The Japanese air force, navy and coastguard have a future requirement for regional aircraft to replace their ageing fleets of NAMC YS-11 turboprops.
Japanese authorities acknowledge there is a need to start replacing the assets, say industry sources involved in the sale of regional aircraft.
"There is some small movement in the ministry of defence to phase out the YS-11s," says one. "I don't know when they plan to phase out the YS-11s, but the physical condition of the aircraft will decide it."
The aircraft's age means that purchasing spare parts is a problem, the source adds.
Constraints on Japan's defence budget mean the purchase of a YS-11 replacement is unlikely to be included in the next fiscal year from April 2011, industry sources say.
Flightglobal's MiliCAS database says the average age of Japan's YS-11 fleet is 40 years. The air force has 13, the navy 10 and the coastguard three, it adds.
The YS-11 is a 64-seat turboprop built in the 1960s and early 1970s by Nihon Aircraft Manufacturing, which has since folded.
Mitsubishi Aircraft has a sales team dedicated to pitching the MRJ regional jet to the government. Other possible contenders include the ATR 42/72, Bombardier's Q-series and secondhand Saab turboprops.