An F-35 Lightning II performs a maneuver Sept. 12, 2016 over Luke Air Force Base, Ariz.

An F-35 Lightning II performs a maneuver Sept. 12, 2016 over Luke Air Force Base, Ariz. U.S. Air Force / Senior Airman Devante Williams

F-35 Program Completes Band-Aid Fix for Engine

All jets had received the modification earlier this month, but the Pentagon is still trying to figure out why a mysterious vibration is happening.

The Pentagon has finished modifying its F-35 jets to prevent catastrophic engine damage, and expects by June to take delivery of all the aircraft and engines delayed by a December crash.

The F-35 Joint Program Office paused flight operations and the acceptance of new jets after a December crash in Fort Worth, Texas, and a subsequent investigation revealed a vibration, or  “harmonic resonance,” that causes the jet’s fuel tube to fracture. A viral video of the crash showed an F-35B bouncing off the ground and spinning around before the pilot safely ejected. Defense News reported that an F-35 engine also failed during a pre-delivery test due to a similar vibration problem in March 2020—almost three years before the December mishap.

Earlier this year, the program began fitting F135 engines with an “orifice” that “reduces the impact to loss of engine control” if the fuel tube “fractures as a result of the harmonic phenomenon,” F-35 Program Executive Officer Lt. Gen. Michael Schmidt told lawmakers at a March 29 hearing of the House Armed Services tactical air and land forces subcommittee.

The Pentagon is still trying to figure out why the vibration occurs and how to prevent it, Schmidt said.

All U.S. F-35s had received the fix by early May, JPO spokesperson Russ Goemaere said in a statement. 

“The hardware mitigation is fully implemented on all F-35 aircraft presented for government acceptance. The majority of backlogged aircraft are accepted to date. The collective government and industry team will continue to work through the remaining backlog to deliver high quality aircraft,” Goemaere said. 

The program expects to have the backlog fully cleared by early June “pending completion of acceptance flights and artifact review for government acceptance,” Goemaere said. 

Installing the fix is a “simple process,” Schmidt testified at the March hearing. 

Pratt & Whitney resumed engine deliveries on Feb. 17, and Lockheed Martin resumed aircraft deliveries on March 14. 

“This government and industry collaboration will ensure incorporation of multi-stepped mitigation efforts that will fully address this rare phenomenon in F135 engines. Meanwhile, root cause identification and analysis of this failure mechanism will continue,” Schmidt said.

As the Pentagon continues to investigate the F135 engine problems, the number of U.S. F-35s ready for duty remains lower than the goal of 70 percent for F-35As and 75 percent for the B and C models. In April, the mission-capable rate for all U.S. F-35s was 56 percent, Schmidt said in an April statement. 

“Our deployed/combat coded fleet significantly exceeds this average,” he said. 

JPO declined to explain why readiness is down “due to operational security concerns,” but said it has “dedicated degrader action cells” assigned to each of the main problems reducing F-35 mission capability. 

Schmidt said the program aims to increase mission capability and bring the average up to 64 percent by next April. 

The Air Force intends to upgrade its existing Pratt engines through a program called engine core upgrade, or ECU, having rejected a proposal to pursue a new engine. Service officials have said the upgrade will restore engine life and prevent degradation for all three F-35 variants “at the lowest cost.”

X
This website uses cookies to enhance user experience and to analyze performance and traffic on our website. We also share information about your use of our site with our social media, advertising and analytics partners. Learn More / Do Not Sell My Personal Information
Accept Cookies
X
Cookie Preferences Cookie List

Do Not Sell My Personal Information

When you visit our website, we store cookies on your browser to collect information. The information collected might relate to you, your preferences or your device, and is mostly used to make the site work as you expect it to and to provide a more personalized web experience. However, you can choose not to allow certain types of cookies, which may impact your experience of the site and the services we are able to offer. Click on the different category headings to find out more and change our default settings according to your preference. You cannot opt-out of our First Party Strictly Necessary Cookies as they are deployed in order to ensure the proper functioning of our website (such as prompting the cookie banner and remembering your settings, to log into your account, to redirect you when you log out, etc.). For more information about the First and Third Party Cookies used please follow this link.

Allow All Cookies

Manage Consent Preferences

Strictly Necessary Cookies - Always Active

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Sale of Personal Data, Targeting & Social Media Cookies

Under the California Consumer Privacy Act, you have the right to opt-out of the sale of your personal information to third parties. These cookies collect information for analytics and to personalize your experience with targeted ads. You may exercise your right to opt out of the sale of personal information by using this toggle switch. If you opt out we will not be able to offer you personalised ads and will not hand over your personal information to any third parties. Additionally, you may contact our legal department for further clarification about your rights as a California consumer by using this Exercise My Rights link

If you have enabled privacy controls on your browser (such as a plugin), we have to take that as a valid request to opt-out. Therefore we would not be able to track your activity through the web. This may affect our ability to personalize ads according to your preferences.

Targeting cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites. They do not store directly personal information, but are based on uniquely identifying your browser and internet device. If you do not allow these cookies, you will experience less targeted advertising.

Social media cookies are set by a range of social media services that we have added to the site to enable you to share our content with your friends and networks. They are capable of tracking your browser across other sites and building up a profile of your interests. This may impact the content and messages you see on other websites you visit. If you do not allow these cookies you may not be able to use or see these sharing tools.

If you want to opt out of all of our lead reports and lists, please submit a privacy request at our Do Not Sell page.

Save Settings
Cookie Preferences Cookie List

Cookie List

A cookie is a small piece of data (text file) that a website – when visited by a user – asks your browser to store on your device in order to remember information about you, such as your language preference or login information. Those cookies are set by us and called first-party cookies. We also use third-party cookies – which are cookies from a domain different than the domain of the website you are visiting – for our advertising and marketing efforts. More specifically, we use cookies and other tracking technologies for the following purposes:

Strictly Necessary Cookies

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Functional Cookies

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Performance Cookies

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Sale of Personal Data

We also use cookies to personalize your experience on our websites, including by determining the most relevant content and advertisements to show you, and to monitor site traffic and performance, so that we may improve our websites and your experience. You may opt out of our use of such cookies (and the associated “sale” of your Personal Information) by using this toggle switch. You will still see some advertising, regardless of your selection. Because we do not track you across different devices, browsers and GEMG properties, your selection will take effect only on this browser, this device and this website.

Social Media Cookies

We also use cookies to personalize your experience on our websites, including by determining the most relevant content and advertisements to show you, and to monitor site traffic and performance, so that we may improve our websites and your experience. You may opt out of our use of such cookies (and the associated “sale” of your Personal Information) by using this toggle switch. You will still see some advertising, regardless of your selection. Because we do not track you across different devices, browsers and GEMG properties, your selection will take effect only on this browser, this device and this website.

Targeting Cookies

We also use cookies to personalize your experience on our websites, including by determining the most relevant content and advertisements to show you, and to monitor site traffic and performance, so that we may improve our websites and your experience. You may opt out of our use of such cookies (and the associated “sale” of your Personal Information) by using this toggle switch. You will still see some advertising, regardless of your selection. Because we do not track you across different devices, browsers and GEMG properties, your selection will take effect only on this browser, this device and this website.