The two major problems that the Soviet ekranoplans faced were poor longitudinal stability and a need for reliable navigation.

To correct the poor stability, project engineers decided to increase the flap/speed brake trailing edge thickness.

Crystals that are water-soluble, volatile or organic tend to give poor stability.

The traditional chemical UV protection approach suffers from its poor long-term stability.

The results were unfavorable, indicating poor longitudinal stability at high angles-of attack.

The absence of a keel is a problem, as is poor stability.

The most serious problems were their slow diving time and poor stability during diving.

It proved to have poor longitudinal stability and the powerplant itself still had a number of problems.

Moreover, they have poor stability, becoming brittle or discoloured with age.

It proved to have poor stability and water handling, while the engine installtion overheated.