Russia’s pace of air operations in Syria appears to have dropped off slightly from their peak in recent days. While the Russians had flown as many as eighty-eight sorties per day about two weeks ago, more recently that number has dropped off as many U.S. defense officials had predicted.

“In the course of the last 24 hours, the Russian air group carried out 59 sorties engaging 94 terrorist objects in the Hama, Idlib, Lattakia, Damascus, Aleppo, Deir ez-Zor provinces,” reads an Oct. 26 release from the Russian Ministry of Defense. “In the course of the last three days, the aircraft of the Russian air group have performed 164 combat sorties engaging 285 terrorist objects.”

That means that the Russians have been flying an average of fifty-five sorties per day with their mix of Sukhoi Su-24s, Su-25s, Su-30SM and Su-34s—which is a slower pace than before. But those figures are within the range Pentagon officials had predicted the Russians could fly with the number of jets they have deployed. The Russians are thought to have between thirty-two and thirty-six aircraft at their base in Latakia, which means they could generate with between forty-eight and ninety-six sorties per day with good logistics.

While the Russians initially surprised many with their ability to generate up to eighty-eight sorties per day, most U.S. defense officials predicted those numbers could not be sustained for long. That’s because the Russian don’t have any recent experience deploying aircraft overseas, nor do they have a well-oiled logical train that could sustain the pace for long. Indeed, most Pentagon officials I had talked to expected that logistics would prove to be the Russians’ Achilles’ Heel.

Indeed, USA Today reported earlier today—citing an anonymous Pentagon official—that nearly one-third of Russia’s combat aircraft and fifty percent of its transports in Syria are grounded at any one time. The harsh conditions appear to be taking a toll on the Russian crews and their aircraft.

My own sources said much the same. However, they said that logistics are probably the biggest factor in the drop-off, noting that Russian aircraft usually fare pretty well in harsh conditions because of their rugged construction. Regardless, the result is that the Russians are not quite matching the performance of U.S. Air Force, Navy or Marine Corps expeditionary forces.

However, there is another factor that could be playing a role. The bulk of the Russian aircraft deployed to Syria are either upgraded but elderly airframes or brand new models that have not yet ironed out all of their various teething issues. Elderly aircraft—even refurbished ones—break down and require a lot of maintenance. That’s just a fact of life—and one of the reasons the U.S. Air Force is so eager to replace its oldest fighters (the U.S. Navy’s rebuilt F-14D (R) jets are a good case study).

But the same is true of brand-new aircraft. Until maintenance crews learn a jet’s quirks and which parts need replacing most often, new aircraft that have just entered service have horrible mission-capable rates. It happened with the F-22 when it was first introduced and it’s happening with the F-35 now. And Russia is not immune to the problem. Indeed, Russia’s most capable bomber in-theatre, the Su-34—which has been built in boutique quantities like most of the newest Russian jets—has had severe issues with maintenance in previous years due in part to its slow build rate.

It remains to be seen if Russia will use this as an opportunity to revamp its logistical system. But if it does, it is possible that Russia might be able to ramp up its air operations once its crews learn to deal with the deployed environment and the correct spare start flowing in a timely manner. Only time will tell how the Russians will fare.

Dave Majumdar is the defense editor for The National Interest. You can follow him on Twitter: @davemajumdar.

Image: Flickr/Poter Simon