Built in 1978, delivered to Aeroflot's Kazakh division and modified as a laboratory aircraft by 1990 with ASLK-75 equipment for navaids testing (ASLK = Avtomatizirovannaya Sistema Lyotnogo Kontrolya). By time of this photo, in these red and blue colours with Spetsavia titles (new name for Bykovo flight check unit). Registration changed to RA-26507 by 1996 and transferred to KAPO im. Gorbunova in July 2012 and Sev-Avia in September 2015, still as a lab aircraft

Navaid check aircraft, by this time in Spetsavia markings. Details with my 1999 photo at Bykovo. Last noted at Nizhny Novgorod in August 2024

Built for Aeroflot as an AN-24LR ice-reconnaissance aircraft with a "Toros" (ice hummock) SLAR and the wing, engines, APU and fuel system of an An-26 in 1970 and registered as CCCP-46395. Converted to an AN-24B experimental navaids aircraft and reregistered as RA-46395 in 1993. To Bykovo Avia in 1994 but remained in Aeroflot colours, Spetsavia in 2002 and Lyotnyye proverki i sistemy by 2007.