There is no special preference for twin engine - there was actually a preference for single engine 4.5 gens (what SEF was about) because you need large numbers of 4.5G SEFs in order to keep up sortie rates & availability in peacetime & early on in the war while still maintaining combat edge i.e. true replacement for MiG-21s.
There is a need for both, but the TE preference is real.
Raha:
spsmai.com
He stated his personal preference for twin engine to cover the varied geographies of our county.
Dhanoa:
"The RFI for the single engine fighter is likely to be issued very soon," Dhanoa said addressing a press conference.
economictimes.indiatimes.com
The IAF chief, however, said the force has requirement of twin engine jets as well.
Basically, if it's not Rafale, it has to be something else, whatever comes out of MRFA. And if the IAF is to prevent adding more animals to the zoo, this tender can only serve to buy time for AMCA. ORCA's a pie in the sky.
What's needed from the current tender is a 4.5G jet that can lift a considerably higher payload than Tejas Mk-1, and has AESA + IRST. Which is why F-21 and Gripen E are still competing.
Actually, if you've read the second article I posted, they responded to the initial single engine tender. It's only after GoI interference that the tender switched back to twin engine again, they didn't want a single vendor situation with only 2 competitors. And as was the case with MMRCA, it would be rude to kick the two jets out in the new tender. Currently, both F-21 and Gripen E are pointless existences to the IAF. This requirement has already been replaced by the LCA Mk2.
Whatever requirement for twin-engine 4.5G jets still remains unfulfilled (for DPSAs) can be met by 36-57 more Rafales.
The TE requirement is 200-250. And one of the core criterias within requirements is geography. The only real option is to replace the MRFA with something else that has two engines. We need 36-57 in each sector, and we have 3 such sectors, N, SW and NE. Hence the need for 6 squadrons at the minimum or up to 9 optimum. You can bet that this new tender will come at least with 2 bases.
You can picture it in your mind too. Say, 2 squadrons in the N, 2 in the NE and 2 somewhere in the center or the SW. One base is almost always away from where the fighting is happening. So the IAF is at least preparing for 7-8 squadrons in total. The remaining requirement can be fulfilled by AMCA as and when it becomes available. You can even buy 50 squadrons of LCA, but you still need these 2-3 squadrons of TE jets in every sector.
Not to mention the hard fact that a fleet of 126-189 foreign IP twin-engine 4.5G jets of Western standards are simply beyond our financial means even for an off-the-shelf buy, let alone local production which is even more expensive. They always were beyond means - which is why the original tender only resulted in a buy of 36 jets, and why the new one got slashed to 57 (and might yet end up being a buy of only 36 again).
The old tender died due to a multitude of reasons, it was set up for a country managing 8-9% growth in GDP. But the new tender has less to do with affordability and more to do with bean counting. The govt has simply decided it doesn't want to spend so much money all at once. 114 jets will lock up capex funds, but splitting the numbers into two different deals would mean the other half can be spent today, while the first 57 deliver. The IAF is bound to get all 6 squadrons this way. And if this happens, it's an overall superior deal compared to buying all at once. We get to save half our money at first and we also get to bring in new versions later on.
You also have to remember that the IAF will not have any other option until AMCA Mk2 is ready, that's easily around 2037 or beyond, which is a very sketchy schedule at best, but still a 15-year hole to plug at the minimum. 20 if we actually consider the delivery of the first 5 AMCA squadrons too.