and especial the two experienced pilots would have recovered the bird within 500 to 1000 feet even from a power-on or power-off stall. And it did not crash in a flat spin. There is reason to believe that they had those altitude margin.
Spinning is a quite complicated "maneurvre". It takes an initiation phase before you are in a stable spin and terms like "flat spin" make sense. This phase may already use up 1000 feet in a large aeroplane. During the first phase of a spin it is not unusual to fly inverted or in a steep dive before a stable equilibrum between all erodynamic and dynamic forces is established. Check this picture (https://www.weser-kurier.de/cms_media/module_img/2756/1378038_1_articlefancybox_53e3b9039fffc.jpg) of the early entry phase into a (fatal) spin for example. In the following second the aircraft will be in an almost vertical dive still acellerating the rotational speed before entering a stable spin after somr 5-10 seconds. If you run out of altitude at that moment, the result looks like in this picture (http://i.ytimg.com/vi/a3VExTKMl_4/maxresdefault.jpg). Which matches the Junkers wreakage quite well.
The recovery altitude given in the handbooks is between starting countermeasures in a stable spin and the full recovery. The altitude between stall and stable spin can not be given, as there are too many different scenarios how to enter it, for example the actual bank angle at the time of the stall.

anyone with even a rudimentary knowledge of aviation could easily come up with several obvious scenarios as to how the aircraft came to the fate it did
For me there are basically two realistic scenarios, stall and spin or elevator control (elevator trim) failure. Although people talk about "high speed" I think the low fragmentation of the wreakage does not confirm that, Impact speed must have been well below 200 km/h (compare it with the oskosh mustang, where only small fragments were left and the aircraft lierally "exploded" at impact purely due to kinetic energy). So for me the stall and spin theory, linked to relatively slow inpact speed, makes more sense. Although a stable spin has never been established due to low altitude, so it is stall and spin entry... A former BAZL expert thinks the same.

The sad aspect is, in this case the investigation has nothing to find. The wreakage will tell no story, there will be no "smoking gun". There will be no corrective action. It happened a thousand times before, it will always happen.

[GeeRam]

Spinning is a quite complicated "maneurvre". It takes an initiation phase before you are in a stable spin and terms like "flat spin" make sense. This phase may already use up 1000 feet in a large aeroplane. During the first phase of a spin it is not unusual to fly inverted or in a steep dive before a stable equilibrum between all erodynamic and dynamic forces is established. Check this picture (https://www.weser-kurier.de/cms_media/module_img/2756/1378038_1_articlefancybox_53e3b9039fffc.jpg) of the early entry phase into a (fatal) spin for example. In the following second the aircraft will be in an almost vertical dive still acellerating the rotational speed before entering a stable spin after somr 5-10 seconds. If you run out of altitude at that moment, the result looks like in this picture (http://i.ytimg.com/vi/a3VExTKMl_4/maxresdefault.jpg). Which matches the Junkers wreakage quite well.


The video of the seaplane crash into the Swan River last year is worth looking at if not seen before........

http://www.youtube.com/watch?v=e5c2UX2Na_E&list=PL_r-JHAP-6mMsQZZM0keYrf3jV9pG5VSc

.

[Bend alot]

The video of the seaplane crash into the Swan River last year is worth looking at if not seen before........

http://www.youtube.com/watch?v=e5c2UX2Na_E&list=PL_r-JHAP-6mMsQZZM0keYrf3jV9pG5VSc

.
Trying to find the final report on that crash to see what went wrong.

Seems to have a bit of evidence around unlike this crash.

[MadMax9]

Following FollowTheSupper #168 and PaxBritannica #175:

The spotted aircraft in #168, picture in #175, is in the middle line of view to Piz Aul (left), 28km from panorama camera and Piz Mendel (right), 37km. Both mountains are 16km apart, but at the distance of Piz Aul the view lines have spread of 12km, in the picture 450 pixel

The aircraft in the middle has between 4-6 pixel for a 30m wingspan (assuming it is flying towards the camera/Piz Segnas). As the dark pixels are much wider than high, as can be expected for a airplane flying stable shot from the front, I would assume it is not an camera/optics/resolution artefact giving that size/shape of the dark spot.

Numbers above calculate to a distance between 5.3 to 8.1km to the panorama camera, which is about double distance to the cable on top of the ridge in between. The shortest distance to the crash site is then between 8.5 and 11km, measured from map. Calculating with a speed of like 180km/h this would be just between 1.5 to 2.6 minutes.

If the camera operator can further specify the exact time when the "16:50" picture was really taken, and if the exact time of picture in #157 is known or at least time of crash (16:57 ?), this would allow a sharper calculation of average speed in the approach, but accuracy not better than 20% (from distance and assuming straight-line flight) and still subject to time difference accuracy.

Of course the pixels don't need to be the JU52, but specifically the direction and distance are very reasonable.

[MadMax9]

Analyzing picture in #151 with photogrammetric calculations (just in excel):

From 8 different topographic marks on the photo and using lat, lon, height values of those marks from WGS84 system in the map referenced in #157 the position/direction of the camera can be derived by mean-squared-error method:
Camera 46.902233 N, 9.224865255 E, 2639m Az 133.51° Elev 6.7°
This is close to the Segnespass mountain lodge, but 12 m higher. Camera direction therefore is SE with 6.7° slightly upwards, 5° rotated clockwise.

The location of the plane shadow is where the line of sight crosses the terrain.
Shadow: 46.8987249855829 N, 9.23385 E, 2541m, distance from camera 792m

Direction of Sun at position of shadow Sat Aug 4, 16:50 local time can be derived rom several sites like sunearthtools. Of course this is the direction to the plane as well to create the shadow.
Sun: Az 252.88°, Elev 38.3°

Last element is to find the point were sun-shadow line crosses with line-of-sight to the plane derived from the photo:
Plane: 46.8981223562367 N, 9.2309869436985 E, 2721m, distance from camera 657m, 82m above camera
Actually the two lines are not crossing exactly, but have 15 pixel distance, which is half the planes size, likely due to sum of all small inaccuracies, which we have to be aware of.

The terrain height at the planes position is measured again from the map as 2473m. Thus the Ju52 has is in the moment of photo taken an calculated AGL of 248m.

BTW, the height of 2721m is about 100m above the lowest parts of the Segnespass ...

[MadMax9]

Actually, the calculated position would be just 200m SE from the crash site

[FollowTheSupper]

MadMax9,



Many thanks for taking the trouble to post a range / time analysis. However, I suspect that the peak which is 450 pixels to the right of Piz Aul in the panoramic image... is actually Piz Terri, and not Piz Mendel. The latter is much further away, and by my reckoning from the map should appear close to a cable-car pylon on the ridge... not the previously-mentioned one (post #168), but the one which stands to the right of the wooden post… even allowing for ±100m uncertainty in the actual camera position. (Also, if you do an internet search for Piz Terri, there is an excellent summit photo taken from a slightly more southerly position, which can be matched well to the summit which appears in the panoramic image.)



As the bearing from the panoramic camera to Piz Terri is closer to the bearing to Piz Aul (than is the bearing you have proposed to Piz Mendel), then that would place the aircraft further away.



In any case, a safer analysis (avoiding any debate about summits!) might be to note that the full 360° panoramic image width is covered by 15707 pixels, making 0.0229° per pixel. Taking the aircraft width as 4 pixels, and assuming that the aircraft is approaching the camera (I agree with you that the lack of height or asymmetry in the dark pixel distribution supports this orientation), then a 30m wingspan would subtend 4 pixels at a range of around 18.7km (or 15km if the wingspan is taken as being spread over 5 pixels). This would then place the aircraft over (or slightly beyond) the Piz Mundaun feature, i.e. about 5km SW of the town of Ilanz.

Also, I suspect that 180km/hr as a groundspeed might be a bit optimistic for these aircraft – particularly on a leisurely sight-seeing flight, the appeal of which would surely be more about the flight than a timely arrival. (Indeed, when I see them flying past my house, their progress is usually – shall we say – somewhat unhurried!) So, if the dark pixels are indeed the JU52 around Piz Mundaun, then it could perhaps be 7 to 8 minutes after the image was captured, before it reached the Segnespass area.

[Alpine Flyer]

The sad aspect is, in this case the investigation has nothing to find. The wreakage will tell no story, there will be no "smoking gun". There will be no corrective action. It happened a thousand times before, it will always happen.

Inspection of the engines and fuselage will show whether there were any engine/propeller/structural issues and analysis of surviving video recordings might help to understand the flight path and at least some of the flight dynamics. There must have been at least half a dozen cameras running in that airplane. There was one in the Embraer in Durango a couple of days ago and that was a normal airline flight without much to see outside, so there must have been more on a scenic flight with an Oldtimer passing spectacular landscape.

[ATC Watcher]

Originally Posted by Volume https://www.pprune.org/images/buttons/viewpost.gif (https://www.pprune.org/rumours-news/611836-4th-aug-2018-junkers-ju52-crashed-switzerland-10.html#post10218903)
The sad aspect is, in this case the investigation has nothing to find.
If the aircraft was FLARM equipped ( it should be ) and if the device was not severely damaged by the impact , the flight can be downloaded and the final minutes analysis could give some clues

[clearedtocross]

None of the JU-AIR aircraft were FLARM equipped according to the Bundesamt fuer Zivilluftfahrt - the Swiss Civil aviation authority. This is difficult to understand by the way, particularly because they often operated in a region with a lot of glider activity. And the ATC radar of Zurich does not cover the crash region at this altitude. There's a chance that the military primary radar might have picked up some signals, but certainly not with a frequency of 1 Hz like the Flarm.
However, they might have carried a GPS device that recorded the flight.

[MadMax9]

FollowTheSupper,

agree to your corrections regarding larger distance from Mutta Rodunda.

Regarding the calculated position of the JU52 from the picture #157 (my post #186) it would be only 12 to 16 seconds time from there to fly to the Segnespass (657m distance to the photographer close to the lodge), subject to speed. But not much time to gain significant height with climb rate of maybe 2m/s when fully loaded at higher altitude/high temperature. Maybe somebody can calculate that figure. A northerly head wind coming over the ridge and going down the valley with conservative 30km/h = 8m/s would further reduce the effective climb rate a lot.

Actually the crash site is located less than 50m north of that straight line, which would fit to the left bank attitude visible in the last photo. And with only 200m distance from the last photo position to crash site this gives just 4-5 seconds remaining bevor the tragedy occurs. This does not tell us if the intended flight path was to still go over the pass with a low margin, or into a 180° turn. However, with the JU52 position at that time not far from the middle of the valley, the turn radius would have to be less than around 300m.

You can find a map with positions and view lines if you copy this link to swiss map: s.geo.admin.ch/7c4ffa5367

[atakacs]

N
This is difficult to understand by the way, particularly because they often operated in a region with a lot of glider activity.
Indeed surprising.
One less source if information :(

[sycamore]

At 180kph/97kts TAS,30* BANK,,radius-1500ft; rate 6.5*/sec.
At 40*bank,,radius 1100ft;rate 9.5*.sec.
At 220kph/120ktsTAS,30*bank,radius 2000ft, rate 5.5*/sec..
At 40*bank,radius 1500 ft., rate 8*/sec...
close approximation..

[jimjim1]

MadMax9

Thanks for your analysis.

Just to let you know that post numbers can change with time and your posts may be more difficult to follow some time in the future. I assume if posts are deleted then the numbers will get re-calculated. I also imagine that if a user deletes their account that all their posts will disappear. I have observed incorrect post references many times on pprune so I think that posts get deleted quite frequently.

I would guess that the "(permalink)" link beside the post number is intended to be used to circumvent this issue.

Example permalink to #192:-
https://www.pprune.org/rumours-news/611836-4th-aug-2018-junkers-ju52-crashed-switzerland-10.html#post10220187

"https://www.pprune.org/rumours-news/611836-4th-aug-2018-junkers-ju52-crashed-switzerland-10.html#post10220187"

[blind pew]

https://youtu.be/HosF_xKeeGE
A straight spin in a K6 glider from st remy last year. Note the bank angle.
I found myself inverted in a Beech baron in 1971 from a clean power off stall. The aircraft flicked completely inverted but with very little pitch down.
I similarly found myself inverted whilst instructing mountain flying in a grob glider from the cape gliding club. Figures of 8 below 200ft and with a bang caused by the shear from a thermal rising up the quarry face again inverted with nose more or less on the horizon.
Steve Fossett got into the lee and I've had quite a few surprises in the last 20 years flying in the mountains.
MY local paragliding wind reporter had a gust last week exceeding 140kph.
The guys I knew who flew Tante Ju were ex SR captain's and military..another ball game

[atakacs]

It could indeed be as simple as a strong unexpected gust in marginal conditions. I would still be surprised that those guys would have put themselves in such a corner.
That's why I'm trying to get real liffe performance info for a JU-52... It is really hard to gauge how close to the limits they might have been.

[clearedtocross]

The "NZZ am Sonntag" today printed an article with the headlines "Die JU-52 flog an ihrer Leistungsgrenze" which translates as "the JU was flying at its limits", a statement I made longtime ago in this forum and was bashed for it by people who thought to know better. The author of the article, aviation journalist Mr. Sepp Moser suggested that a vapour lock might have caused a coughing of one of the engines which made the pilots turn away rather abruptly to avoid rising terrain. Considering the fact that the aircraft was parked in Locarno under a blazing sun until 16:00 and that the Junkers has no gravity fuel feed, its a possible scenario, even more so because booster pumps should not be used at altitude because they make the engines run too fat.

[aerobat77]

of course speculation but i guess there is not much secrets in this tragedy .

probably they realized they do not have the performance to make it over the mountains infront so they tried a sharp 180 deg turn to save the day . during the turn , loosing more and more speed trying to maintain altitude , one wing stalled and they went down like a rock without being able to recover .

investigation surely will focus the reason for the lack of performance .

( just to heavy on this hot day or engine problems )

i guess thats all .

[EDLB]

Don’t believe that. With a slow plane with a 18000 feet(ish) ceiling, you can and will circle all day on the mountainside with upwinds, until you have enough margin to make it over the pass. On that CAVOC day you can make that judgement only with visual clues. That they run out of performance only if they had engine troubles. And even then you let not get it into a corner but start a fly or glide to some decent emergency landing area early. With two experiences pilots that should be no task overload. One flies the airplane and the other deals with the technical problem. With such a relative low tech bird with mechanical control surfaces should be not much problem. I am sure there is more to the story and that will come out.

[clearedtocross]

EDLB Dream on about your ceiling of 18'000 ft. With the downgraded engines (500 instead of 750 hp) it would be difficult to coax it over 12'000 ft even on a standard day. By the way, we had 3 fatal accidents in Switzerland in the last 3 weeks, all with the same pattern: hot, high, unable to get over the next obstacle, spun into the deck. 28 dead. Really sad. Heat is a killer even if it shows a pretty face compared with other perils for VFR flights like bad visibility or high winds.

[EDLB]

So you claim that the standard service ceiling of a slow 1500Hp plane is 12000 feet and they offer 17 pax flights in the Alps?
IMHO the performance of that Ju52 is a bit better than a standard C172.
If you start hot and high then the performance is worst right after take off. As higher you climb, as cooler gets the air improving performance of your props, wing and engine. Sure the air gets thinner and counteracts this a bit but to my experience if you make it over the fence hot and high then you make it over 14000feet after one hour.
They where almost an hour into their flight so on fuel lighter than on take off.
You do not fly the plane on the backside of its performance curve without dire circumstances. And as long they fly IAS with decent margin, they should not fall out of the sky. They did, so the investigation will hopefully figure out what those dire circumstances where.

[aerobat77]

edlb ..in a life as a pilot all odds may be against you . you want to fulfill the mission and you did the trip many times before . that day a glowing heat covers the alps and just that day the plane is fully booked , the passengers have much baggage , you are very heavy. you depart with a bad feeling but you want to fullfill the mission , the heat also does not improve your brain and common sense. over the alps you realize you are at the edge of performance but you want to continue - more and more trading speed for climb . in the last minute you see that this time you will really not make the mountains and in panic - being already critically low on speed - you make a sharp 180 deg turn to avoid crashing into the mountains . during the turn a wing stalls snd seconds later you hit the elevated bottom .

thats what happened i guess , they simply asked their ju52 for something she was not able to deliver at that day with that heat and that load .just few passengers less or a little colder athmosphere and that would end without an issue or media coverage .

[EDLB]

Folks you don‘t make it to the age of 62 and 63 as captain if you think like this. Darwin will have sorted you out much earlier.

[atakacs]

I'd be really interrested about "real liffe" performance data for those JU-52...
Also are they comparable (I understand they had 3 planes...)?

[RoyHudd]

Some of the worst captains in all cultures are over 60 years old.. And put 2 old captains flying together, well that is often not good. Ask any commercial pilot.

Furthermore operating an old Junkers at high altitudes in the high mountains, fully loaded, is not intelligent. It is risky. Given that one must assume a failure at critical circumstances, be it power plant or even flying controls.

The CH folk do not have the best safety record either, be they pilots or ATC. There appears to be some complacency here, sadly unfounded.

[Standby Scum]

I think the eldest son in a Swiss family isn't allowed to fly in their Air Force, for a very good reason.

[atakacs]

Some of the worst captains in all cultures are over 60 years old.. And put 2 old captains flying together, well that is often not good. Ask any commercial pilot.

Furthermore operating an old Junkers at high altitudes in the high mountains, fully loaded, is not intelligent. It is risky. Given that one must assume a failure at critical circumstances, be it power plant or even flying
You might be on something here. Unfortunately it is very hard to get a sense of how close to the limits they were. I'm sure this will be covered in the investigation report.

As a matter of fact when is the preliminary due?

[Dora-9]

Some of the worst captains in all cultures are over 60 years old.. And put 2 old captains flying together, well that is often not good. Ask any commercial pilot.


That's tosh. Sounds like RoyHudd is a bitter younger FO to me.

[atakacs]

I've seen operations where they actively tried to avoid such pairing. I guess they had their reasons....

[Dora-9]

I think the key phrase is "some of the...". Both major airline operators that I flew for rarely flew two captains together on a line flight (for obvious cost reasons) although I've never seen or heard of a two captains restriction. There could be lots of reasons that your operator, atakacks, actively avoided this, not necessarily because they're all megalomaniacs - as I think that you and RoyHudd are implying. Let's just wait for the report?

[andrasz]

There could be lots of reasons that your operator, atakacks, actively avoided this, not necessarily because they're all megalomaniacs - as I think that you and RoyHudd are implying.
At the outfit I used to be with, while there was no formal policy, it was accepted practice to avoid pairing senior captains because of the increased risk of complacency. This comes straight from the mouth of the horse, the Flight Ops Director was one of them, and he had FOQA data to back this up. (BTW the Pretoria CV-340 also had two senior captains up front).

[Pearly White]

That's tosh. Sounds like RoyHudd is a bitter younger FO to me.
Some very simply-conducted research of RoyHudd's previous posts and threads started would have quickly eliminated that theory.

Crusty industry veteran who doesn't suffer fools gladly, more like.

[ATC Watcher]

The CH folk do not have the best safety record either, be they pilots or ATC. .
Can you please elaborate on what you base your statement on ? Sounds a bit harsh I would say.
On the 2 Capt theory , yes unfortunately there, the data support this . One (of many) that comes to my mind is the one and only TAP accident (in Funchal 1977) had 2 capt on board and decisions were impaired . that accident led to lots of changes in Funchal ops and in crew pairing .

[meleagertoo]

It never ceases to amaze me that even after 30+ years of human factors training in which human fallibility is so closely examined, additional to decades of global accident statistics that show conclusively that by far the biggest single cause of accidents is broadly dscribed as "pilot error" that so many pople are so reluctant to accept the likelyhood that this accident was simply what it appears to be. Mishandling.
There have been dozens of accidents reported in this forum over the years that have attracted the same old automatic responses, "A 60 year old commerecial pilot would never do that!", "He was an ex military pilot, he'd never make such a basic error", "I knew him and I know he'd never make such a mistake" "he was a brilliant pilot and he'd never -"etc.etc.etc. But every time he did, time and again it turns out that's exactly what they did. I realise it's difficult to accept that even such experienced pilots as this can make such a basic error but experience, history and statistics prove that they do, and regularly. Sure, HF applies here too, acceptance of the ability of experienced pilots to make very basic errors relies on our acceptance of our own fallibility, something none of us like to admit to. Thrashing around trying to invent ever more ulikely scenarios (elevator trim failure was one) when a heavily loaded, underpowered vintage aircraft tries to make a downwind turn in a mountain valley just below a ridge at high density altitude and falls inverted from the sky suggests to me that the lessons of HF are still not as ingrained as they might be, though I recognise that there are a lot of expert spotters/spectators etc here vs. pilots who have actually studied that subject. Sad as it seems it appears that these guys got themselves too far into a narrowing hole and tried just a bit too hard to turn out of it, and got bitten by 1930's stall habits. What seems more important here is not so much the what as the why?

There has been considerable discussion about the stall characteristics (esp. power on) of the DC3/C47 following the CAF's recent accident in which many have attested to that type's viscious stall habits. Tante Ju was from a design era pre C47 and would very likely behave in much the same abrupt manner in an aggravated power-on stall. We saw the Australian Mallard make a simiar manoeuvre with similar results. Yes, of course there's a tiny possibility that the inside knurled flange-bracket went "ping" but all the evidence points elsewhere, and whatsmore to the same place. But that's playing double jeopardy, isn't it? At the very point in a flight where every aviator says "Bloody hell, they're really asking for trouble doing that" something completely unexpected and invisible yet critical chooses that very instant to break. It isn't really a credible scenario. (viz the Shoreham accident. Page after page of fanciful speculative failures when all the time the duck was sitting there patiently quacking away)

Guys, though it isn't yet proven (and never will be as they 99.9% for certain won't find anything significant in the mechanical investigation) this case has all the attributes of the duck analogy. Looks like, sounds like, swims like. Is.

I think we'd sometimes do better to recognise and accept the weight of the obvious in reaching our local (as opposed to the investigators') conclusion rather than trying to invent fanciful "balancing" arguments where no shred of evidence nor requirement for them for them exists.

We have had a report (my previous post somewhere above) that on a previous flight the aircraft was apparently flown in a more "sporting" manner than the pax liked such that the pilots had to be asked to tone it down and though that report is anecdotal and a one-off (so far) it may well indicate an operational style that had developed. I too find it hard to believe that professional pilots would throw pax around so much they got sick and had tp be told to knock it off but apparently they did. If that does prove to be the case one can only wonder whether it was a one-off or not, or had other less than prudent habits attended the operation not just in flying but in the field of performance and loading perhaps? If so it wouldn't be the first time professional pilots, removed from the straitjacket of airline ops found themselves in a relaxed little fun operation where they could cut loose a bit. And came to grief because of it. After all, that's just human nature (factors).

That is where the bulk of the investigation will centre I suspect.

[Toryu]

Great post, mealeagertoo!

Mountain-slopes all over the world are littered with mangled wreckages that have been put there by captains that should have ben too experienced to let this happen.
In fact, it's exactly this attitude that is the first hole in the cheese...

[clearedtocross]

If you start hot and high then the performance is worst right after take off. As higher you climb, as cooler gets the air improving performance of your props, wing and engine. Sure the air gets thinner and counteracts this a bit but to my experience if you make it over the fence hot and high then you make it over 14000feet after one hour.It's against our environmental protection laws to litter our mountains with guys and their aircraft who believe they may pass any obstacle once they have made the fence. .

[hans brinker]

It never ceases to amaze me that even after 30+ years of human factors training in which human fallibility is so closely examined, additional to decades of global accident statistics that show conclusively that by far the biggest single cause of accidents is broadly dscribed as "pilot error" that so many pople are so reluctant to accept the likelyhood that this accident was simply what it appears to be. Mishandling.
There have been dozens of accidents reported in this forum over the years that have attracted the same old automatic responses, "A 60 year old commerecial pilot would never do that!", "He was an ex military pilot, he'd never make such a basic error", "I knew him and I know he'd never make such a mistake" "he was a brilliant pilot and he'd never -"etc.etc.etc. But every time he did, time and again it turns out that's exactly what they did. I realise it's difficult to accept that even such experienced pilots as this can make such a basic error but experience, history and statistics prove that they do, and regularly. Sure, HF applies here too, acceptance of the ability of experienced pilots to make very basic errors relies on our acceptance of our own fallibility, something none of us like to admit to. Thrashing around trying to invent ever more ulikely scenarios (elevator trim failure was one) when a heavily loaded, underpowered vintage aircraft tries to make a downwind turn in a mountain valley just below a ridge at high density altitude and falls inverted from the sky suggests to me that the lessons of HF are still not as ingrained as they might be, though I recognise that there are a lot of expert spotters/spectators etc here vs. pilots who have actually studied that subject. Sad as it seems it appears that these guys got themselves too far into a narrowing hole and tried just a bit too hard to turn out of it, and got bitten by 1930's stall habits. What seems more important here is not so much the what as the why?

There has been considerable discussion about the stall characteristics (esp. power on) of the DC3/C47 following the CAF's recent accident in which many have attested to that type's viscious stall habits. Tante Ju was from a design era pre C47 and would very likely behave in much the same abrupt manner in an aggravated power-on stall. We saw the Australian Mallard make a simiar manoeuvre with similar results. Yes, of course there's a tiny possibility that the inside knurled flange-bracket went "ping" but all the evidence points elsewhere, and whatsmore to the same place. But that's playing double jeopardy, isn't it? At the very point in a flight where every aviator says "Bloody hell, they're really asking for trouble doing that" something completely unexpected and invisible yet critical chooses that very instant to break. It isn't really a credible scenario. (viz the Shoreham accident. Page after page of fanciful speculative failures when all the time the duck was sitting there patiently quacking away)

Guys, though it isn't yet proven (and never will be as they 99.9% for certain won't find anything significant in the mechanical investigation) this case has all the attributes of the duck analogy. Looks like, sounds like, swims like. Is.

I think we'd sometimes do better to recognise and accept the weight of the obvious in reaching our local (as opposed to the investigators') conclusion rather than trying to invent fanciful "balancing" arguments where no shred of evidence nor requirement for them for them exists.

We have had a report (my previous post somewhere above) that on a previous flight the aircraft was apparently flown in a more "sporting" manner than the pax liked such that the pilots had to be asked to tone it down and though that report is anecdotal and a one-off (so far) it may well indicate an operational style that had developed. I too find it hard to believe that professional pilots would throw pax around so much they got sick and had tp be told to knock it off but apparently they did. If that does prove to be the case one can only wonder whether it was a one-off or not, or had other less than prudent habits attended the operation not just in flying but in the field of performance and loading perhaps? If so it wouldn't be the first time professional pilots, removed from the straitjacket of airline ops found themselves in a relaxed little fun operation where they could cut loose a bit. And came to grief because of it. After all, that's just human nature (factors).

That is where the bulk of the investigation will centre I suspect.


Great post, sadly totally made irrelevant by the words " downwind turn". There are downdrafts downwind of mountain ridges, but there is no such thing as a downwind turn.

[gearlever]

WOW, very impressive to learn some know already what actually happened.

[meleagertoo]

but there is no such thing as a downwind turn.

Eh???
Not many people know that, my friend, and even if you take issue with the terminology (but why? It is a common enough expresson) everyone knows what is meant by it and the significance of it in this case. Quite how that one petty cavil renders an entire post "totally made irrelevant" (ugh!) is known only to you pal - but it doesn't say much for your CRM, tolerance or powers of logic and judgement does it?

Nul points for a pointless, irrelevant snipe.

gearlever - do spill the beans - who "knows exactly what actually happened"? and what was it? I'm impressed you "know" too. Hadn't realised the case was closed and hadn't read any post so far revealing it.
Or could it be you read my post so so carelessley that you took it to be a statement of facts rather than the clearly stated hypothesis based on probability and likleyhood that was repeated so many times specifically so lazy people who don't bother to read posts properly might not jump to conclusions and mistake it for something else.
Human factors again?

[RenegadeMan]

Eh???
Not many people know that, my friend, and even if you take issue with the terminology (but why? It is a common enough expresson) everyone knows what is meant by it and the significance of it in this case. Quite how that one petty cavil renders an entire post "utterly irrelevant" is known only to you pal - but it doesn't say much for your CRM, tolerance or powers of logic and judgement does it?

Nul points for a pointless, irrelevant snipe.

Very much appreciated your post too meleagertoo (and I didn't think any of it "irrelevant" by the mention of a downwind turn). I think this person is just exercising the usual knee-jerk black & white judgement reaction to the possibility that in using the term you're indicating you're from that die-hard aviation fraternity that swears by the belief an aircraft behaves differently (and has differing stall speeds) depending on whether you're turning into the wind or away from it. There is of course an ongoing debate with members of this fraternity where some will absolutely hang-on to this notion that an upwind turn "can save you" in circumstances where you're close to stalling whereas an equivalent downwind turn can be your undoing. What's missed in these discussions again and again is that these turns can only be termed "upwind" and "downwind" when considered in regards to reference against the terrain the aircraft is flying over and it is when a pilot falls for the trap of attempting to tighten a turn because of the perceived overshoot with reference to the ground or terrain that a "downwind turn" can be so fraught with danger.

And (from what I can assess with the obvious experience and knowledge you've presented in your post) it's this phenomena you're talking about; an aircraft close to the edge of its performance envelop in high density altitude conditions boxed in by rising terrain where a downwind turn will have the pilots likely overshooting with the radius of the turn bigger than expected resulting in them (potentially and unwittingly) pulling it tighter and into a stall. This is an accident scenario all too common, with one of the more obvious ones being where pilots stall during the turn from base onto final when dealing with a strong crosswind. They start overshooting during the turn because they didn't allow for the wind behind them and in the ensuing over-banking stall and spiral in.

The human factors you've written about and the complacency that can set in with very experienced high-hours flight crew is all too likely to have been the major contributing factor in this accident. I appreciate how you've articulated this.

[His dudeness]

The human factors you've written about and the complacency that can set in with very experienced high-hours flight crew is all too likely to have been the major contributing factor in this accident. I appreciate how you've articulated this.

And how exactly, given the info available, have you reached this conclusion ?

[atakacs]

Sorry to start a new thread but the previous has been locked down for some reason (mods: fell free to append to existing).

The OFAC has released (https://www.admin.ch/gov/fr/accueil/documentation/communiques.msg-id-71843.html)a few restriction for JU-Air effective immediately (sorry only found the French version). They require

flight level above legal minima (sorry no specifics given)
GPS based flight recording to retrace past routes
measures (again no specifics) insuring that passengers can't move in the cabin during flight


Although nothing explicit one can read between the lines...

[Maisk Rotum]

There are some eerily similar circumstances between this crash and the Convair in SA. Highly experienced pilots allowing risky behaviour they otherwise would never allow in their professional worlds.

[NutLoose]

https://www.sust.admin.ch/inhalte/AV-berichte/HB-HOT.pdf

Thread was locked so couldn't add it.



''The Swiss Transportation Safety Investigation Board (STSB) issued a preliminary report on the August 4 accident involving a historic Junkers Ju-52/3m accident.

The Ju-52 aircraft, operated by Ju-Air, crashed into the western slope of Piz Segnas, Switzerland, at an elevation of 2540 m. All 17 passengers and three crew members were killed.

The brief report stated that the aircraft flew on a northeasterly course into the basin southwest of Piz Segnas. Towards the north end of the basin, it began a left turn, which developed into a descending spiral trajectory. A short time later, the aircraft collided with the ground almost vertically and at high speed.''


https://news.aviation-safety.net/2018/08/21/stsb-junkers-ju-52-entered-a-spin-while-making-a-turn-in-a-mountain-basin/

[atakacs]

Very light preliminary I'd say...

The two other planes are flying again since last weekend. They had only few cancelations of reserved flights. Out of the 25 pilots pool one has demanded some time out.

[Less Hair]

BAZL ordered doubled minimum altitudes, GPS position logging for all flights and passengers seated and belted during all flights all the time. It's good that they can continue flying.

[Onceapilot]

Here is a translation of the linked Swiss report dated 15Aug:

An investigation.
Place, date and time: 500 m southeast of Segnaspass (GR), August 4, 2018, 16:56 LT
Aircraft
Enrolment: HB-Hot
Samples: Junkers aircraft and engine Works AG, Ju-52/3m G4E
Holder: Association of Friends of the Swiss Air Force (VFL),
Via Landstrasse 271, 8600 Dübendorf
Owner: Swiss Air Force, P.O. Box 1072, 8600 Dübendorf
Pilots: 2
Cabin Crew: 1
Passengers: 17
Flight:
Flight rules: Visual flight Rules-VFR
Mode of operation: lucrative
Begin of departure: Locarno (LSZL)
Destination: Dübendorf (LSMD)
Damage:
Crew: 3 fatally injured
Passengers: 17 fatally injured
Third parties: None
Aircraft: Destroyed
Third-party damage: low Floor damage
Short Description: The plane flew on a northeast course in the basin Southwest
of the Piz Segnas. Against the northern end of the basin
It started a left turn that turned into a spiral trajectory
Developed against the bottom. A short time later, the plane collided almost
perpendicular to the terrain.

[Onceapilot]

The report seems to make a few things more established. I note that there is no reference to "high speed". Unsurprisingly, there is no real analysis here.

OAP

[Onceapilot]

A report has been issued by the Swiss authorities about the accident, including details about corrosion in parts of the airframe. I believe that operation of the type has been stopped at the present time. Obviously, a better translation of the document will help further understanding.

OAP

[Onceapilot]

This document is an interim accident report but, I am afraid I cannot post a translation. I will attempt to post the internet address.
https://www.sust.admin.ch/inhalte/AV-berichte/HB-HOT_ZB_D.pdf

OAP

[ATC Watcher]

Sad story . This interim report basically does not talk about the accident itself but about the corrosion found on the aircraft ,and despite the conclusion that the corrosion had nothing to do with the accident grounded the 2 other aircraft ;
11. Airworthiness certificate of the HB-HOP aircraft of 7 June 2007
will be withdrawn from now and until further notice
12. Airworthiness certificate of the HB-HOS aircraft of 7 June 2007
will be withdrawn from now and until further notice.
13. The aircraft HB-HOP and HB-HOS may with immediate effect
no longer be put into circulation.

[cappt]

My understanding with help from google.
Significant shortcomings in maintenance, management and parts inventory. Exfoliation corrosion in floor/wing attach area. Had cylinders salvaged from 1941 wreck? Engine two/three new cam discs found with damage, same in sister ships. Fuel/oil lines 30 years old!
Poor condition how ever, not related to the accident.

[Onceapilot]

Thanks ATC and cappt, an "interim report".

OAP

[clearedtocross]

My understanding with help from google.
Significant shortcomings in maintenance, management and parts inventory. Exfoliation corrosion in floor/wing attach area. Had cylinders salvaged from 1941 wreck? Engine two/three new cam discs found with damage, same in sister ships. Fuel/oil lines 30 years old!
Poor condition how ever, not related to the accident.https://www.pprune.org/images/statusicon/user_online.gif https://www.pprune.org/images/buttons/report.gif (https://www.pprune.org/report.php?p=10315919) https://www.pprune.org/images/buttons/quote.gif (https://www.pprune.org/newreply.php?do=newreply&p=10315919)
Quite correct, cappt!
The intermediate report contains some more interesting details. Temperature was ISA + 16 and all engines were delivering power. The report from the accident investigation branch is not only rather damning for operator and maintenance, but also for the oversight of the Swiss Federal Office of Civil Aviation. They (FOCA) claim they could not have seen all the rotten stuff. Well, looking for instance at the picture of the fuel lines, its difficult to imagine that even a brief inspection could overlook that. Inspections nowadays are all about forms, stamps and signatures, the hardware only gets a brief glimpse. Not helpful is also the fact that operator, maintenance and engine repairs are all controlled by the same persons. And the boss now claims that the corrosion set in only after the accident.....

[PFR]

Is there no English translation available for this Report?

[DaveReidUK]

Is there no English translation available for this Report?

No, there is no official English version.

[Onceapilot]

Is there no English translation available for this Report?

Not so far. You can copy and post the text into bing translate, page by page. The result is pidgin but, understandable. I have read that: " It crashed, 20 killed, ISA+16, no fire, unsurvivable. Subsequently, they have found corrosion, poor repairs, unregulated parts, unsegregated stock, all engines working at impact, fuel on board. The Flying permits for the other two aircraft are withdrawn. The full report will address all aspects of the accident".
It is sad reading. However, there is no attempt to describe the cause of the accident that I can find in this interim report.

OAP

[atakacs]

Happy to see this topic re-opened for posting...

There is indeed a lot of factual findings in that intérim report.

One thing I find interresting is that the engines were all the original 1939 models (I understand upgraded / more powerful engines were later fitted in the JU-52) with all about 1000h since last retrofit. I wonder what kind of actual power they could deliver.

Unless I have missed it no mention of passenger recording. Surprising.

[clearedtocross]

One thing I find interresting is that the engines were all the original 1939 models (I understand upgraded / more powerful engines were later fitted in the JU-52) with all about 1000h since last retrofit. I wonder what kind of actual power they could deliver.
In an earlier interview, the CEO of Ju-Air (before the accident) said that the three engines were rated at 500 hp each, not a lot for a 10.5 t hardware. Looking at the picture of the three cylinders in the interim report, this figure may even be rather optimistic.
Unless I have missed it no mention of passenger recording. Surprising.
The accident investigation (SUST) mentioned that cameras of victims were found, but up to date could not be evaluated due to the damage sustained. So they ask now passengers on earlier similar flights if they would please submit recordings.
There is indeed no statement to the cause of this tragedy. I think they will be very careful to word it even in the final report as it might be fodder for the lawyers. There is strong sympathy for the enthusiasm of the hole outfit (understandbly) and the pilots are mostly of military background who will stick togethter like glue (also understandbly)

[Pali]

Unless I have missed it no mention of passenger recording. Surprising.

It was mentioned at page 15:
An der Unfallstelle konnte eine grössere Anzahl von Mobiltelefonen und einzelne Filmkameras von Passagieren und Besatzungsmitgliedern sichergestellt werden. Diese Aufzeichnungsgeräte wurden beim Unfall teilweise stark beschädigt. Bis zur Veröffentlichung des Zwischenberichts konnten einzelne Datenträger ausgelesen werden. Die Reparatur- und Auslesearbeiten an der Mehrzahl der sichergestellten Geräte dauern aber weiter an und werden noch geraume Zeit in Anspruch nehmen.

Roughly translated: On the accident site a larger number of mobile phones and cameras owned by passengers and crew were secured. Some of recorders were heavily damaged. Until the publishing of interim report it was possible to read data from some devices. Repair and downloading data from the majority of recorders is in progress and will take longer time.

Note: German nor English is not my native language so sorry if is not perfect.

[atakacs]

Thanks. I have missed that part. Surprising that they have managed so little (one device) in 3+ months.

As for the egines I'd be very surprisdd if they could deliver anywhere near their rates output.

[wiedehopf]

Thanks. I have missed that part. Surprising that they have managed so little (one device) in 3+ months.

As for the egines I'd be very surprisdd if they could deliver anywhere near their rates output.
Nowhere does it say one device.
"Bis zur Veröffentlichung des Zwischenberichts konnten einzelne Datenträger ausgelesen werden. "

"Until the date of this report individual devices could be read out.

That would imply several devices could be read out.

[jimjim1]

This document is an interim accident report but,
https://www.sust.admin.ch/inhalte/AV-berichte/HB-HOT_ZB_D.pdf
OAP

I found that a web site[1] that reportedly uses google translate and sorts out large documents for you. I guess it splits the file into suitable bits for google and puts it all back together.

I have not read much of it yet but the first few pages look not bad.

https://drive.google.com/open?id=1MbaxzkChLSJ3BcOYDh4agLS9VQ931JA_

I think that the link should work - I have tested it from a browser than was not logged on to google.

[1] https://www.onlinedoctranslator.com/en/

[jimjim1]

On the basis that I might at least look at the pictures I used google translate against the Figure captions before I found onlinedoctranslator.

These seem in some cases clearer than those in the whole doc translation I linked to above.

Figure 1: Wing section with the 4 bars (Source: Operating Instructions Ju 52 / 3m, supplemented
by the SUST)

Figure 2: Motor mount of the left or right motor (Source: Operating instructions
Ju 52 / 3m)

Figure 3: Maintenance program of the Ju 52
The engines had a maximum allowable according to the maintenance program
Operating time to overhaul (Time Between Overhaul - TBO) of 1500
Hours with a tolerance of 10%. In the operating manual of the aircraft engine
The manufacturer's BMW 132 from 1939 states the following: «One
Overhaul should rarely be required before 200 to 300 hours of operation ».

Figure 4: Accident site southwest of Piz Segnas. A mesh square has one side length
of a kilometer. Source of the base map: Federal Office of Topography.

Figure 5: End position of the wreck

Figure 6: Repair in the area of ​​the wing center box, recognizable by the greenish yellow

Structural parts and the golden connection elements.

Figure 7: Repair of the structure of a motor carrier. The half shells became direct
riveted on the thick paint layer.

Figure 8: Lower spar tube of spar I of the left wing. The arrow points to the zone
with cracks in the spar tube.

Figure 9: Detailed view of the crack zone at the lower spar tube of the left wing.

Figure 10: Detail view of the inner side of the lower side of the left wing.

Figure 11: Detail view of the cabin structure at the rear right. Striking are the rotten ones
Wooden floor (yellow marked zone) and the corrosion damage (red arrows).

Figure 12: Corrosion in the area of ​​the wing connection (red arrows)

Figure 13: Marked aging damage on a hose

Figure 14: Fuel hose with date (November 11, 1988)

Figure 15: Cylinder positions 1, 2 and 3 of the left engine with piston.

Figure 16: Cam of the middle motor. The machining marks are clearly visible
(regular, finely grooved surface) and the eruptions on the upper tread.

Figure 17: Engine components stored in a cabinet and not identifiable.

[atakacs]

Figure 3: Maintenance program of the Ju 52
The engines had a maximum allowable according to the maintenance program
Operating time to overhaul (Time Between Overhaul - TBO) of 1500
Hours with a tolerance of 10%. In the operating manual of the aircraft engine
The manufacturer's BMW 132 from 1939 states the following: «One
Overhaul should rarely be required before 200 to 300 hours of operation ».

I am possibly over obsessing about the engines but

why did they run those very old engines when much better options are available (while keeping with original / vintage JU 52 specs) ? Is there something unique about those ?
they had respectively 946:50 h, 1153:11 h and 457:49 h since TCO - seems a lot (even if formally within tolerance).
This is not looking too good https://i.imgur.com/UiiALFZ.jpg
overall it would seem that these airplanes were not maintained to top standards, so there would be a suspicion that the engines were probably not able to deliver rated power
This might or might not ultimately be related to the accident but I think we can reasonably assume that they did not have a significant performance margin on that day... if at all.

[Onceapilot]

Due to the severe loss of life in this accident, I expect that the final report will be comprehensive. At this stage, with the interim report to guide us, it seems that there might be considerable comment upon the regulation and operation of these aircraft. As for the cause of the accident, I am afraid that it must be pure speculation at this time.
As a point of interest, it should be understood that the internal condition and visual appearance of a high time large capacity piston aero-engine can be disappointing and somewhat dirty. However, the true condition can easily be determined by examination and measurement. Of equal interest to me in this instance, is the precise flying performance of the aircraft and its engines and how it was licensed to operate.
There does not seem to be any guidance on the likely time that the final report will be published, can any member help with an estimate from the Swiss authorities on this please?
OAP

[clearedtocross]

There does not seem to be any guidance on the likely time that the final report will be published, can any member help with an estimate from the Swiss authorities on this please?
OAP
Nope. The accident investigation branch will publish the final report when their findings are watertight, no schedule given. They repeated in the interim report that there was no indication of a mechanical failure or lack of fuel. What else, would George Clooney say, if not an act of a pagan God? Within a few weeks, there were three similar fatal accidents in the Swiss Alps in hot and high conditions. So obviously the tactics and decisions of the pilots will be questionned. Weight and balance will be important (with Pax moving in the cabin). But regarding the operational aspect, there are open questions about the operation, maintenance and oversight by the CAA too. Legally, this was a commercial operation (passengers paying a fee) , and even if the final report is not discussing legal matters, it will have a heavy impact on possible liability claims by surviving dependants. There is no reason to distrust the investigators, but they will have to be very careful in the wording of there findings. And the interim report created already quite an echo in the media and Swiss aviation circles, not only by what it said, but mainly what it did not.

[atakacs]

And the interim report created already quite an echo in the media and Swiss aviation circles, not only by what it said, but mainly what it did not.

Could you expand on that ?

[clearedtocross]

If the investigators know for sure what was not the cause they must have a pretty good idea what the real causes and its contributing factors were. Otherwise they would remain much more fuzzy. And they just reported airwortiness issues, but not how it was possible that they remained uncorrected for quite a while. I refrain from expanding my own conclusions on this.

[EDLB]

It means that the pilots stalled the plane and were unable to recover. Hot, high, changing wind directions on the flight path are most likely contributing factors.