[2] While the type did enter use on the Berlin-Prague-Vienna route, but the Avia 51 was found to be uneconomical due to its small passenger capacity.

Specifically, duralumin and high-tensile steel were the primary metals used; various protective measures to prevent or minimise corrosion were used, including cadmium plating, painting, and lacquering.

[4] These spars, which were composed of duralumin, worked in combination with a series of booms and ties to form an N-shaped girder.

[4] The rounded side of the booms faced inwards rather than outwards, despite this arrangement placing the rivets closer to the area subjected to the maximum amount of stress, but made the attachment of the ties potentially easier.

The support areas were relatively small, comprising six primary longerons with intermediate stringers, while closely spaced double-walled bulkheads were present with lighter formers positioned between them.

The exterior covering was composed of sheet duralumin, which was riveted to the longerons, stringers and double-walled bulkheads, but not to the intermediate formers.

These elongated legs gave the aircraft that a favourable ground angle while also permitting a lengthy range of travel for the wheels.

[4] Fuel was carried in two tanks, each accommodating up to 16.5 gallons, that were constructed of soldered brass and located within the wing between the spars.

[3] The Avia 51 entered service on the Berlin-Prague-Vienna route, but the type quickly proved to be uneconomical to operate as a consequence of its relatively small passenger capacity.

It was further alleged that the other two aircraft had also been intended for Spanish service, but had been lost at sea as a result of the freighter carrying them to Bilbao being sunk.

[1] Data from The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985),[1] The Avia 51 - The Czech high-performance passenger plane[2]General characteristics Performance