Externally, the Antonov An-148 and derivatives are basically a British Aerospace 146 with two engines, but it was actually developed from the An-74. Like its British counterpart, the Antonov has high mounted, swept wings with a significant anhedral. Underwing pylons hold the wide diameter engines with a separate fan exhaust close to the end of the nacelle. The aircraft has two wheel main gears, that retract sideways in the fuselage. The gear doors have a hole that leave the wheel rims exposed when the gear is retracted. The fuselage retains the six cockpit windows of the An-74, and has a rather pointed tail cone. Above is a T-tail with curved dorsal fin.

The different versions of the Antonov An-148 family can be distinguished by looking at

• the shape of the fuselage
• the length of the fuselage
• whether it has the main wheel in tandem or side-by-side
• the way the main gear retracts
• the presence of a cargo door in the rear, sloped up fuselage
• the presence of cabin windows
• the presence of winglets

This is the development aircraft for the eventual An-148. The An-74TK-300 is an An‑74TK with engines under the wings instead of on top of them. That is why it is included here. For the rest it is just an An-74, with a narrower fuselage than the An-148 with a rear fuselage sloping up, a tandem main gear with four separate legs retracting inward in pods and a T-tail with pointed bullet fairing to the front and rear. An-74TK-300D is the designation for the original aircraft converted in VIP configuration.  

The An-74TK-300 is essentially an An-74TK with relatively large engines under the wings instead of on top of them. (photo: Rolf Wallner/WikiMedia)

The An-74TK-300 seems nothing more than a test aircraft for the underwing configu­ration. The An-148 is in many aspects a completely new design with its wide fuse­lage, many small cabin windows, long wing-fuselage fairing, a curved dorsal fin, main wheels on a single axis and legs and large cabin doors at the front and rear. Also, the An-148 has no rear loading ramp and no bullet fairing on top of the T-tail. 

There are several versions of the An-148, of which the 100 and 200 series seem to differ in the rear fuselage section (the 200 having that of the An-158, allowing more pas­sengers), while the suffixes are for variants with different weights and ranges. Outward, they look the same though.

As a minor development from the An-148, the An-158 is about 1.7 metres longer than the original version. That may be visible to the trained eye, but it is easier to look at the wing tips, because the An-158 has winglets. These are small, and up and down, much like on the A310 and A320 family.

With the An-178, Antonov returns a bit back to the original An-72/An-74. The An-178 cargo plane matches the wings including winglets, large wing-fuselage fairing, engines below the wings and tail of the An-158 to a wider fuselage without cabin windows, a rear fuselage sloping up and holding a cargo door, and a tandem main gear like on the An-72. The An-178 has large, single piece main gear doors.