Weird thing in the sky? Passing near airliner. Krakow, Poland.

Date: 14 August 2018
Time: 10:35 PM
Clear sky, no moon.

I think I've seen something odd just about an hour ago. After shopping in the nearest city center, as usual, I parked my car near my house. Just a minute after that, suddenly, I've heard a low rumbling sound that lasted for about 2-3 seconds. The sound itself was very loud, and because of that, I was able to localize a "craft" immediately.

It came from East to West just above my head. The first thing that caught my attention was a weird sound that seemed to switch from high to low tones and the impression I had it could be misunderstood as thrust reverse... but it was different. The sound lasted 2-3 seconds and... that was it. Just a silence after that. I used to typical aircraft sounds as I'm working on civilian airport, I've heard plenty engine sounds of various types including jet engines and turboprop engines.

When the "thing" was directly over my head I noticed a light pattern. There were four lights in a row(as along fuselage, I guess) and one light on each side(seems like lights on a wings). It seems there weren't any anti-collision lights. There were no red, green lights on wingtips etc.
Here is a general idea of what I saw:


The picture isn't the thing I saw. I just used it as an example but I tried to show light pattern the best I can. As the aircraft was above me I noticed kind of silent humming sound. But anyway it was as silence as it could be. I think I would not know about "craft" presence but it made that high-to-low tones sound firstly.
What amazes me is that the thing wasn't the only one in the air. There was a passenger jet on approach to nearest airport. I'm using Flightradar24 on my phone and I decided to open app and see if there is any other traffic besides the airliner. There was nothing!
I'll paste here an app screenshot taken about a minute after the sighting. It clearly shows KLM on its way to EPKK.


Blue dot shows my location and there is KL1999 flight. The unknown thing should be on the left from the airliner.
As for the sighting. I'm not sure about the altitude of the thing. I guess it was below 600ft. but I can't be sure. KLM airliner was, I suppose, higher.

I have no idea what it was but I would guess a UAV or drone of some kind. That's the first time when I see something I can't explain. I makes me think now.

Does anyone have heard or seen something similar?

Cheers!

Nice post nice to see someone using their brain a little and checking for any aircraft in the area. I don't have any answers as such but I live just east of London and I'm located under many flight paths one being a busy arrivals path for Heathrow airport, when I start work at 6am I'm usually awake at 5am when the first trickle of arrivals turn up for Heathrow coming in from the east usually long haul flights from Asia (hong kong etc) a nice clear morning it's good to see the A380s and 747s slowly descending into Heathrow

Living under many flight paths I've experienced odd aircraft noises to what I can only describe as what sounds like an aircraft dropping out of warp speed, thats how i describe it anyway or it sounds like the pilot has throttled back from high speed to a slow speed (if that makes sense). For a few seconds it sounds like engines are high pitched then the sound slows to a regular engine noise of a aircraft over head. I put this down to just the sound waves from the aircraft finally catching up to my hearing.

One thing I'd like to add you said the KLM flight and using your screen grab it shows it was about 700ft and you believed the lights were lower. How close would you say the lights were to the KLM flight ? As I'd imagine an aircraft that low and that close to another aircraft and being that close to an airport would of been a big no no in the aviation world. The only thing I can put it down to is maybe a higher aircraft with a strange light pattern. I've seen odd light patterns where an aircraft will have its main lights on (white inner wing lights located where the wing meets the fuselage) and sometimes I've seen aircraft that have lights illuminating the tail section.

Depending on your view point the lighting pattern can resemble something completely different especially at night where your vision cannot make out certain shapes or cannot establish what angle an aircraft is relative to your view point. My best guess is maybe it was a military aircraft at a higher altitude, being military it might not show up on FR24 and the engine noise may of sounded strange due to the sound waves coming from a high altitude to finally being able to be heard by yourself. Like I described in my first paragraph.

Other than that I can't help but good spot and good bit of research on your part for using FR24 and trying to cancel out some possibilities. There's a good website called ADS-B exchange (type it into google) that has filters for some military aircraft, when I spot a aircraft that looks interesting to me if at first I can't find it on FR24 I then go to ADS-B exchange to see if it shows any military aircraft

Star and flag for you for your post and bit of research maybe other members can help out

PS: excuse any punctuation mistakes it's gone midnight here in the UK I'm tired lol

sound that seemed to switch from high to low tones

Maybe - Doppler shift as it passed your position.

a reply to: SpeedFanatic

Why didn't you whip out your phone and record it?

originally posted by: roadgravel

sound that seemed to switch from high to low tones

Maybe - Doppler shift as it passed your position.

That and maybe the increased noise when the flaps first deploy and all that air whistles.

I've seen something almost exactly like the picture you posted, and it has bothered me ever since.

This was a few months ago, March maybe.. driving back to Calgary from Edmonton about 10pm. The craft was in the view front of the truck's windshield, had about 7 white lights along it and the top and bottom.

No blue, red, or green lights, which in the dark contrast of the night sky, looked strange. The lights did not make out a "T" like shape like aircraft with wings/fuselage. The craft was coming in my direction, so in front if me, heading behind me, and there were 5-6 lights on the front, one on the top and one on the top.

It made no noise as I rolled down the window, and was very low. Probably several hundred feet up maybe 1000ft. Bit i doubt that high.

The picture you posted is close to what I saw, bit I couldn't make iut what it was. It was flying NorthWest from SouthEast direction.

a reply to: ThePeaceMaker

Very well written. Thank you for your post.
I didn't know about ADS-B exchange website, I was just using FR24 all the time as it is an app I'm using at work very often. The interesting fact about the sighting was that the "thing" was just coming from slightly different direction than the KLM airliner. But they were very close eachother.

I guess passenger was flying higher than the unknown thing. Radar shows 700ft. for KLM flight but I took the screenshot after a minute or so after the alleged sighting. I'm sure the passenger was a bit higher then 700ft. when it overflew my location. I have to check what altitude is the traffic coming to the airport in the place where I was. My location was about 7km from the airport in straight line.

I think the lights were about 300-400ft. from the KLM airliner. They were on his left side. It's too close for commercial aviation. Maybe the unknown thing was flying higher but then it would mean that it was very big in size. Almost impossible.

Thank you for your input in the thread.

a reply to: SpeedFanatic
I'm surprised you wasn't aware of ADS-B as I've seen you pop in a few other aviation threads but glad I can oss on some helpful input. I didn't know about ADS-B until Zaph mention it.

Like i said I can't provide an answer for you one thing I did think of though perhaps it may of been a small Lear jet type of aircraft and the lights you saw were the internal cabin lights, being a small aircraft it would have fewer windows and being low enough you were able to see the illumination of the cabin. Shorter wings may account for the closer together lights either side

a reply to: SpeedFanatic

You can also go into settings on ADB-S and set filters just for military aircraft. It gets rid of a lot of clutter and you can use FR24 side by side if needed. Of course, it will only show military aircraft if they have their transponders ON, and want to be seen .

a reply to: ThePeaceMaker

Living under many flight paths I've experienced odd aircraft noises to what I can only describe as what sounds like an aircraft dropping out of warp speed, thats how i describe it anyway or it sounds like the pilot has throttled back from high speed to a slow speed (if that makes sense). For a few seconds it sounds like engines are high pitched then the sound slows to a regular engine noise of a aircraft over head. I put this down to just the sound waves from the aircraft finally catching up to my hearing.

What you are describing is spoiler noise. As the aircraft are on finals the auto throttle and flight management system can use a variety of methods to keep a pre-selected speed. Spoilers can deploy and quickly wash off excess speed much faster than cycling the engine throttles which have lag. Also by doing this you can keep the throttles a little higher on power setting which gives you more response if needed as you dont have to wait for as long to spool up. The rising or falling whooshing sound is created by air flowing around the large rectangular slab like spoilers as they cycle up and down fairly rapidly, which on an aircraft like the 747 or A-380 are about the size of a 6-8 place dining table.

a reply to: SpeedFanatic

Aerial sightings are notoriously inaccurate for a variety of reasons. This is even more pronounced at night. This is not a slight on your observation, just a statement in general. Things like size, altitude, speed, orientation and separation are often wildly misjudged.

If the object looked very similar to the pic you posted I think you might have seen a drone along the same sight line as the aircraft you referred to. The drone would appear much larger because it is much closer. The aircraft, being significantly larger but further away, may have appeared to be similar in size giving the illusion the two objects where in close proximity when they really weren't.

The sound you describe sounds exactly like how a drone would be described as it throttled up to slow a descent. And the reason you only heard it for a few moments (and then it disappeared) could be due to the breeze changing the direction of the sound (or eliminating it). A hovering drone is actually surprisingly quiet. I know with mine you can only really hear it when you move it laterally or vertically. The rest of the time it would just blend in with the background noise if you weren't looking for it.

a reply to: thebozeian

Could also be throttle back coming off cruise to final descent.

originally posted by: thebozeian
a reply to: ThePeaceMaker

Living under many flight paths I've experienced odd aircraft noises to what I can only describe as what sounds like an aircraft dropping out of warp speed, thats how i describe it anyway or it sounds like the pilot has throttled back from high speed to a slow speed (if that makes sense). For a few seconds it sounds like engines are high pitched then the sound slows to a regular engine noise of a aircraft over head. I put this down to just the sound waves from the aircraft finally catching up to my hearing.

What you are describing is spoiler noise. As the aircraft are on finals the auto throttle and flight management system can use a variety of methods to keep a pre-selected speed. Spoilers can deploy and quickly wash off excess speed much faster than cycling the engine throttles which have lag. Also by doing this you can keep the throttles a little higher on power setting which gives you more response if needed as you dont have to wait for as long to spool up. The rising or falling whooshing sound is created by air flowing around the large rectangular slab like spoilers as they cycle up and down fairly rapidly, which on an aircraft like the 747 or A-380 are about the size of a 6-8 place dining table.

It's a similar noise to the noise in radio Roberts video or is the same noise, thanks for the clearing that up. I'm still going to pretend it's an aircraft dropping out of warp speed

a reply to: Flyingclaydisk

My bet it was some kind of drone or UAV. However, I know such systems never visits EPKK airport as it is civilian airport. Well, there is military section but it's completely different thing btw. I think the object was flying lower and that made impression of it being in close size to the KLM airliner. I would like to point out that the unknown object wasn't hovering but flew conventionally like normal plane. It headed towards EPKK.
And, of course, I will agree that the thing blended in with the background noise. I was able to hear air rushing.

a reply to: SpeedFanatic


Maybe it's the Pope's new personal jet!

You never know...