An improved probe light assembly for the F-35B and F-35C to enhance visibility for refuelling at night, has completed testing.

The purpose of the probe light on aircraft is to illuminate the refueling receptacle, or ‘basket,’ to ensure that the F-35 pilot can see adequately and make contact to begin refuelling.

According to a news release, the existing lighting design made it difficult for the KC-135 boom operator to see the silhouette of the F-35. One main objective of this redesign is to ensure better visibility for refuelling aircraft.

“An issue with the current probe light was that it was too bright, blinding the KC-135 aerial refueling boom operators,” said Michael McGee, 418th Flight Test Squadron, Aerial Refueling project manager at Edwards AFB.

“The new light was designed to be less bright, but still bright enough for the F-35 pilot to see clearly.”

For this test, an F-35B deployed to Edwards AFB from Air Test and Evaluation Squadron 23, Naval Air Station Patuxent River, and was paired up with a KC-135 and test aircrew from the 418th FLTS. Both ground and flight tests posed interesting challenges for the team consisting of 418th FLTS and 461st Flight Test Squadron personnel.

“For the ground test we used a hangar,” McGee said in a release.

“The environment needed to be completely dark. We had to remove emergency lighting from the facility and place mats on the floor to reduce light glare. The boom operators were raised on a scissor lift to simulate the KC-135 tanker. The team had to simulate the drogue basket approaching the F-35B so the 461st FLTS maintainers mounted the basket onto a B-4 stand.  Since the stand is on wheels, we could simulate the basket approaching the probe while the F-35 pilot assessed the brightness of the light.”

The ground test evaluated two types of lights with different color tones – a warm white light and an amber light – across various brightness levels. The warm white light was assessed as the best choice for both of the boom operators and the pilots.

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Alex T

That’s so high-tech the info. is probably classified…


And I bet it cost millions 🙂

Cam Hunter

Or Billions…..


They really need one of the following so that the hue of the light can be adapted for different situations. Obviously this involves integration with Alexa so expect it to cost… billions 🙂

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Mr Bell

Dimmer switch so the light is adaptable brightness? Or is it an LED and likely to flicker on a dimmer?


On just on a side note if your LEDs are flashing on a dimmer it 1of3
1 non dimmable LEDs
2 you need a leading edge low wattage dimmer
3 if both of the above are fitted you don’t have enough load
Sorry you released the sparky within


Right so couldn’t they filter the part that shines back into the boom operators eyes while keeping the brightness for the F35 pilot? Or are we talking about reflections here.


This is real stealth, f-35 invisible to tanker boom operator from a few metres!p


Put a light sensor on the boom and get it to move towards the light and give the boom operator a book to read?


Hang on a second,
If it’s a probe light, why does it matter about the boom operator being blinded by the light they can close their eyes, it’s the pilots job to hit the basket not the boom operators job to chase the probe.
Although that being said I’m a true believer in K.I.S.S so am dead against the booms existence it’s way to complicated.


Specific use case to the KC-135 when using a drogue refueling receptacle on the end of the center line boom. US Air Force operating procedure is to constantly monitor the proximity of the refueling aircraft (it is a lot closer than with regular hose and drogue operations). More details are available on Trade off between having a bright enough light for the pilot to see the basket but not too bright to blind the operator in the KC-135 depending on various lighting conditions.