Deep in the Negev desert of southern Israel lies the Shimon Peres Nuclear Research Center, also called the Dimona reactor, the center of Israel’s nuclear research and weapons programs. While its location isn’t exactly top secret, it’s impossible for civilians to get close to it; the Israel Defense Forces have even been known to shoot down their own planes when they don’t have permission to fly over Dimona.
However, while one Israeli Air Force F-35I “Adir” stealth fighter flying over Dimona on Monday wasn’t at risk of being shot down, it did drop its ghostly act for about 20 minutes when it turned on a publicly viewable transponder signal, causing it to appear on civilian radars.
An #IAF F-35I "Adir" revealed around noon its location on @flightradar24 over the Dimona Nuclear Reactor squawking 7600 (Communication Failure). Publication authorized by the Military Censor. Via @ItayBlumental and @Ynetalerts pic.twitter.com/r3URAH0QmG https://t.co/R6fSfvDjXV— Observer IL (@Obs_IL) January 20, 2020
According to Israel’s Ynet News, the Adir was using a “squawk” signal used to communicate certain vital messages on a Mode-S/ADS-B civilian frequency. On Monday, this F-35 was broadcasting Squawk 7600, meaning “transmission error”; other commonly used Squawk codes are 7700, meaning “emergency,” and 7500, meaning “hijacking.”
The Adir, using callsign F35LTNG2 and transponder hex code 738AD2, appeared for about 25 minutes on local radars as well as tracking sites like FlightRadar24 and ADS-B Exchange.
A spokesperson for the IDF told the Jerusalem Post the incident happened "during a routine training flight in a training area in the South,” noting that “a malfunction was discovered in the aircraft's transponder” requiring it to broadcast publicly.
“In order to communicate with the other aircraft that [were] participating in the training, the pilot activated the aircraft's detection system so that the other aircraft would be able to recognize it without communicating with the pilot," the spokesperson said.
As Ynet noted, seeing an IAF plane on any civilian radar, let alone a stealthy F-35 Adir, is “an exceptional event, as Israeli Air Force fighters never operate unencrypted means of transmission.”
Ironically, the IDF spokesperson said the opposite, promising it was “was not an exceptional event” and that "the tracking system is operated at the discretion of the pilot.”
However, still more unusual is that IDF censors permitted images of the F-35, which included it circling over the Dimona facility repeatedly, to be published in the first place, The Aviationist blog noted.
The Aviationist noted that at other times the IAF has purposefully turned on its civilian transponders in order to send a message, as in 2018 when another F-35 suddenly became visible off the Lebanese coast, which might have been a veiled threat aimed at the Hezbollah Lebanese militia. Likewise, US aircraft on patrol over Baghdad following the siege of its embassy there late last year also allowed their locations to be seen by civilian trackers, the blog noted.