Initial service experience revealed that the ShKAS machine guns had a tendency to jam. This was the result of the guns being installed in the wings upside-down to facilitate the fit. The problem was addressed in later modifications. Evaluations from pilots confirmed the experience with prototypes. Controls were light and very sensitive, abrupt maneuvers resulted in spins, and spin behavior was excellent. An aileron roll could be performed in under 1.5 seconds (roll rate over 240 degrees/second). The machine guns were fired via a cable and the required effort, coupled with sensitive controls, made precision aiming difficult. The rear weight bias made the I-16 easy to handle on unprepared airfields because the aircraft was rather unlikely to flip over the nose even if the front wheels dug in.
The I-16 was a difficult fighter to fly. The pilots had poor visibility, the canopy tended to become fouled with engine oil, and the moving portion was prone to slamming shut during hard maneuvers, which caused many pilots to fix it in the open position. The front section of the fuselage, with the engine, was too close to the centre of gravity, and the pilot's cockpit too far to the rear. The Polikarpov had insufficient longitudinal stability and it was impossible to fly the aircraft "hands off".