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At what altitude did the weather-research An-4 biplane fly?

Short answer

Up to 10,000 m: the An-4 — the design-bureau designation for the meteorological An-2ZA, intended for high-altitude weather research — could maintain power up to that height with an ASh-62IR engine fitted with a TK turbosupercharger on the right side of the cowling. It included a glazed station for an observer.

Published: November 1, 2026 · Updated: November 1, 2026 · Edited by Above Ten Thousand · Editorial policy

At what altitude did the weather-research An-4 biplane fly? — Antonov An-2 Colt, Lufthansa livery, Sanicole Airshow 2007

The An-2ZA, An-4 at the bureau

The An-2ZA variant of the An-2, whose design-bureau designation was An-4, was specifically intended for high-altitude meteorological research. The ZA suffix comes from Zondirovanie Atmosfery, which can be translated as "atmosphere sampling." For onboard work, a glazed station was fitted immediately ahead of the fin, intended for an observer.

Power up to 10,000 metres

The An-4 was able to maintain power up to 10,000 m: its ASh-62IR engine carried a TK turbosupercharger mounted on the starboard side of the cowling. Compared with the standard An-2, the propeller spinner was removed to improve engine cooling, and the original ailerons were replaced with slotless ones.

The turboprop derivative of the An-2

The An-2 also gave rise to the An-3, a turboprop development intended to modernize or replace it. The update consisted of replacing the piston engine with a 1,025 kW (1,375 shp) TVD-20. The first example flew on 13 May 1980.