Hi Mutt....I have no experience with the G3 so I cant help you there unfortunately.

But as an example, the initial pitch for a GLEX is 17 degrees which is quite high in itself. Following the V2 +10-20 profile will give a pitch attitude substantially higher than this. Combine low weights, isa...blah blah bla, it can be pretty scary for unseasoned pax.

Deck angle
 

I don't know, maralinga, but it sounds more like fun to me. Then again, you're quite right - the CEO and his mistress in the aft cabin might not find it so unless properly briefed in advance.

So, how much (approximately) does the new GLEX deck angle change atwixt MTOM and say 8000 lbs less at V2+10 vs. V2+20, say at ISA?

Also, you wrote that the higher deck angle was a "great way to point the engines at the noise monitors", and I suppose you're suggesting an increased deck angle may increase the noise level over that of a flatter climb. Is that just intuitive, or do you know of evidence to that effect?

Either way, I do appreciate your inputs.

Bests,

Tom

I don't have the airplane manuals in front of me, but from memory I seem to recall that sideline noise levels and such measured at certification based on SOP flight profiles as set forth by certification for climb performance, etc. If those numbers exceeded the airport noise levels...seems reduced thrust departures, if safe, possible, might be the next 'tool' to use...personally I'd consider telling the boss, 'do you want a high deck angle or a noise fine'...which would probably lead to a discussion, options, and the obvious solutions. Reduced power, high deck angle...

Hi RainingLogic. I agree reduced thrust TO (flex thrust, etc.) will certainly reduce noise. From a non-certification or operational level, however, sideline noise is (I believe) almost never measured because that measurement must be at THE point of highest noise, laterally 450 meters away. So, for an airport authority, it would be impractical to decide where along the takeoff path to actually put the microphone(s) for different aircraft.

I am more concerned about the takeoff or flyover measurement taken at 6500 meters from brake release and the effect reduced weight has upon it. Naturally, the higher the altitude (read: further away because of better climb) the airplane is at that point, the lower the noise. (Even though it has at least been inferred in this thread that a higher deck angle may increase noise somewhat. I'm not sure there's evidence of this).

So, let me summarize in statement form some of what those responding to this thread have indicated. Please anyone, copy and correct any of these if you can confirm, if you disagree or have something to add:

A. Given all engine climb (AEO) at V2+10, both the deck angle and climb angle will increase as will climb rate compared with a same configuration climb at V2.

B. Given all engine climb (AEO) at V2+20, both the deck angle and climb angle will increase as will climb rate compared with a same configuration climb at V2+10.

C. AEO deck angles at V2+10 or V2+20 will be excessive, or at least may be uncomfortable for PAX.

D. V2 varies with weight, but A thru C above are still valid.

Remember we're talking about a twin engined biz-jet in the Gulfstream class. Thoughts welcomed.

Cheers,

Tom

Noise monitoring at LGW
 

Many years ago:

I was busted for exceeding the permitted noise levels at LGW.

The formal letter arrived, and we were invited to the airport noise monitorint office at the airport, to explain why we exceeded the levels, and be prepared to pay the fine.

No quite sure why on PA28 (140, not even a 180) managed to exceed even a 1-11's scream, but the monitor man did laugh, and decided that our fine was cancelled.

As I understand it the monitor did not filter any frequencies, and our little puddle jumper had a spike in its audio spectrum.

Was also invited one day to discuss why we did not follow the SID / Min noise when operating between Gatport and Redhill.....

glf

Fortunately I haven't had to deal with noise issues, haven't been in the plane/airport combination to have this consideration.... But it reminds of guys I knew looking for jets for their boss, passing on 5 million dollar GIIs for 20 million dollar GIVs mainly because of noise abatement issues and some nod to range, even though they never took the plane anywhere with more then a half tank on board. I found it funny that some weak pilot could get some very smart guy, who's DNA is wired for making money, to part with $15 mil. more then he had to, because no one asked the question: 'So why don't we go to the airport three minutes away that doesn't have noise abatement?' Or - 'Why don't we drop a half mil. on a hush kit? or 'Why do you have to do an F16 carrier departure?

I know in the states, there is only a few airports that will actually fine you. Most of them just send you a nasty gram...