I need help identifying this.

[GKABS]

I'm curious about those red and yellow cylindrical objects that are sticking out. From the warning label on the photo ('CAUTION / DO NOT REMOVE THIS CAP / POWER SUPPLY'), it looks like they’re protective caps for electrical connectors. The red and yellow colors typically help identify various electrical systems or voltages, making sure the right caps go back on the right connectors. So, my question is: how do they come out from the jet? Do they pop out by being pushed, or is there another method? Or were they attached by the ground crew, maybe using some sort of magnet?

[Muesli]

I did an internet search and it says this:

 

These are mechanical indicators that visually signal the status of critical systems to ground personnel during pre-flight checks or maintenance:

• Orange Protrusions: These typically indicate the status of the M61 20mm Vulcan cannon and its firing systems. Specifically, if the Gun Electric or Gun Holdback safety pins are removed, the orange indicators will be visible.
• Yellow Protrusions: This is the safety indicator for expendable countermeasures (chaff and flares). When the safety pin is pulled to arm the system, a yellow indicator will protrude.

[GKABS]

Thank you for the information  

[GKABS]

Further information how they work:

They protrude (pop out) before taking off and remain protruding during the entire flight.

Here is the precise sequence:

1. On the Ground (Pre-Flight / Maintenance)

· Condition: The safety pins are INSERTED.

· Indicator Status: The orange and yellow pins are FLUSH (pushed in, hidden in the fuselage).

· Meaning: The gun and countermeasures are SAFE (mechanically locked).

2. Arming the Aircraft (Before Engine Start or Taxi)

· Action: The ground crew or pilot pulls the "Remove Before Flight" flags.

· Indicator Status: The spring-loaded orange and yellow pins POP OUT and remain sticking out from the fuselage.

· Meaning: The systems are ARMED (ready for combat).

3. During Flight and Landing

· Indicator Status: The pins remain PROTRUDING the entire time the aircraft is flying. The airflow does not push them in; they are mechanically locked in the "out" position by internal springs.

· Visual Cue for Landing Signal Officer (LSO): As the jet comes in to land, the LSO actually looks for these protruding pins. If an LSO sees the orange pin is flush (missing) during a recovery, that is a major safety hazard — it means the gun might be unsafe and the pin was never removed.

4. After Shutdown (Post-Flight)

· Action: The ground crew re-inserts the safety pins.

· Indicator Status: The pins are pushed BACK IN flush with the fuselage.

Summary Mnemonic

· Pins IN = Indicators IN (Safe/Flush)

· Pins OUT = Indicators OUT (Armed/Protruding)

P.s. but I am confused as I didn't notice that before!