Among a number of residual issues that remain with the F-35 Joint Strike Fighter, the matter of the jet’s defenses against lightning strikes, or lack thereof, continues to be a particularly vexing issue. For the U.S. Marine Corps and its F-35B variant, thunderstorms are still such a problem that the service is buying special portable lightning rods to help shield the jets when they’re parked outside at bases that otherwise don’t have the necessary infrastructure, which includes Marine Corps Air Station Iwakuni in Japan.
On Aug. 8, 2018, the Marines announced plans to purchase 14 lightning rods through a sole-source contract to LBA Technology, Inc. of Greenville, North Carolina. According to the contracting notice, which the service posted on FedBizOpps, this is the only company that makes systems that the U.S. Military’s main F-35 Joint Program Office has approved for use with the aircraft.
“Since the F-35 as a composite type aircraft does not provide inherent passive lightning protection, the lightning rods being requested are needed for deploying aircraft to any expeditionary airfield in support of combat operations or training exercises that do not support all lightning protection requirements for the F-35B,” the Marine Corps said in its justification for giving the deal straight to LBA. “Based upon extensive research from the F-35 Joint Program Office, this is the only lightning rod that meets the established program requirements.”
Based on the Marines’ minimum requirements, LBA’s F-35-specific version of its PLP-38-MOB rod can remain upright even in winds of up to 120 miles per hour without needing to be moored to the ground in some fashion. They can also operate in spite of heavy rainfall, ice buildup, or extreme hot and cold temperatures. It is not clear how much each one costs, but a complete PLP-38-MOB kit has a unit price of $18,750, according to LBA’s website.
But from the information that is available, we know the lightning protection is absolutely vital if the Marine Corps expects to park its F-35Bs out in the open at bases such as Iwakuni and avoid the hassle of having to move them into hangars or under other suitably protected shelters every time there is the possibility of a thunderstorm. As of 2017, the plane’s manufacturer Lockheed Martin was still finalizing improvements to the Autonomic Logistics Information System (ALIS) to properly shield it against the shock of a lightning strike across all variants, according to a routine report from the Pentagon’s Office of the Director of Operational Test and Evaluation, also known as DOT&E.
ALIS is the F-35’s central computer brain, which supports virtually every aspect of its operation from tracking and isolating maintenance issues and the ordering of spare parts to the uploading and downloading a host of mission and sensor data. You can read more about how it functions in more detail here and here. Suffice to say, if the system fails, the jets would be effectively non-functional until technicians could get it up and running again.
However, there is a far more serious issue linked to the Joint Strike Fighter’s main fuel tank. Combined with the aircraft’s lack of inherent lightning strike protection, it is difficult and complicated to make the fuel system “inert” once the plane is on the ground.
What this means is that there is a distinct potential for a build-up of both oxygen and fuel vapors inside fuel tank that could be dangerous by itself. If a bolt of lightning were to hit a non-inert plane on the ground, there could be an increased risk that it would set off an explosion or cause a fire.
The problem appears to be especially pronounced on the B model, which features a significantly different internal arrangement from the A and C variants due to the need for a large lift fan assembly. This is an essential component of the jet’s a short and vertical takeoff and landing capability.
“The [F-35B] aircraft does not maintain residual inerting after flight for the required interval of 12 hours, which is a lightning protection requirement,” DOT&E reported in 2015. “If the residual inerting cannot be improved, aircraft maintainers will be required to purge fuel tanks with external nitrogen more frequently or alternative lightning protection strategies (e.g., lightning-protected shelters), will have to be adopted.”
The next year, DOT&E reported that the F-35 program had made progress on resolving the inerting issue on the B variant, but that some deficiencies remained. There is no mention of inerting the fuel system in any of the subsequent routine reports on the Joint Strike Fighter from the Pentagon’s top testing office. This could imply that all of the parties involved had decided that the issue was resolved or that any pertinent information is now classified.
Still, the lightning rod purchase shows that regardless of any improvements to the Marine Corps’ jets, the service decided to implement “alternative lightning protection strategies,” as well. It’s not clear whether the issue has already hampered Marine F-35B operations from Iwakuni since Marine Fighter Attack Squadron One Two One (VMFA-121) first deployed there with its Joint Strike Fighters in 2017.
In 2016, VMFA-121 had to cancel a number of F-35B sorties during the Red Flag 16-3 training exercise at Nellis Air Force Base in Nevada over concerns about lightning strikes, according to official records we at The War Zone obtained via the Freedom of Information Act. A month before, thunderstorms, combined with concerns about the inerting issue, temporarily shut down Air Force F-35A operations at Mountain Home Air Force Base in Idaho during a separate drill involving the rapid deployment aircraft from the 388th Fighter Wing at Hill Air Force Base in Utah.
Concerns about mixing the F-35 with lightning have persisted since then, too. In March 2017, the Royal Australia Air Force kept two F-35As at Avalon Airport near Melbourne for an extra day after an air show over fears about lightning strikes. Poor weather delayed the historical arrival of the first Royal Air Force F-35Bs to the United Kingdom, though the U.K.’s Ministry of Defense insisted that this was a routine precaution that would’ve applied to any aircraft.
But regardless of whether or not the safeguards to shield the F-35 against lightning strikes have truly mitigated the issue, the need for lightning rods is a reminder that it remains a serious concern, even at more established bases such as Iwakuni. Deploying F-35s of any type has already proven to be challenging logistically given the complexities of maintaining the aircraft’s stealthy coatings and other advanced features.
The need for portable lightning rods only adds another component, along with added costs, to the deployment package necessary to support Joint Strike Fighters during expeditionary operations. This could be even more pronounced when U.S. military, or other F-35 operators, try to make use of bare bases or other austere facilities to quickly disperse the jets during any future conflict or contingency.
This is an important selling point for the B model, with its short and vertical takeoff and landing ability, in particular. The only alternatives to deploying lightning protection systems with the jets would be to make potentially expensive upgrades to any facility that might host Joint Strike Fighters or preposition portable lightning rods and any other necessary equipment at those sites.
It appears that the Marine Corps has determined that lightning rods are a practical means of setting up lightning protection for its F-35Bs during overseas deployments and expeditionary operations, at least among the options available. Whether or not they can demonstrate that it is a truly a practical means of shielding the jets, especially during short-notice deployments, will be an important test for future Joint Strike Fighter operations around the world.
If nothing else, it’s another good reason for pilots to call the jets by their new nickname, Panther, instead of their official moniker, Lightning II.
Contact the author: jtrevithickpr@gmail.com