US having "reached out" in 1972 to PRC, the politics of doing so to Brezhnev became possible, and, after Carter's 1/77 inauguration, desirable. The ISTAR and COCOM issues on technology transfer could be fixed - CAAC's 707s, for example, had Litton IN, of clear military pertinence, so the gyro came as a sealed unit, with no repair capability being provided. All Western politicians believed that the evident superiority of (our) products would discomfit the Kremlin and help to defuse domestic propaganda of us as running dogs or worse. The issue causing MDC to baulk, L.1011 notions to be abortive, was money. USSR had none, nor, then was money's substitute, natural gas, available.
XS Deng Opened the Door to Trade, 10/78: that co-incided almost exactly to GPA+ILFC extending to aircraft the freight container concept of operating leasing: they caused capital markets to ignore the (un)creditworthiness of the User and to concentrate on the cash generated by the asset. China chose not to entertain offers of operating lease of Western aircraft, but did accept the pitches, starting in Canton with 737-200ADV, provided they could....buy them for money!!! They would accept whatever operating record-keeping the manufacturer might propose. So the capital markets fell over themsolves to provide loans against Western assets, normal deposits being provided by China. The Party welcomed Western aircraft onto routes into ports where banks could seize them if the User fell into arrears...but they would not, because the tickets were priced in $. Bingo! cascades of everything. Even the Short SD360s were financed on the basis of occasional visits to HKG (and very quickly PRC credit became so good, that ceased to be necessary).
It was not until 1980s that USSR agreed to accept Western finance for aircraft on the basis of Registration in (nearly-proper) places, to ensure record-keeping compatible with high residual values. They all operated routes including ports where they could be seized and which generated sufficient $ to cover their financing.
Oddly, "face" sensitivity was in USSR, not PRC: Sovs. were reluctant to contemplate the economic illiteracy of their products. China had no products.