Can you ID this Jet noise?

[Joseph II]

I live about 19.5 SSW of Denver Intl. When the weather is VFR, I watch commercial jets cross overhead (west to east) on a left base for the north-south runways at KDEN. They turn final about 2-3 miles east of my house.

My question for all of you is occasionally a jet comes overhead and I hear a very noticeable engine “spool down” noise which I can only describe as the pilots throttling back on the engines considerably. My other thought was that it could be spoilers or flaps being deployed? It sounds something like a “Beeaauuuuuuuuwwwwwwwwwwwwwwwww……” lasting 2-3 seconds.

I hear this maybe once or twice an hour. Any idea what’s going on?

Being 19.5 miles from the airport, I’m not 100% sure how fast the jets are flying and their exact altitude.

Thanks all!

 

[Typhoon1244]

I think what you're hearing is the chemical spray rig being depressurized prior to landing. For security reasons, I really can't say more than that.

Seriously, though...

The engines on the A320 series (operated by Frontier and United, among others) have a very distinctive whine/moan to them. Sounds unlike other U.S. commercial airliners.

That's probably what you're hearing.

Being 19.5 miles from the airport, I’m not 100% sure how fast the jets are flying and their exact altitude.

Probably 250 knots and between five thousand and eight thousand feet. (I'd have to look at the STAR's to be sure.)

 

[bart]

the A320 series (operated by Frontier and United, among others) have a very distinctive whine/moan to them

Is it because they are french?

 

[Typhoon1244]

Is it because they are french?

I thought the engines were British...

 

[mar]

Very good Bart!

That post almost resembled an aviation post.

 

[Typhoon1244]

I thought the engines were British...

After further research, I see they're a joint venture of Snecma (France) and General Electric (you-know-who).

 

[Dizel8]

Well, if it is indeed an Airbi and it is indeed UAL , then it would actually be a IAE V2500 engine and not the CFM. If it is Frontier, NWA, USAir, Apple then it's a CFM.



"Founded in 1983 IAE's shareholder comprise Pratt & Whitney, Rolls-Royce, the Japanese Aero Engines Corporation and MTU Aero Engines, four of the world's finest aero engine manufacturers representing four countries on three continents."

 

[Mogus]

Could it possibly have anything to do with the Doppler Effect?

 

[DenverDude2002]

My question for all of you is occasionally a jet comes overhead and I hear a very noticeable engine “spool down” noise which I can only describe as the pilots throttling back on the engines considerably. My other thought was that it could be spoilers or flaps being deployed? It sounds something like a “Beeaauuuuuuuuwwwwwwwwwwwwwwwww……” lasting 2-3 seconds.

I hear these same noises, although I am 35 NM Northwest of KDEN right under the RAMMS approach. If I'm not mistaken they should be about FL180 overhead at this point. The noise seems to be a lot louder from Frontier A318s and A319s, though sometimes I hear the same noises from the larger Boeing jets (757-777) as well.

 

[skyking1976]

It's a BAe 146. I guarantee it. When you extend the flaps from 0 to 18 degress they make a really weird low-howling noise.

 

[HAZ-MAT]

“Beeaauuuuuuuuwwwwwwwwwwwwwwwww……” lasting 2-3 seconds.

Man, thats pretty much how it sounded a few minutes ago when i dropped the Cosby Kids off at the pool

 

[DenverDude2002]

No I'm sure its Frontier A318/319s, theyre the only planes with those hideous green engines and silver writing on the side ( i liked the old colors a he!!uva lot better). Plus I dont know why any 146s would be using the RAMMS into DEN.

 

[skyking1976]

... I dont know why any 146s would be using the RAMMS into DEN.

RAMMS is not SW of DEN. It would be POWDR/LARKS. Most likely the flight would be ASE-DEN.

 

[DenverDude2002]

Skyking,

I hear the same noises as Joseph only I live under the RAMMS approach 35 miles NW of KDEN. I'm sure the 146's could be what hes hearing but I'm pretty sure the noises I am hearing up here are from A319s and Boeing 757/767 ac. I havent seen a 146 fly on the RAMMS for years.

 

[skyking1976]

I havent seen a 146 fly on the RAMMS for years.

Hmmmm.... there's 5 flights from Eagle that use the RAMMS/TOMSN arrival gate. I understand what the CFM's and IAE V2500 engines sound like. I've been listening to them for quite awhile, mind you. However, The flap noise that the 146 makes is quite unmistakable.

 

[DenverDude2002]

Hmmmm.... there's 5 flights from Eagle that use the RAMMS/TOMSN arrival gate.

Hmm cool. I'll have to keep a look out for them. Is that the main route the 146s are on besides Aspen-Denver?

 

[LR25]

I think what you're hearing is the chemical spray rig eing depressurized prior to landing. For security reasons, I really can't say more than that.

Excellent, excellent!