  We present an analysis of the optical observations of Herbig AeBe star V1686
Cyg, which is associated with a small isolated star-forming region around HAeBe
star BD+40$^{\circ}$4124. We observed this star as a part of our project of
young eruptive stars investigation. Observations were held on 2.6m telescope of
Byurakan Observatory from 2015 to 2017. For this period we obtained V1686 Cyg
direct images and 14 medium- and low-resolution spectra. In the course of
observations we noticed that this star underwent a not-typical brightness
outburst. After data reduction we found that the full rise and decline of V1686
Cyg brightness had almost 3 magnitudes amplitude and lasted about 3 months. We
were also able to trace the changes of the stellar spectrum during the
outburst, which are correlated with the photometric variations.
