Dynamics of planar-planar director reorientation under an electrostatic field is studied in nematic cell with the director easy axis gliding. Two cases of the electric field interaction with easy axis at the cell substrate is assumed, linear and quadratic in the electric field. In the case of quadratic interaction the director instability has a threshold. Dependence of the director dynamics on the anchoring energy and the electric field interaction with the easy axis are studied. We calculated the light transmittance of the cell and show that it reflects the director dynamics.