The actual maintenance of the F-22 actually involves scraping the RAM material that was installed on the surface of the aircraft and removing the fastener bolts that came out, one by one. The above video and images were taken by the F-22 maintenance crew at Tyndall Air Force Base.
First, the F-35 has the following markings on the bolt that removes the regular access panel. There are fan shaped white marks around the bolt, and the bolt itself is shaped like an embedded hexagonal bolt hole. The same is true for the panel on the right side of the cockpit where the pilot's ladder is housed.
The hexagon bolt holes appear to be flat against the fuselage and the surface of the bolts. This part may be a pusher-type mechanism that retracts only when the bolts are turned.
That this part is a stationary access panel is known from the news on November 30, 2017, when an F-35A landed at Kadena Air Base and dropped the access panel. The news (NNN) of the F-35B that landed at Kadena Air Base shows that this is the part of the aircraft that can be used as a constant access panel without having to remove the RAM sheet.。
F-35B access panel (lower left side of nose) and enlarged view of the bolt
（©Orbit Seals）
The F-35A fighter whose access panel has fallen off
The pilot's ladder compartment is also marked the same as the access panel
（©Orbit Seals）
It is marked FWD MASTER LATCH (7/32 HEX) and AFT MASTER LATCH (7/32 HEX), and it looks like it can be removed normally with a 7/32" Allen wrench.
Next, fastener bolts can be seen throughout the fuselage of the F-35B. This is the same as the YF-23 and F-22. However, the F-35B differs from the other models in that there are additional bolts to fill the holes in the fastener bolts.
Shown below as an example are the fastener bolts on top of the F-35B fuselage. It is viewed from the side, so you can clearly see the tolerances of the bolts. If you zoom in, you can see that some of the holes have been filled and others have been left unattended. The hole-filling bolt has a smaller bolt in it, which can be fixed with a hexagonal wrench, judging from the shape of the hole in the center.
F-35B upper fuselage fastener bolts（©Orbit Seals）
Enlarged view of the F-35B fastener bolt（©Orbit Seals）
The fastener bolts seem to encapsulate a smaller, lighter gray bolt that can be used to seal the recessed space between the bolt holes. You can see from the pictures above that some of them are blocked by smaller bolts, some are not, and some are slightly skewed and distorted, and some have broken bolts.
Why some have bolts to fill the bolt holes and others don't is unclear (do they fill them during the mission?). To achieve a higher level of stealth, a new fastener bolt design, not found on the YF-23 or F-22, has been introduced.
The following diagram shows the different bolt configurations used on the F-35B.
There are three types of bolts used on the F-35B: a standard bolt, a high stealth bolt, and a bolt with RAM applied on top of it, which seems to offer more variation than the F-22.
Three types of fastener bolts in the F-35B（©Orbit Seals）
5．Stealth Fighter Fastener Bolt Comparison
Stealth Fighter Fastener Bolt Comparison（©Orbit Seals）
Based on the information so far, I've compiled a comparison of stealth fighter fastener bolts above. Note that the F/A-18E is based on images taken separately by the author and is not a pure stealth fighter.
Comparing them, the F-35B, F-22, and YF-23 appear to be almost identical in construction, although the YF-23 has a lower resolution. The F-22 and F-35B, in particular, were manufactured by the same company, Lockheed Martin stealth fighters, so it is not surprising that their structures are similar.
What sets the F/A-18E apart from the others is that the F/A-18E's bolts have six wavy shapes exposed on the surface of the fuselage that connect to the driver.
The YF-23 is unknown due to its low resolution (but the exposed portion of the fuselage surface is a round-hole shape pattern), but both the F-22 and F-35B bolts have a new circular round-hole shape at the same height as the fuselage surface.
On the other hand, if you look inside the holes in the F-35B's bolt, and inside the F-22's screwdriver and bolt holes, you can see a silvery, shiny metal tooth pattern; the connection to the screwdriver, like the F/A-18E, appears to be a six-hole shape.
The fastener bolts appear to be unique to the stealth aircraft, although the screwdriver/instrument used to tighten the bolts is similar to that used on conventional fighters. The fastener bolts used on the F-35B and F-22 have a new circular bolt entry at the same level as the fuselage surface, and are thought to engage and rotate with the screwdriver connection due to the six teeth present inside.
In the F/A-18E, the six wave-shaped teeth run continuously from the entrance to the back of the bolt hole, but in the F-35B and F-22, the entrance is a gaping hole that allows the driver to move away from the screwdriver and engage with the internal metal teeth, allowing the bolt to rotate.
This is probably because they did not want to expose the fuselage surface to the discontinuity of the F/A-18E in terms of radar reflection. And the F-35B has even its bolt holes filled in by smaller bolts, and the hexagonal wrench? It appears that a new type of fastener bolt that can be fastened with a screw is used.
The F-35B and F-22 bolts appear to have larger heads than the F/A-18 bolts, although the number of samples is small. It is about three times larger than the center bolt hole; the F/A-18's would be about twice as large or less. I wonder if this area also has something to do with the design to obtain low RCS.
But these hole-filling bolts, not only on the top of the F-35B's fuselage, but also on the underside of the nose of the jet engine in front of the air intake. The ones that were used on the top of the fuselage are at an angle, about to come off, or actually come off, as far as I can see in the photos? Some of them had cracks in them.
I was very worried that it might come off during the flight, but they must be very confident about how to fix it in front of the air intake. Or is it plastic with RAM painted on the surface?
F-35's air intake and enlarged view of the hole-filling bolts used in front of the air intake
6．Maintenance of the F-35
