View Full Version : Cessna 421B - double fatality - Czech Republic
Heebicka
27th Sep 2017, 09:33
happen yesterday. not much info yet. Just two pilots on board.
The flightradar (https://www.flightradar24.com/data/aircraft/ok-tkf) is ending at around 10.000 AMSL (ground is around 1000 AMSL at that area)
crash site pictures in this article:https://liberec.idnes.cz/ceska-lipa-letadlo-straz-pod-ralskem-pad-cessna-pozar-p0i-/liberec-zpravy.aspx?c=A170926_083704_liberec-zpravy_klu
witness said both engines were out (engine coughing mentioned) and from his description it looks to me he seen that plane in spin.
there is an abandoned military airbase like 5km from crash site with really long and wide paved runway...
rnzoli
27th Sep 2017, 12:26
From the fire, it seems they still had fuel on board. Icing? Contamination?
Oscar Charlie 192
27th Sep 2017, 20:26
FlightRadar24 suggests a Max. altitude of circa 14,000'. Is oxygen, or the lack of, a possibility?
Heebicka
29th Sep 2017, 05:33
Video with last seconds of the flight
yes it was a spin
Pád letadla na ?eskolipsku | Prima PLAY (http://play.iprima.cz/zpravy-ftv-prima/pad-letadla-na-ceskolipsku)
I guess there is not much to say right now and I will update this with authority findings. (6~9 months usually, here)
rnzoli
29th Sep 2017, 08:32
Oh, dear..... terrible to watch. Being helpless. Probably the witness started recording after he recognized that he sees something very abnormal. So the spin may have started much higher up above terrain.
Heebicka
29th Sep 2017, 13:30
Oh, dear..... terrible to watch. Being helpless. Probably the witness started recording after he recognized that he sees something very abnormal. So the spin may have started much higher up above terrain.
Yep. Flat spin. There is another witness statement he hear full throttle for almost half of the fall. This is not exactly a spin recovery procedure
Does anyone have any comment on how easy recovery from a flat spin would or would not be for a Cessna 421 - either with both engines or if asymmetric
Flying Binghi
6th Oct 2017, 20:41
Does anyone have any comment on how easy recovery from a flat spin would or would not be for a Cessna 421 - either with both engines or if asymmetric
With a video to look at showing the hull attitude in the spin i suspect there are some about pprune who could give a fair indication of any possible power influence to the spin.
.
Runaway Gun
7th Oct 2017, 21:23
Ive never spun multi-engine types, however I can say that to get it nice and flat as the video shows, then lots of power and outspin aileron both helps!
I wish all pilots had training in extreme Unusual Attitude recovery, and spins.
Pilot DAR
7th Oct 2017, 23:37
There is no certification requirement that multi engine aircraft demonstrate spin recovery - maybe they do... maybe they don't, it's an unknown. Depending upon c of G position, and the amount of fuel in the tip tanks, the possibilities of spin recovery at all could be greatly affected.
Does anyone have any comment on how easy recovery from a flat spin would or would not be for a Cessna 421No body knows, that's why aircraft meant to be spinnable are put through flight test, with due precaution such as a spin chute to aid recovery should problems arise, and pilot with a parachute should that fail. And it does, test pilot of the Australian GA8 had to bail out when it failed to recover. On exit he fell through the prop arc, fortunately the prop had stopped, and the angels smiled.
The CAC Winjeel had spin recovery issues and the fin had to be moved forward to alieviate. Compare photos of prototype and production.
http://www.adf-gallery.com.au/gallery/albums/Winjeel-A85-364/Winjeel_A85_364.jpg
http://www.adf-gallery.com.au/gallery/albums/Winjeel-A85-364/BK_2A85_364.jpg
Some of what may be involved in spin testing.
3cJkjk0hOU8
Pilot DAR
8th Oct 2017, 15:39
For review, spin recovery will become more difficult/impossible if the rotation cannot be stopped, and the nose not substantially lowered as recovery is initiated.
Rotation stopping may be degraded because the rudder is ineffective (perhaps blanked), or inertial forces of rotation too great for the rudder to overcome (engines, fuel in tip tanks).
Lowering the nose will be affected by elevator effectiveness (blanked or disturbed air off wing, fuselage or fin/rudder), or aft C of G elevator cannot overcome.
During spin testing I flew in a modified Cessna Grand Caravan, the aft limit configuration showed and aircraft which was not eager to recover. It did, but it made you sweat, as the nose could not be forced much below the horizon. Watching the video of the doomed 421 reminded me of having difficulty getting the nose down to initiate recovery. When I was doing it, I had many more thousand feet under me....
horizon flyer
8th Oct 2017, 19:21
I studied the clip, is it just me but I think it looks like an inverted spin?
What does anybody else think?
Inverted? No, it is erect, and you can see that from the close up photos of the wreckage.
In response to a number of flat spin accidents in the Beech Baron, the US Army spin tested the airplane in 1974. One of the most noteworthy published findings was that it took less than one second for the airplane to spin following a single-engine stall. Immediate recovery action was needed to avoid spinning. In 1998 and 2002 the Raytheon Aircraft Company published safety communiqués reporting the results of 229 spins in Baron Models 58 and 58P. With the windmilling left engine idle with max continuous power on the right engine throughout the stall, entry to beyond 270 degrees of rotation, the spin was unrecoverable requiring the deployment of the spin chute. Part of Raytheon’s published recommendations was:
“During single-engine operation (actual or simulated), at the first indication of approach to stall (the stall warning horn, buffeting, or both) stall recovery must be initiated immediately … if this instruction is not followed, a stall will occur and a dangerous spin is likely to occur”.
Just my observation, the 421 having the swept back fin, the same as the Baron, the rudder would be blanked from the airflow by the tailplane and rendered useless ie irrecoverable spin, unless caught during the first turn, as in the Baron case. Just guessing, DAR would be able to give insight.
http://www.faa.gov/news/safety_briefing/2012/media/sepoct2012.pdf (https://www.ntsb.gov/safety/safety-recs/recletters/A81_49_53.pdf)