Some Mechanical and Structural Aspects of the Smolensk Crash
By Dr. Gregory Szuladzinski, Ph.D., MSME
SCND2014GS

2. Anticipated and Real Structural Damage, Comparison

In the vicinity of point K a sudden event took place causing a change in course. (TAWS, Figure 2). The altitude was greater than 30 m and horizontal speed - about 270 km/h. Trees and forest undergrowth at the emergency landing area, had a tendency to reduce the horizontal velocity. ("Emergency landing" is used here as a loose term, meaning contact with the ground, no matter how undesirable the circumstances.) Elastic properties of the soil should act somewhat like a shock absorber, reducing the peak vertical acceleration of the fall. There were no obstacles in addition to trees, which could have significantly slowed down the machine. The effect should not be much larger, then then driving a car into the shrubbery of a grove at a speed of 150-250 km/h, which is the estimated speed at the time of impact. (At such a supposed grove, thin trees would need to be quite thin, as we compare the plane of a length of about 50 m to a car, less than 5 m).

What should be expected in such a case? As for the plane, the skin would be broken at places and much crumpled sheet metal would result. The wings could be badly broken, but the fuselage should have only a limited breaks and locally damaged areas. Actual photos of the wreckage of the plane shown in Figure 3 and Figure 4 do not agree with such expectations.

Above: Fig. 3a. A reassembled plane wreckage on the tarmac as seen from behind. The left wing is on the left.

Above: Fig. 3b. It is an enlarged part of Figure 3a, showing the left edge of the torn fuselage, torn under passenger windows.	Above: Fig. 4. The wreckage on the tarmac as seen from the front. On the right one can see remnants of the left wing. It seems there is no clear connection with the rest of the center wing.

Not only are the wings broken, but the hull is in pieces. The front part of the fuselage, in front of the wings, fell into normal position, while the rest of the hull fell "on the back". In other words, the rear part of the plane rotated in flight
Figure 4 also suggests that the front ceiling of the fuselage has not been found or has been fragmented into pieces too small to combine them in the "outline".

Figures 5 - 9 [below] show the remains as they fell, shortly after their discovery.

The devastation is much more thorough than an emergency landing would warrant, both in space and in the nature of the damage. There are tens of hundreds of large and small pieces. Mechanical impact to the ground, after a partial slowdown through the trees, does not justify such a fragmentation of structure. ("Emergency landing" is used here as a loose term, meaning the plane's contact with the ground, no matter how undesirable the way).

Above: Fig. 5. The remains of passenger cabin (parlor/lounge) in the correct position on the ground. Also, remnants of the chassis front, separated from base.

Above: Fig. 6. Part of cockpit and front of main cabin in correct position on the ground

Above: Figure 7. Main, passenger part of the hull, torn and upside down. The left and right side of the blown passenger cabin can be seen open to outside. A part of the plane's ceiling on the right.

Above: Fig. 8. Part of the rear segment of the fuselage, upside down.	Above: Fig. 9. Rear part of the fuselage and wing, which landed up-side-down.

Above: Figure 10. The upper skin (No. 16) and lower (No. 2 according to Figure 11) removed from the left wing, on the tarmac. The lack of the wing's supporting structure (longerons) between skins, which must have been blown-out, is striking. In the crash scene both skin elements are spaced apart by more than 40 meters. The destruction shown in Figure 10 does not determine whether the break-out began in the interior of the wing, or from outside of the leading edge. It only shows the effects of a strong shock wave penetrating into the wing.

Above: Figure 11. View of the left wing, as seen from the bottom. List of found parts.

1. Left center wing
2. Removable part of the left wing (bottom skin with Polish emblem - white/red chessboard)
3. End part of the wing
4. Deflector (end part)
5. Fragment
6. Fragment
7. Reducer
8. Fragment
9. Center slot, Section 2 (left fragment)
10. Center slot, Section 2 (middle fragment)
11. Center slot, Section 2 (right fragment)
12. Center slot, Section 2, (left fragment)
13. Interior slot
14. Broken away Longeron 1 of center wing with skin fragment
15. Broken away Air Conditioning block with skin fragment
16. Removable part of the left wing (upper skin over Polish emblem)