Sukhoi Su-27 variant
Sukhoi Su-27 Su-27UB1M
The Su-27UB1M is the Ukrainian Air Force's two-seat Su-27UB combat trainer modernised under the Su-27-1M programme at the Zaporizhzhia aircraft repair plant (ZARZ "MiGremont"). Together with the Su-27P1M, it is the subvariant sources place at the start of the programme, in the early 2010s. It keeps the tandem two-seat layout and the dual role of the baseline version: training crews and fighting. The installed package is the family's — an N001 radar station with new receiver blocks, an SN-3307-02 satellite navigation receiver, ICAO-compliant Kurs-93M-V equipment and an A-511 transponder, and a solid-state SAVR-27U recorder — and its stated purpose expressly includes the flying and tactical training of pilots in operational units. It was formally adopted into the Ukrainian Air Force on 5 August 2014, by order No. 499 of defence minister Valeriy Heletey, alongside the Su-27S1M, Su-27P1M and Su-27UP1M. Deliveries of individual aircraft have come in a trickle: a first modernised two-seater was handed to an operational unit on 31 January 2020 and another on 6 December 2021. The pace reflects both budget limits and the plant's real capacity.
History
The two-seater within the programme
Ukraine took on the modernisation of its Flanker fleet in the early 2010s at the Zaporizhzhia plant. Sources indicate the first standards applied were the Su-27P1M and the Su-27UB1M — an air-defence single-seater and the combat trainer.
Content of the upgrade
The additional equipment kit is common to all four subvariants: an upgraded N001 radar sighting station with new receiver blocks, an SN-3307-02 satellite navigation receiver, ICAO-compliant radio navigation and communications through the Kurs-93M-V suite and the A-511 transponder, and a solid-state SAVR-27U audio-video recording system. Neither airframe nor engines are replaced.
Adoption and deliveries
Ministerial order No. 499 of 5 August 2014 adopted the Su-27UB1M as a combat trainer of the Ukrainian Air Force. Documented deliveries of modernised aircraft to operational units include one on 31 January 2020 and another on 6 December 2021.
Distinction from the Su-27UP1M
The same order adopted the Su-27UP1M, the upgrade of the Su-27UP, the air-defence patrol and training two-seater. Both are two-seaters and share the package; they differ in baseline aircraft and assigned role. Public documentation on the UP1M is markedly thinner.