Much damage was done at Grozny, but the remaining oilfields were beyond the logistical reach of the German Army as well as of the fighter aircraft of the Luftwaffe. Grozny was within range of German bombers from 4th Air Corps, based near the Terek River. But Grozny and the captured oilfields at Maykop produced only ten per cent of Soviet oil. The main fields at Baku were out of German fighter range. German bombers could have reached them, but it meant flying the most direct, thus most predictable route without protection. In August it may have been possible to carry out these operations owing to the weakness of Soviet air power in the region, but by October it had been considerably strengthened.