先看看這段話：
'Structural and avionics/armament upgrades to keep the aircrafts operation were taken into consideration in 1990 and an initial request for information was sent to 10 companies, including Bristol Aerospace, Grumman, Israel Aircraft industries, Singapore Aeroapace and Smiths Industries but all decisions were postponed and later cancelled, pending another request for Lockheed-Martin F-16s. Just limited structural modification/upgrades were performed in the mid-90s to keep the aircrafts operational.'
http://home.eblcom.ch/f5enthusiast/...es/ChinaAF.html

結構的部分有的文件叫SLEP (Structural Life Extension Program)，也可參考http://www.as.northropgrumman.com/p...iger/index.html

另外您有興趣可以請G大神查查'Bonded Honeycomb parts de-bonding moisture intrusion'後，
再想想有多少飛機組件是Bonded Honeycomb parts。(您能放心嗎？)

再就近看看新加坡對F-5 SLEP/upgrade的態度，再想想國內對F-5的處理。

最後
'Unfortunately reliability of the Northrop Tiger has diminished: seventeen single-/double-seaters have crashed between 1988 and 2007, killing 19 officers and leaving 4 pilots missing
There has been a high number of Northrop F-5F losses; in 32 years of active service as of July 2009, 40 have crashed killing 32 pilots, five accidents were between 2005 and 2009. Only 33 remain in service.'