Entire F-35 Fleet to Get Fix for Engine Vibration Issue

The entire F-35 fleet is slated to get a retrofit its engine manufacturer and the U.S. military say will fix a problem that halted deliveries of the jet for two months. Engine maker Pratt & Whitney has identified the solution, but the move will affect hundreds of fighters globally. 

The decision to make the fix to every fighter in the fleet comes even as both the F-35 Joint Program Office and Pratt say only a “small number” of fighters were actually affected by the problem of “harmonic resonance.” 

The JPO confirmed the retrofits to Air & Space Forces Magazine in a March 2 statement, days after Pratt & Whitney officials told reporters they had identified a fix for the vibration issue identified after an F-35B crash at Lockheed Martin’s Fort Worth, Texas, facility in December. 

The crash, in which the aircraft suddenly pitched forward during a vertical descent and struck the runway, had far-reaching implications as the F-35 JPO stopped accepting deliveries of both the F-35 and its F135 engine and issued flight restrictions for some aircraft, though both the Air Force and the JPO repeatedly declined to specify how many. 

That “small number” of fighters will have to get the retrofit done immediately under the Time Compliance Technical Directive issued by the JPO—once that happens, they’ll be cleared to fly again. 

But it won’t just be that small group that will have to get the fix. The TCTD also directs retrofits for the entire fleet within 90 days, although none of the aircraft will be restricted from flying before getting the fix. 

“While only a small number of aircraft were impacted by the harmonic resonance, the plan is to retrofit the entire fleet, because the retrofit is inexpensive, non-intrusive and supports the JPO’s desire to maintain and manage a single configuration across the entire fleet,” JPO spokesman Russell Goemaere told Air & Space Forces Magazine in a statement. 

Officials have declined to say what exactly the fix will entail. Both Pratt & Whitney and the JPO specified that it can take place at the operational level, outside of depots—but while a Pratt official claimed the fix only takes 30 minutes, Goemaere said in a statement that it takes between four and eight hours to complete. 

F-35 manufacturer Lockheed Martin says it has delivered 890 F-35s over the course of the program, and it has more than 20 other fighters waiting in storage for deliveries to resume—while F135 engine deliveries have been cleared to resume, the fighter itself is still on hold.