4th Aug 2018 Junkers JU52 crashed in Switzerland
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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.
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.
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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...
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...
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.)
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.)
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...?id=20031217-0
https://aviation-safety.net/database...?id=20031217-0
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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.
Last edited by HarryMann; 7th Aug 2018 at 13:32. Reason: Meaning wrong.. re phrased
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.
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.
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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.
"smoke" looks like grass to me
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"
Last edited by jimjim1; 7th Aug 2018 at 14:13.
Thread Starter
Piz Segnas
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
Cover of the PDF,
Not the first time in this place!
https://www.ju-air.ch/app/download/7...zette-2018.pdf
Not the first time in this place!
https://www.ju-air.ch/app/download/7...zette-2018.pdf
Piz Segnas
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
Thread Starter
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
Thread Starter
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
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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.
You can clearly see the feature that appears to be smoke as a ridgeline.
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Does anyone know if the Martinsloch itself causes any odd wind phenomena? I came across a blog where someone walked/climbed to the Martinsloch and said (translated from German): "A poisonous cold wind blew through the impressive 19 × 17 meter hole. "