Keeping 4th-Gen Fighters in the Game - Air Force Magazine
ttps://www.airforcemag.com/article/keeping-4th-gen-fighters-in-the-game/


>> The aircraft now in the fleet are speed- and load-limited due to stress fatigue in key parts, such as the longerons, Bunch noted.
>> Longerons are major load-bearing structures running alongside the cockpit and connecting the front of the aircraft to the back;
>>they were “life of the aircraft” parts specified to last up to 30 years.
>>The F-15Cs and Ds have exceeded the parts’ life expectancy and replacing them entails virtually dismantling the aircraft.