Northbound turboprops March 4th
 

Around 1230 today a turbo-prop trundled northbound across UK Home Counties/Midlands, about FL120ish. It had that 'Antonov' sound. It was followed about ten minutes later by another, then ten minutes after that, another one. Then first one slid briefly through a gap in the clouds - it didn't look big enough for an AN12, but was a bit far off to be sure. Nothing showed up on FR24 or NATS ae.

Anyone know what they were?

RAF A400M ?

There were 2 USAF C130 flights several minutes apart midmorning overhead us here in Kent flying northeast. Did not show on Flightradar24, but did on ADSBexchange. My guess you saw these.

Yes, there were actually three.I couldn't see them, but I followed them on ADSB. They seemed noisier than usual (maybe because of atmospherics?) and I thought the first one was an Antonov, which was why I checked with ADSB

Thanks for the replies; so it was the C130s then.

Now off to Specsavers....

I had the same experience and HAD to check what was making the noise ;-) Must've been atmospherics, as they were much louder than normal.

In my experience, the ubiquitous C-130J is quite a bit less noisy than the legacy T-56 powered C-130H and earlier. All 3 of yesterday's were the latter.

Interesting. I was at Heathrow yesterday and some time around mid-day I too heard these noises. They were quite loud but not visible due to the scattered cloud. To be honest, after I found I couldn't see anything, I put it down to either noise coming from Heathrow or even heavy traffic on the A30!