I live on the line connecting GSP to ATL, so there are many planes (and helicopters, and the rare blimp) that fly pretty much directly above me. Minutes ago, someting is flying over. Unseen, but from the sound seemed to be a large-ish passenger jet. Normal sounds, at first. But then the sound increased exponentially very suddenly, sounding like a rocket launching and nearly loud enough to be painful. After probably less than 5 seconds it returned to normal, and then a number of seconds later it did it again for maybe 10 seconds, a loud roaring sound almost like rolling thunder, or a car constantly backfiring. That time it went on for maybe 10 seconds before clearing up. I don’t recall ever hearing something like that before, and I honestly wondered if it was going to crash.
Back when the Air National Guard had a fighter wing here, the pilots doing training would hot-rod the take off and go into a steep climb as soon as they could get the wheels up. Then they’d taper off and set course. Normal/loud/normal/loud pretty much describes the sound they made.
BTW, this was headed from the direction of ATL to GSP, and about 20 miles out from GSP.
My guess is that the pilot was using the speed brakes to slow the plane down for landing. From what I understand they can be quite noisy.
I live and work near Chicago O’Hare (ORD) and have noticed some exceptionally loud takeoffs. I’ve come to associate it with rainy or at least overcast weather.
The OP’s description doesn’t really fit with speed brakes or other typical passenger jet noises. They tend to make airflow noises, howls, whines, and so on. It sounds more like a military jet at high power. The multiple times might be because there were several of them. I’ve never heard a compressor stall, but they’re supposed to sound like a series of loud bangs like a car backfiring.
Here’s a video with the sound of a stalling engine:
If it didn’t sound like that, then I’m going with military jet/s at high power.
No, nothing like that. Imagine like I mentined, something akin to a rocket (as in NASA) launch.
And it seemed pretty low and slow, like you would expect with a jet 20 miles from landing.
Two possibilities.
Request from the tower to quickly increase altitude for some reason. Or other maneuver that required power increase.
Strong winds changing directions that alternately brought the sound to you better a couple of times.
Why would a modern multi-spool engine have compressor stalls? Also, the speed brake looks like it’s floating in some kind of auto trim mode. can that be turned off?
Compressor stalls would be a symptom of an engine failure of some sort, definitely not normal. The spoilers “floating” are roll spoilers working with the ailerons.
That was my thought. If some other aircraft was getting too close, or an excursion occurred that required an aborted landing or quick change in altitude then most modern jets can blast pretty hard.
My thought too. Either a missed approach (unlikely, unless the weather was especially bad), or a “go-around” command from the tower (a plane stuck on the runway, for example).