The anticipated timeline for a Block IV upgrade to the F-35 fighter jet may be impacting the Air Force’s decision to slow the procurement of the F-35A variant of the aircraft, according to a newly released report on the future fighter force by The Mitchell Institute for Aerospace Studies. The report says that delays in the delivery of Block IV to 2029 are potentially impacting the service’s delivery and acquisition plans for the aircraft.

“Block 4 is a suite of mostly classified hardware upgrades, technologies, and software drops that radically enhances F-35 combat effectiveness,” according to the study, which is titled Future Fighter Force Our Nation Requires: Building a Bridge. “The F-35 was planned and produced around a concept of spiraling more capabilities into production aircraft.”

Many of the joint strike fighter’s combat capabilities are woven into developmental software increments or “drops,” each increment is designed to advance the platform’s technical abilities. There are more than ten million individual lines of code in its software system.

The Block 3F F-35 software increment, which is now operational, allows the fighter jets to drop a Small Diameter Bomb, five-hundred-pound Joint Direct Attack Munition and AIM-9X short-range air-to-air missile. The AIM-9X is an Air Force and Navy heat-seeking infrared missile.

Delays with Block IV certainly run counter to the Air Force’s fast-evolving software upgrade process. After all, upgrades are accelerating and integrating on much faster timelines to leverage technological advances. Air Force officials have repeatedly explained that software modernization will no longer take place within spread apart, predetermined windows of time often spread apart by a year or more. Instead, they will happen on a more continuous, flowing or “as-ready” basis. This strategy complements the broader software drop trajectory and expedites modernization, security patches, artificial-intelligence-enabled functionality, condition-based maintenance and, perhaps of greatest significance, weapons upgrades. 

Due to some of the more recent software upgrades, the F-35 fighter jet can fire the AIM-9X Sidewinder “off boresight” along with a growing range of weapons. In the next few years, the Block IV will enable the stealth fighter to release the emerging Small Diameter Bomb II, known as the GBU-53/B Stormbreaker.  

Given how important it is to quickly integrate new software to expand weapons and combat functionality, the study cites concerns related to the timeline for Block IV, which will be needed in any kind of confrontation with China.  

“Operational analysis has indicated that the even-more-advanced Block 4 configuration is necessary to be effective in a conflict with China,” the report states. “However, challenges with maturing all of the Block 4 technologies has slid delivery of the full Block IV suite to at least 2029, and this is a significant factor in the Air Force's decision to slow F-35A procurement.”   

Kris Osborn is the defense editor for the National Interest. Osborn previously served at the Pentagon as a Highly Qualified Expert with the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a Master’s Degree in Comparative Literature from Columbia University. 

Image: Flickr / U.S. Air Force