Accident in Namibia, SH Ventus 2cxm

Le mardi 2 février 2016 13:41:43 UTC+1, Dan Daly a écrit*:

You may recall the ETA spin test with one wing full/one empty led to a crash. Both CS-22 AL1 and the ETA test are available by mr. google.

No. The Eta crashed when trying to recover from a spiral dive (dry). The load on the rudder simply snapped the tail boom.

The ASH25 did crash during flight testing when spinning with water in only one wing. The centrifugal force of the water made the wing skin pop, and Martin Heide had to parachute down. He had been suspicious about this outcome beforehand and had tried to talk authorities into dropping this part of the test, but to no avail. So he did the test starting at 10'000 ft.

On Tuesday, February 2, 2016 at 8:48:43 AM UTC-5, Tango Whisky wrote:
Le mardi 2 février 2016 13:41:43 UTC+1, Dan Daly a écrit*:

You may recall the ETA spin test with one wing full/one empty led to a crash. Both CS-22 AL1 and the ETA test are available by mr. google.

No. The Eta crashed when trying to recover from a spiral dive (dry). The load on the rudder simply snapped the tail boom.

The ASH25 did crash during flight testing when spinning with water in only one wing. The centrifugal force of the water made the wing skin pop, and Martin Heide had to parachute down. He had been suspicious about this outcome beforehand and had tried to talk authorities into dropping this part of the test, but to no avail. So he did the test starting at 10'000 ft.

******
According to the Oct 2009 BFU Investigative report 3x221-0/05, the test was a spinning trial with asymmetric fuel (not water as I said - you are correct on that) - page 1 (History of the flight). According to the conclusions, the spin changed to a spiral dive and the use of rudder for recovery broke the tail (page 5). I guess we are both right, and both wrong in some parts! The asymmetric condition was not noted in conclusions, so probably not critical in comparison to the engineering conclusions.

I didn't say anything about ASH25 but it sounds interesting... I did a brief search but couldn't find it online. When did it happen?

Thank you for the correction.

Le mardi 2 février 2016 15:59:41 UTC+1, Dan Daly a écrit*:
On Tuesday, February 2, 2016 at 8:48:43 AM UTC-5, Tango Whisky wrote:
Le mardi 2 février 2016 13:41:43 UTC+1, Dan Daly a écrit*:

You may recall the ETA spin test with one wing full/one empty led to a crash. Both CS-22 AL1 and the ETA test are available by mr. google.

No. The Eta crashed when trying to recover from a spiral dive (dry). The load on the rudder simply snapped the tail boom.

The ASH25 did crash during flight testing when spinning with water in only one wing. The centrifugal force of the water made the wing skin pop, and Martin Heide had to parachute down. He had been suspicious about this outcome beforehand and had tried to talk authorities into dropping this part of the test, but to no avail. So he did the test starting at 10'000 ft.

******
According to the Oct 2009 BFU Investigative report 3x221-0/05, the test was a spinning trial with asymmetric fuel (not water as I said - you are correct on that) - page 1 (History of the flight). According to the conclusions, the spin changed to a spiral dive and the use of rudder for recovery broke the tail (page 5). I guess we are both right, and both wrong in some parts! The asymmetric condition was not noted in conclusions, so probably not critical in comparison to the engineering conclusions.

I didn't say anything about ASH25 but it sounds interesting... I did a brief search but couldn't find it online. When did it happen?

Thank you for the correction.

I think that the ASH25 happened in 1985 or 1986. Martin Heide told me about it a week or two later.

On Tue, 2 Feb 2016 07:12:13 -0800 (PST), Tango Whisky
wrote:

I think that the ASH25 happened in 1985 or 1986. Martin Heide told me about it a week or two later.

.... actually it was the ASW-22 prototype.

On Wednesday, February 3, 2016 at 10:41:22 AM UTC-5, Andreas Maurer wrote:
On Tue, 2 Feb 2016 07:12:13 -0800 (PST), Tango Whisky
wrote:
I think that the ASH25 happened in 1985 or 1986.
Martin Heide told me about it a week or two later.

... actually it was the ASW-22 prototype.

Right, one of two accidents I know of where hydrostatic pressure
blew the wing skins off a -22 (the other a ground-loop).

Led to development of the kludgy isolated tanks, which limit
hydraulic pressure *IFF* there's a bit of air in the tanks.
Don't overfill ;-)

Hope that helps,
Best Regards, Dave

Just going back to the actual topic of this thread, there has been a trace received from the logger of the Ventus in question.
Looks like he exited the thermal at a bit over 4500 meters, and has gently pulled into a turn, stalled, and gone straight down from there. No sign of a recovery.
I will not speculate as to what has happened as he was a friend of mine.