On the fifth day of the Russian invasion of Ukraine, one of many unanswered questions is why Russia has launched a military campaign at huge cost with maximalist objectives, and then declined to use the vast majority of its fixed wing combat aircraft.
The Russian invasion of Ukraine began as expected in the early hours of 24 February: a large salvo of cruise and ballistic missiles destroyed the main ground-based early warning radars throughout Ukraine.
The result was to effectively blind the Ukrainian Air Force (UkrAF), and in some cases also hinder aircraft movements by cratering runways and taxiways at its major airbases.
Strikes also hit several Ukrainian long-range S-300P surface-to-air missile (SAM) batteries, which had limited mobility due to a long-term lack of spares.
These initial stand-off strikes followed the pattern seen in many US-led interventions since the end of the Cold War.
The logical and widely anticipated next step, as seen in almost every military conflict since 1938, would have been for the Russian Aerospace Forces (VKS) to mount large-scale strike operations to destroy the UkrAF.
With its early warning chain blinded and some runways cratered, the UkrAF was left vulnerable to raids by strike aircraft like the Su-34 with guided munitions, or even multirole Su-30 fighters with predominantly unguided munitions.
If present in significant numbers, escorting Su-35 and Su-30 fighters would have overwhelmed the Ukrainian fighters, even if they did manage to take off for sorties conducted at very low altitudes with limited situational awareness. This did not happen.
Instead, the roughly 300 modern combat aircraft which the VKS have positioned within easy range of the main contact zones in northern, eastern and southern Ukraine appear to have largely stayed on the ground throughout the first four days of fighting.
This has allowed the UkrAF to continue flying low-level defensive counter-air (DCA) and ground-attack sorties, and these appear to have had some successes in intercepting Russian attack helicopters.
The fact that Ukrainian troops and civilians have been able to see (and rapidly mythologise) their own pilots continuing to fly sorties above major cities has also been a major morale-boosting factor that has helped solidify the extraordinary spirit of unified resistance shown across the country.
The lack of Russian fixed wing fighter and strike aircraft sorties has also allowed Ukrainian SAM operators and troops with MANPADS such as the US-made Stinger missile to engage Russian helicopter gunships and transports with significantly less risk of immediate retaliation.
This in turn has contributed to the significant lack of success and heavy losses suffered during Russian air assault operations.
Furthermore, the almost total lack of Russian offensive counter-air (OCA) sweeps has been coupled with very poor coordination between Russian ground forces’ movements and their own medium- and short-ranged air defence systems.
Multiple Russian columns have been sent forward beyond the reach of their own air defence cover, and in others cases accompanying SAM batteries have been caught inactive in military traffic jams without making any apparent effort to provide situational awareness and defence against Ukrainian air assets.
This has allowed the surviving Ukrainian Bayraktar TB-2 armed UAVs to operate with considerable effectiveness in some areas, inflicting significant losses on Russian vehicle columns.
The indiscriminate form of air attack that was standard practice for Russian and Syrian Air Force operations over Aleppo and Homs is unfortunately likely to be employed by the VKS over Ukraine in the coming days
There are several factors that may be contributing to the lack of Russian ability to achieve and exploit air superiority, in spite of their huge advantages in aircraft numbers, equipment capability and enablers such as AWACS compared to the UkrAF.
The first is the limited quantities of air-delivered precision-guided munitions (PGMs) available to most VKS fighter units.
During combat operations over Syria, only the Su-34 fleet has regularly made use of PGMs, and even these specialist strike aircraft have regularly resorted to unguided bomb and rocket attacks.
This not only indicates a very limited familiarity with PGMs among most Russian fighter crews, but also reinforces the widely accepted theory that the Russian air-delivered PGM stockpile is very limited.
Years of combat operations in Syria will have further depleted that stockpile, and may mean that the bulk of the 300 VKS fixed wing combat aircraft massed around Ukraine have only unguided bombs and rockets to draw on for ground-attack sorties.
This, combined with the lack of targeting pods to spot and identify battlefield targets from a safe distance, means that the VKS fixed wing pilots’ capacity to provide close air support for their forces is limited.
As a result, the VKS leadership may be reluctant to commit the bulk of their potential striking power against Ukrainian troops before political approval is granted to employ unguided munitions to bombard Ukrainian-held urban areas.
This indiscriminate form of air attack was standard practice for Russian and Syrian Air Force operations over Aleppo and Homs, and unfortunately is likely to be employed by the VKS over Ukraine in the coming days.
Lack of PGMs, however, is not a sufficient explanation for the overall lack of VKS fixed wing activity. The relatively modern avionics on most of their strike platforms mean that even unguided bombs and rockets should still have been sufficient to inflict major damage on Ukrainian aircraft in their airbases.
The VKS also have around 80 modern and capable Su-35S air superiority and 110 multirole Su-30SM(2) fighters, which could conduct OCA and DCA sweeps. The inability to establish air superiority, therefore, cannot be purely explained by a lack of suitable PGMs.
Another potential explanation is that the VKS are not confident in their capacity to safely deconflict large-scale sorties with the activity of Russian ground-based SAMs operated by the Ground Forces.
Friendly-fire incidents by ground-based SAM units have been a problem for Western and Russian air forces alike in multiple conflicts since 1990.
Running joint engagement zones in which combat aircraft and SAM systems can engage enemy forces simultaneously in a complex environment without friendly-fire incidents is hard; it requires close inter-service cooperation, excellent communications and regular training to master.
So far, Russian forces have shown extremely poor coordination across the board, from basic logistics tasks, to coordination of airborne assaults with ground forces activity and arranging air defence cover for columns on the move.
In this context, it might be the case that the decision was made to leave the task of denying the UkrAF the ability to operate to the ground-based SAM systems, with the explicit understanding that this would be instead of large-scale VKS air operations.
However, once again, this is not a sufficient explanation in itself, since given the limited fighter and SAM assets available to Ukrainian forces at this stage, the VKS could still have conducted large-scale sorties against key targets at pre-arranged times, during which Russian SAMs could be instructed to hold their fire.
The VKS leadership may be hesitant to commit to large-scale combat operations which would show up the gap between external perceptions and the reality of their capabilities
A final factor to consider is the relatively low number of flying hours that VKS pilots receive each year relative to most of their Western counterparts.
While accurate numbers across each unit are hard to find, periodic Russian official statements suggest an average of 100–120 hours per year across the VKS as a whole. Fighter unit flying hours are likely to be lower than those for transport or helicopter units, so the real figure is probably a little under 100.
RAF and US Air Force fighter pilots often complain that they struggle to maintain multirole combat readiness with around 180–240 flying hours a year, access to modern high-fidelity simulators for additional training, and better cockpit ergonomics and weapon interfaces than their Russian counterparts.
Therefore, it may be that despite an impressive modernisation programme that has seen the acquisition of around 350 new modern combat aircraft over the past decade, VKS pilots would struggle to effectively employ many of the theoretical capabilities of their aircraft in the complex and contested air environment of Ukraine.
If this is the case, then the VKS leadership may be hesitant to commit to large-scale combat operations which would show up the gap between external perceptions and the reality of their capabilities.
However, it is important to remember that we are only five days into what could easily turn into a protracted campaign.
The fact that there have only been a few confirmed sightings of Russian fixed wing sorties over Ukraine should not obscure the fact that the VKS fighter fleets remain a potentially highly destructive force, and one that could be unleashed against aerial and fixed ground targets at short notice over the coming days.