The Brazilian TURBO PROP aircraft which fell out of the sky the other day.
Remember, it made a sound like a helicopter blade.
After a little research, I'm debunking the icing anon, who the other day
was really quick to put forward that theory. What followed was media calling icing.
Either icing anon was shilling a false reason for the flight to crash or was mistaken.
If we think about it logically, the TUTRBO PROP aircraft is so named, as it has the ability to change the propellor blade angle.
It can rotate blades to gain different pitch angles, giving it the ability
to reverse thrust for use in braking after landing and reversing from a parked location.
The wing blades have inflatable edges, giving it the ability to crack ice formed on leading edge.
The helicopter sound matches to the propellor blade pitch being changed,
meaning forward thrust is reduced. That matches the observation
of the planes engines roaring at full thrust trying to gain airspeed.
To maintain propeller efficiency across a wide range of airspeeds, turboprops use constant-speed (variable-pitch) propellers. The blades of a constant-speed propeller increase their pitch as aircraft speed increases.
https://en.wikipedia.org/wiki/Turboprop
The propeller itself is normally a constant-speed (variable pitch) propeller type similar to that used with larger aircraft reciprocating engines, except that the propeller-control requirements are very different.[13] Due to the turbine engine's slow response to power inputs, particularly at low speeds, the propeller has a greater range of selected travel in order to make rapid thrust changes, notably for taxi, reverse, and other ground operations.[14] The propeller has 2 modes, Alpha and Beta. Alpha is the mode for all flight operations including takeoff. Beta, a mode typically consisting of zero to negative thrust, is used for all ground operations aside from takeoff.[14] The Beta mode is further broken down into 2 additional modes, Beta for taxi and Beta plus power. Beta for taxi as the name implies is used for taxi operations and consists of all pitch ranges from the lowest alpha range pitch, all the way down to zero pitch, producing very little to zero-thrust and is typically accessed by moving the power lever to a beta for taxi range. Beta plus power is a reverse range and produces negative thrust, often used for landing on short runways where the aircraft would need to rapidly slow down, as well as backing operations and is accessed by moving the power lever below the beta for taxi range.[14] Due to the pilot not being able to see out of the rear of the aircraft for backing and the amount of debris reverse stirs up, manufacturers will often limit the speeds beta plus power may be used and restrict its use on unimproved runways.[14] Feathering of these propellers is performed by the propeller control lever.[14]
Anon is therefore surmising the propellor pitch was remotely controlled in order to stall the plane, which is exactly what we observed in flight on video's.
Very similar set up to the Bombardier Q400 in Air Berlin livery. And we saw the capabilities of the Q400 as flown by stolen plane guy.