Malibuflyer wrote:
Hasn’t there been another accident report recently where a pilot who also had high hours with most of them in jets crashed while trying to pass a ridge but it turned out that the climb performance of his SEP was just few 100 feet short of the ridge? Same pattern: Experience in Jets sometimes is in the way of good decision making in piston aircraft…
That accident happened the very same day and involved a hugely experienced test pilot for a major Swiss airplane manufacturer and his family.
Final Report here:
https://www.sust.admin.ch/inhalte/AV-berichte/2366_D.pdf
Gist:
The pilot had very few experience on the airplane in question, he had actually not flown it for over two years before the accident flight.
The aircraft was close to MTOM.
The internal procedure of the flying club used a take off and climb power using 2500 RPM instead of Maximum Take Off Power. Consequently the airplane only climbed with roughly 400 fpm.
The view over the front of the airplane with this plane is very restricted.
The airplane took off from Kägiswil and flew pretty much straight to the accident site. With the normal power, it should have overflown the ridge by a good margin, with the reduced power he hit it.
Major difference to the JU Air crash is that in this case, the pilot was quite experienced in total, but had only very few experience on SEP’s and NONE in the last two years with the airplane in question. Also it is pretty clear that he never realized he was in a hazardous situation as there was no attempt whatsoever to correct the flight path or to do anything at all before the collision. It looks as if he was totally surprised by the collision, after which they had no chance at all. There is no indication whatsoever of recklessness or intentional busting of limits e.t.c.
The Ju Air Pilots were as experienced as it gets on their airplane and intentionally flew it the way they did.
T28 wrote:
It works in a glider with low inertia along a ridge where you can turn away from the rock.In a larger plane caught in a downdraft in a bowl valley with no guarantee of a subsequent updraft it’s not a winning strategy.
Agree, it’s not guarateed to work with lot of inertia: one has less clue what is going on with all lags and going faster means wide valleys
Engine or not, if you hit a sharp -/+2000fpm, it can’t hold level at 100kts as it will get +/-12deg AoA right away before aircraft or pilot notices on ASI/VSI
It will be impossible to keep AoA between -4deg/+14deg playing in tight corners
Gliders give instant feedback and stay controllable at high AoA but it’s very limited by pilot teeth on the high speed range 
Snoopy wrote:
Wasn’t this the problem? That they were pitch up/high AoA in the ensuing updraft?
They were pitching up already to climb (already at a high AoA), then when they subsequently encountered the updraft they were already pitched up and at a high AoA, which meant they exceeded the critical angle of attack.
Yes but there is some “history or path dependecy” before
The quickest way to maximize energy (speed & altitude) is to accelerate in sink THEN slow down in updraft
If sink = updraft, after speed reverts to it’s value more height will be gained: more time spent in updraft and less time spent in sink
The fastest way to lose energy (speed & altitude) is to slowdown in sink THEN slow down even more in updraft
If sink = updraft, both speed & height are lost and energy burns even quicker if you add parasite drag near stall
If they pitched down in the sink they would have end up with more height (or less loss ) and more speed stall protection
Takes lot of guts to point the nose down to the ridge if you are caught in rotor but beleive me it works
Ibra wrote:
You pitch down in downdraft andyou pitch up in updraft,
so that the AoA stays on same safe and efficient low drag value while losing minimal height as you spend less time in sink and more time in lift (soaring101)
Wasn’t this the problem? That they were pitch up/high AoA in the ensuing updraft?
I agree, very well written indeed.
The implications of the whole accident and the way Ju Air was operated onto the warbird/historic scene unfortunately will be severe. Which is quite unfair to those who kept the rules and did their darn best in other outfits. But when confidence is shaken in such a brutal way, it is clear that regulators have to re-think what they can do and what not.
All in all a great pity. I´ve flown on the JU twice and on the DC3 ops (Classic Air and the short lived Swissair revival) several times, they were unforgettable flights. Without any doubt, the Ju Air flights would have been attractive even without employing dangerous tactics in Alpine environment.
Here is a link to the last flight I ever did on board the JU, HB-HOP, which likely will be the survivor now being restored for display flights. It was in 2010 and the way I experienced it, none of the rulebreaking which developed later was evident. It was a great memory, regardless of what happened later. Yet, the let down by what happened is so much the more frustrating.
That’s very well written. Wonder why both originally rostered pilots bailed just a few days before the flight.
There’s a write up here (written for general audiences, but with lots of interesting info): https://admiralcloudberg.medium.com/last-of-the-warbirds-the-2018-ju-air-junkers-ju-52-crash-82d41c659dfb
Antonio wrote:
For SUST, it all started with Überlingen.I am afraid Switzerland , together with France (although for different reasons), is nowadays the advanced-world leader in this flight-safety-destroying practice.
I agree. Fully.
T28 wrote:
Having said that, that valley is an U-shape about 1’000m ridge – to – ridge; I don’t know what the turn radius of a Junkers at cruise speed is but I certainly wouldn’t want to have to try an U-turn in there (in that size aeroplane).
Minimum turn radius in level flight for “low-performance” aircraft is not a function of airplane size but rather of stall speed in true terms KTAS (plus half the wingspan, but 5 metres up or down will not make a difference to this effect). I believe the stall speed of a heavy ju52 at around 65KIAS is on par with a lot of light aircraft.
In any case, a turn at 30deg bank and 100KTAS, with reasonable margin to stall, will result in 470m radius, so a 1000m diam level u turn is not a place you want to be in with any aircraft in such situation. As discussed better position yourself for a 90 deg turn away from the pass , preferably from the upwind side with no obstacles in sight for the downwind and downhill turn.
