Altitude for legal super sonic flight?

[NJA_Capt]

NJA_Capt, you're quoting AINonline over the FARs?

Are sonic booms really that loud if the aircraft is at altitude?

I could be wrong, however. I'm just going off of what I've been told.

1. The FARs were already quoted. It doesn't get much more clear than...
(a) No person may operate a civil aircraft in the United States at a true flight Mach number greater than 1 except in compliance with conditions and limitations in an authorization to exceed Mach 1 issued to the operator under appendix B of this part.

2. Yes, aircraft at altitude make a noticeable boom. See previous references to overpressure comparisons with the Concorde and DARPA. Please keep in mind we aren't talking about the "nuisance" of 1 civilian boom incident. We are talking about fleets of supersonic aircraft. There are currently 300 Citation Xs on the market. Could you imagine if those 300 a/c were operating supersonic?

3. You are quoting "things you heard" vs. me quoting an Aviation Publication?

The point is. Outside of flight test and military ops, supersonic flight over the US is prohibited.

 

[Blip16]

i remember an airshow when i was a kid, maybe early 90's and there were sonic booms, it was freaking cool. if it has been outlawed since '68 how was that possible?

 

[Scandinavian13]

1. The FARs were already quoted. It doesn't get much more clear than...
(a) No person may operate a civil aircraft in the United States at a true flight Mach number greater than 1 except in compliance with conditions and limitations in an authorization to exceed Mach 1 issued to the operator under appendix B of this part.

2. Yes, aircraft at altitude make a noticeable boom. See previous references to overpressure comparisons with the Concorde and DARPA. Please keep in mind we aren't talking about the "nuisance" of 1 civilian boom incident. We are talking about fleets of supersonic aircraft. There are currently 300 Citation Xs on the market. Could you imagine if those 300 a/c were operating supersonic?

3. You are quoting "things you heard" vs. me quoting an Aviation Publication?

The point is. Outside of flight test and military ops, supersonic flight over the US is prohibited.

1. The FAR says "except," so it's not completely prohibited. You then attemped to rebut someone's statement by using something other than the FARs, when he used the FARs, which I found to be odd. That was my only point.
The FARs are the rule of the land, and if it says "except in compliance with conditions and limitations in an authorization," it's not simply prohibited.

2. Thanks for the clarification. My question was more along the lines of "would it be a nuissance at altitude, in terms of volume or palpable disturbance?"

The few times the Space Shuttle landed at Edwards in the 90s the booms were quite loud, shook the windows a lot too.

That answers the question to some degree. I didn't think that an aircraft at 450-600 would produce enough of a wave to disturb that much.

3. I'm sorry. There isn't a rulebook or glossary of comparative sound events by decibel describing the sonic boom of supersonic flight readily available to me. I questioned you quoting an aviation publication over the FARs because the FARs were pertinent to the conversation. An aviation publication over things I've heard are about the same in caliber, since there's no official guidebook that sets out how much of a nuissance the supersonic events would be. It's all opinion. If I was arguing it wasn't a nuissance, backed by hearsay, over someone arguing it would be, backed by dB data with comparitive volume levels, that would be a similar case.


Sorry. I wasn't trying to tear you to shreds or anything, I was just curious why someone would quote an aviation publication in one's defense, over the FARs.
I do agree with you, though; for all intents and purposes civilian supersonic flight is prohibited, to take it simply. The exceptions wouldn't be useful for any application, and the FAA wouldn't readily grant a waiver for any civilian reasons.

 

[NJA_Capt]

Sorry. I wasn't trying to tear you to shreds or anything, I was just curious why someone would quote an aviation publication in one's defense, over the FARs.

It's more curious that a person with a PPL is questioning the motives of someone who is flying the fastest production aircraft in the world, for a company with a vested interest in getting the FAR changed. Sorry that you don't see things as black and white as I do. It is very evident to those of us on this site who that have been in this industry 20+ years, that people tend to interpret the FARs the way they "want" to see it, or in ways they perceive can benefit them or their viewpoint. I was offering an unbiased, third party viewpoint supporting the FAR. The speed limit is 65, that's the law. But the police can exceed 65. That doesn't mean the speed limit isn't 65.
https://www.faa.gov/about/office_or...ersonic_noise/media/2-Panel5-Smith-NetJet.pdf

Overpressure
Sonic booms are measured in pounds per square foot of overpressure.
This is the amount of the increase over the normal atmospheric pressure which surrounds us (2,116 psf/14.7 psi).

At one pound overpressure, no damage to structures would be expected.

Overpressures of 1 to 2 pounds are produced by supersonic aircraft flying
at normal operating altitudes. Some public reaction could be expected
between 1.5 and 2 pounds.

Rare minor damage may occur with 2 to 5 pounds overpressure.

As overpressure increases, the likelihood of structural damage and stronger
public reaction also increases. Tests, however, have shown that structures
in good condition have been undamaged by overpressures of up to 11 pounds.

Sonic booms produced by aircraft flying supersonic at altitudes of less than
100 feet, creating between 20 and 144 pounds overpressure, have been experienced by humans without injury.

Damage to eardrums can be expected when overpressures reach 720 pounds.
Overpressures of 2160 pounds would have to be generated to produce lung damage.

Typical overpressure of aircraft types are:

SR-71: 0.9 pounds, speed of Mach 3, 80,000 feet
Concorde SST: 1.94 pounds, speed of Mach 2, 52,000 feet
F-104: 0.8 pounds, speed of Mach 1.93, 48,000 feet
Space Shuttle: 1.25 pounds, speed of Mach 1.5, 60,000 feet, landing approach
http://www.nasa.gov/centers/dryden/news/FactSheets/FS-016-DFRC.html

http://www.faa.gov/about/office_org...ersonic_noise/media/1-panel4-magee-boeing.pdf

 

[SFCC/UND]

Lets say you can, but you might not have your license when you get back on the ground. There problem solved.

 

[Barty]

The few times the Space Shuttle landed at Edwards in the 90s the booms were quite loud, shook the windows a lot too.

But I really don't think the designers really cared about the boom, either

One of the Shuttles came in rather low over the Atlanta area back in 2000 or 2001 and produced a nice boom that was audible where I lived at the time. Evidently the weather at Kennedy was iffy and so they put them on a track that gave them the option of landing at Robbins AFB south of Macon if need be, which is one of the alternate landing sites for the Shuttle.

It had been such a long time I had heard a sonic boom that I just went "what was that??" when I heard it. Last time I heard a boom was in the late 80s out in Utah at Bryce Canyon NP, from some military overflights.

 

[Scandinavian13]

It's more curious that a person with a PPL is questioning the motives of someone who is flying the fastest production aircraft in the world, for a company with a vested interest in getting the FAR changed.

I'm not sure what relevance my PPL has to this conversation. If you're using it as evidence that I'd have less aviation knowledge, it's a valid argument. True, I don't have nearly as much training and book work as you, yet, but I do have equal access to the regs and I have read them.

I wasn't questioning motives. I was curious as to why someone would quote an aviation publication over the FARs. That's it. It was benign, really. I'm sorry if you felt that I was trying to put you down for it.

Sorry that you don't see things as black and white as I do. It is very evident to those of us on this site who that have been in this industry 20+ years, that people tend to interpret the FARs the way they "want" to see it, or in ways they perceive can benefit them or their viewpoint. I was offering an unbiased, third party viewpoint supporting the FAR. The speed limit is 65, that's the law. But the police can exceed 65. That doesn't mean the speed limit isn't 65.

Laws are not black and white, FARs are not black and white. Sure, there are some laws that are very black and white, but many are not in order to allow for situations unseen by the lawmaker to be determined by a judge or board. Yes, this FAR is pretty darn black and white, but there is an attached shade of grey. There's quite literally no chance of taking advantage of it, because a waiver would be nearly impossible to obtain, but the grey is there and that's all I'm trying to point out.

Typical overpressure of aircraft types are:

SR-71: 0.9 pounds, speed of Mach 3, 80,000 feet
Concorde SST: 1.94 pounds, speed of Mach 2, 52,000 feet
F-104: 0.8 pounds, speed of Mach 1.93, 48,000 feet
Space Shuttle: 1.25 pounds, speed of Mach 1.5, 60,000 feet, landing approach
http://www.nasa.gov/centers/dryden/news/FactSheets/FS-016-DFRC.html

http://www.faa.gov/about/office_org/headquarters_offices/aep/supersonic_noise/media/1-panel4-magee-boeing.pdf

Perfect. That's what I wanted to know. Thank you.
Based on that, I would agree with you that multiple events per day could be considered a nuissance.