Development of China's C919 single-aisle plane, already at least five years behind schedule, is going even slower than expected, a dozen people familiar with the program said as the state-owned Commercial Aircraft Corp. struggles with technical issues that have severely restricted test flights.
Delays are common in complex aerospace programs, but the especially slow progress is a potential embarrassment for China, which has invested heavily in its first serious attempt to break the hold of Boeing and Airbus on the global jet market.
The most recent problem came down to a mathematical error, according to four people with knowledge of the matter.