An-2 TBC-2MC (Honeywell remotorized) crashed in Naryan-Mar
 

At takeoff



11 on board, 2 reported dead (woman and child)

IAC: http://mak-iac.org/en/rassledovaniya...60-19-12-2017/

Plane: https://russianplanes.net/reginfo/111965

UPD: 2 dead on site, 2 in hospital which brings death count to 4 now

UPD2: Preliminary cause according to MAC (IAC) is engine failure.

Control Problems?
 

Looks like a control problem-not hot dogging. Something like a control lock or aft c.g, or control system FOD.
Once the crew recognized the uncontrollable pitch up, seems like they did a pretty good job by rolling to the nearest horizon and letting the nose fall, but they were not quite able to roll back to wings level before intersecting the ground. Their sink rate was nearly stopped, and that must account for the relatively low fatality count.
I was not able to get the Russian link to open, so I do not have the local comment that probably is more specific as to cause.
The two fatalities are a sad reminder of the inherent dangers in aviation. R.I.P.

It could as likely be a turn back to the runway in use following, say, an engine problem.

Looks more like a control lock problem. A controllable AN2 you get about anywhere on the ground so no need to turn back to the runway. They where obvious too slow. Even if the pilot had the idea to turn back he would have traded that little altitude for speed.

I guess the footage could be interpreted in different ways. Looks to me like a stall with the right wing dropping, picking up a bit and then turning into the beginnings of a spin. We'll have to wait for the report to know for sure of course.

Not a recommended option at low level I thought.

An engine failure should not have this consequences, particularly on the AN2. Looks like loss of control, question is why. Turn back to the field could be one reason but again, why you can land the AN2 almost eveywhere.

Accelerating towards the ground seems to indicate a stall.

The AN2 cannot stall, the worst it can do is mush into the ground at parachute descent speed. SOP for engine failure in IMC is stick hard back, slats open automagically and it mushes harmlessly into whatever terrain is around.The only logical reason for this one as filmed is an elevator jam hard upwards.
They did well to manage to hit the ground in a level attitude.

Looks like an aft C.G. or elevator locked.

Local people confirmed power loss on TO, attempt to turn back because of fence and forest on the course.

Must be a rare thing to have some turboprop fail this way. Hope they used the right fuel.

Lokking at the foreground, my first thought was ice!

The AN2 certainly can stall. It won't stall decelerating in level flight because as you state it ends up just mushing into the ground at high AOA. Pitch the nose up 20 or 30 degrees however and it will decelerate rapidly and stall like any other aircraft.

Thats one thing I was never daft enough to try. Not sure if it is even possible with the original piston engine.
Lots of fun tricks like landing with zero ground speed or even backwards in a headwind but aerobatics was never on my list.

It's not certified for aerobatics.

I watched an An2 get airborne at the piano keys at Holguin, Cuba. He was airborne at probably over 100' by the time he had passed the far end of the keys. He took off with most of the runway behind him and about 200' beyond the keys in front. With a slight tailwind.

Standard ICAO threshold markings are 30 m long, which is close enough to 100 ft, so if he was airborne at the markings, and 100 ft in the air at the far end of the markings, that would mean that he climbed 100 fr in 100 ft, or a climb angle of 45 degrees ... with a tailwind.


That seems a bit ... improbable.

A slight tailwind and improbable as it seems it was remarkable. He had just dropped pax at the military terminal and had a very short taxi to the threshold.

Sailvi767 :
I did my An2 type rating in Poland some 25 years ago but sadly never flown it afterwards, but I remember quite well that it indeed does not physically "stall" in the known sense . There is also no "stalling speed " on the airspeed indicator or in the Flight manual.
If my meorys erves me well what happens if you pitch up 20 or 30 degrees as you say and cut the throttle, is that at around 60 km/h the slats will automatically come out aerodynamically and you will start descending gently , you can keep control until about 40 K/h . If you try pitching up more up, below 40Km/h , you will loose control (not enough air flowing over the control surfaces) and the nose will come down automatically, putting you back above 40 Km/h . Quite an interesting aircraft.

What we see in that video is not a stall but something more dramatic as suggested here.

Page 144 of this PDF of the Fight Manual for a standard engine AN2 describes AN2 stalls (if that's what you call it).


https://www.dropbox.com/s/l8el56skt5...FCOM1.pdf?dl=0


Is it possible the ground witnesses just heard power being removed, and not an engine failure?

Any news on the survivors that may also include the pilot?

Thanks Bend a lot for this wonderfully translated flight manual. Helps get my memory back.. and more or less confirms what I described. It was long time ago.

Looking at the photo of the aircraft ( second link on original post ) I can see that this (quite ugly) engine modification probably changes a lot the flying characteristics of the airplane , would it be only its CG .
We're not talking about a standard fool-proof plain vanilla AN2 there...:hmm:

One would think any engine mod would keep the same C of G and just give power improvements??

I do have all Maintenance and Delivery manuals for the AN2 in English for any that wish them free of charge (they cost me a lot).

This mod definitely changed a/c a lot. First, it's now tail balanced (and need additional 60kg or two additional acc at front for neutral balance). Second, this engine has much more power than vanilla An-2 also 5-blade propeller is more efficient. Rumors are, there was an usual way of Naryan-Mar pilots to "demonstrate" it by steep climb at TO.

certificate of airworthiness
p.14

From my Experience the AN2 will stall in one single Configuration, with a sharp break: Power ON and Flaps 30 or more. I flew the An2 for 10 yrs in my Sparetime, under AOC in Germany. Later i trained the new Pilots for the Company and had one nasty Experience. With a Pilot i knew very well we did the Power on stall, and the ( Aerobatic Qualified) Pilot got a bit slow with his feet, when the wing dropped. This ended with a 3/4 Incipiend spin and Recovery. You Need 4 Hands in this Situation, because in no time you are above Vfe (150kmh) - Power off - Opposite Rudder and Push, everything at the same time.... With a load of 11 Pax this would Situation would even develop a lot more Aggresive.
This Accident Looks a lot like a Flaps T/O Stall under Power, with the Exception that the Orginal AN would Spin to the Left.