Aircraft leasing companies gazing at a looming sanctions deadline to take back more than 400 jets worth almost $10 billion from Russian airline operators.

As part of the sanctions on Russia's invasion of Ukraine, Western states ordered aircraft lessors to repossess their leased aircraft to Russian operators until March 28. Western leasing companies are now terminating their contracts with Russian airlines and asking their ex-customers to return the planes. But that is not happening. Russian authorities are reluctant to cooperate with their western counterparts.

"There is nothing official, but Russian airlines are not giving aircraft back. The only ones are a handful that was already outside Russia and could be repossessed," said independent aviation adviser Bertrand Grabowski.

Russian carriers have around 515 jets in their fleets leased from global commercial aircraft lessors. Experts warn that leasing companies may face mass bankrupts if Russian carriers do not return those planes.

In general, it is a very bleak picture. This will end up in the courts forever. Between the airlines, lessors, and insurers, you are most probably looking at a decade of lawsuits, same sources said.

Insurance companies are also at risk since lessors are banking on a record payout under war-risk insurance. A war declaration is not necessarily required to claim under a war-risk policy, insurers say. Nationalization, seizure, and constraint under government orders are also covered.

The current situation also jeopardizes the liability of the Cape Town Convention, an industry circuit-breaker established to make contracts more enforceable in every part of the world.

Western leasing companies are looking for ways to transfer their portfolios with Russian carriers to Chinese lessors since China is one of the few countries continuing to keep its relations with Russia at the pre-war level. An expert working for a Chinese lessor said transferring the leasing agreements to a different entity would require dealing with tons of paper and legal work that have very little chance of success.

Even if the war ends, Russia's extended isolation may forever damage valuations of unpossessed airplanes by interrupting the continuity of maintenance records. Lack of spare parts may encourage Russian airlines to swap parts locally without any reliable track record.