Is a 4 degree glide slope practical ?
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http://www.airnav.com/airport/VNY/ils/16R
http://204.108.4.16/d-tpp/0804/00552I16R.PDF
Van Nuys, California RWY 16R
3.9 degree G/P
Vref is lower on the 727 and 757... so not a big deal. The 737-800, on the other hand, with higher a Vref requires ealier configuration. To add to the fun there is sometimes a tailwind at the onset shifting to a 0 wind about 500 AGL.
http://204.108.4.16/d-tpp/0804/00552I16R.PDF
Van Nuys, California RWY 16R
3.9 degree G/P
Vref is lower on the 727 and 757... so not a big deal. The 737-800, on the other hand, with higher a Vref requires ealier configuration. To add to the fun there is sometimes a tailwind at the onset shifting to a 0 wind about 500 AGL.
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Not so good for those living near the over run area though with all the noise of aircraft running off the end of the runway. ...
Funny, the last time I looked at anything relating to performance, you definitly got a landing dist/mass credit from having a steeper approach angle
Funny, the last time I looked at anything relating to performance, you definitly got a landing dist/mass credit from having a steeper approach angle
. What I was refering to was comming screaming in down the steep slope, not configuring early enough & being too fast at the threshold. I dont think you get any performance credit for that
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On modern aircraft the majotity of the noise is created by interference of slipstream around gear/flaps
If gear noise is that noticeable, wouldn't it be reasonable to consider aerodynamically-shaped strut components in the design phase? Having worked in a different field with drag (simplifying, drag = noise), relatively small engineering changes can have large positive effects.
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I seem to remember the 318 LCY requires the speedbrake to be fully deployed and the gear down prior to the commencement of the approach with the spoilers being used as drag/dump devices in a similar way to the Tristar.
The approach is flown to a double flare with the first being at about 300' to achieve a 'normal' flare at the normal height. (doing this from distant memory so the figures could well be wrong!)
Should be a fun approach after a 2 man night trans atlantic crossing from NY!!!!
The 319 into MRS is no problem at all, 4 deg slope gives you about 1000' per min at the threshold, a gentle progressive flare from 50' is no difficulty.
Please don't 'slipstream' the gear!!!! On a light 319 it is sometimes the only way I can slow the bugger down.
The approach is flown to a double flare with the first being at about 300' to achieve a 'normal' flare at the normal height. (doing this from distant memory so the figures could well be wrong!)
Should be a fun approach after a 2 man night trans atlantic crossing from NY!!!!
The 319 into MRS is no problem at all, 4 deg slope gives you about 1000' per min at the threshold, a gentle progressive flare from 50' is no difficulty.
Please don't 'slipstream' the gear!!!! On a light 319 it is sometimes the only way I can slow the bugger down.
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London City is still a 5.5 degree slope. I think i'm right in saying that someone has recently started operating Airbus 318(?) into there. Must be interesting the first time you do it one of those, it looks odd enough in KingAir nevermind anything bigger! 
As for the 777 and a 4 degree slope being unworkable because the autoland is only certified to 3.25 degrees......can't you hand fly that a/c and actually land it yourself or am I missing something
As for the 777 and a 4 degree slope being unworkable because the autoland is only certified to 3.25 degrees......can't you hand fly that a/c and actually land it yourself or am I missing something
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At easyJet we have recently changed our 'stabilised approach criteria' to reflect the use of higher than 3° glideslopes. In the past it was only permitted to have <1000 fpm rod under all circumstances below 1000'. That has now changed and you can add 150fpm for each 0.5° extra on the glideslope. So at MRS where the glideslope is 4°, you can now accept anything less than 1300fpm as being 'stable'. Obviously you adjust the flare accordingly, but it has taken a lot of the pressure out of these types of approaches and seems a sensible tweak to the rules. I am a previous user of the 5.5° glideslope at LCY, and again as long as you have had the proper training and observed sectors, it is no problem if you follow the correct techniques.
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Airbus limits autoland to 3.15 degrees for A340/A330, however, we do a VOR approach into Kathmandu at 5.8 degress(yes, minus 5.8 degress), at 10 DME, 9500ft and a 4 DME we reduce to 3.5 degrees. We start off at 138 IAS, and sometimes have it increase to 170 on the way down in an Airbus A330. This is not easy, but lots of things are considered, but I would hate to try it on an ILS, as there is no reduction in angle to slow down.
doesn't the shuttle approach on a 25 deg g/s?--thats some energy management---especially considering that most come within +/- 3 knots on the 205 knot Vref and hit the TDZ within 250 ft
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As for the 777 and a 4 degree slope being unworkable because the autoland is only certified to 3.25 degrees......can't you hand fly that a/c and actually land it yourself or am I missing something
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As RNP becomes more widespread a variety of glide slopes could be implemented. Different aircraft could be certified for different glide slopes.
http://en.wikipedia.org/wiki/Require...on_Performance
http://en.wikipedia.org/wiki/Require...on_Performance
Shuttle
Exactly.
20 degrees plus - now that's a man's glide slope.
It took someone of the calibre of Mr Armstrong to sort that one out.
What a ride that would be...
20 degrees plus - now that's a man's glide slope.
It took someone of the calibre of Mr Armstrong to sort that one out.
What a ride that would be...
Below the Glidepath - not correcting
In order to mitigate the noise of arriving aircraft
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I agree with most previous posts. The advantage in terms of noise abatement of a 4 degree glideslope would be minimal - and might lead to an increase in go-arounds.
Berlin/Tempelhof (THF/EDDI) has non-standard slopes too;
ILS 27L: 3.50 degrees / 6.1%, DH (Cat B a/c) 265', RVR 650m
NDB 27L: 3.50 degrees / 6.1%, MDH (Cat B a/c) 757', RVR 1,400m
VOR 27R: 3.70 degrees / 6.5%, MDH (Cat B a/c) 677', RVR 3,000m
The high DH/MDH/RVR values reflect the higher RoD. Runway 27L is 1,840m, 27R is 2,094m.
No big deal on an ATR72, although medium/heavy jets (737-300/700, A320 etc.) have been known to land there sometimes http://www.airliners.net/photo/LTU--...ext_id=1263834
Cheers
Berlin/Tempelhof (THF/EDDI) has non-standard slopes too;
ILS 27L: 3.50 degrees / 6.1%, DH (Cat B a/c) 265', RVR 650m
NDB 27L: 3.50 degrees / 6.1%, MDH (Cat B a/c) 757', RVR 1,400m
VOR 27R: 3.70 degrees / 6.5%, MDH (Cat B a/c) 677', RVR 3,000m
The high DH/MDH/RVR values reflect the higher RoD. Runway 27L is 1,840m, 27R is 2,094m.
No big deal on an ATR72, although medium/heavy jets (737-300/700, A320 etc.) have been known to land there sometimes
http://www.airliners.net/photo/LTU--...ext_id=1263834Cheers
Last edited by FougaMagister; 24th Apr 2008 at 00:00.
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Best to do what they do already and, if it's a steeper than 3.5 degree slope make it a non precision! How much easier is an NDB or VOR approach than a really hard ILS?
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Point is you will have to add some safety margin making the approach even steeper: Like in LCY it's 5.5 degrees plus 2 = 7.5 degrees that you need to be certified for. If you aim at 4 for noise abatement you'll end up close to six in real life certification. That is way steeper than many a/c can handle. There where quite a few mods done to the A318s computers, avionics, callouts, trim, flaps and speedbrakes in order to get it certified for LCY ops.
up to 3.5 degrees - nothing special required, standard certification applies (i.e. 3 deg G/S)
between 3.5 and 4.5 (4.49999999 if you like) - additional requirements for autopilot etc.; no additional requirements for SubPart B (i.e. performance and handling)
4.5 and above - considered "Steep Approach" - additional SubPart B requirements added, including the "+2 degrees" abuse case.
So certifying a 4 degree approach would typically require additional avionics work but generally not much in the way of handling and perf tests, and certainly not the 2 degree abuse case. (That's pretty much the TCCA/EASA approach right now, with the FAA not too dissimilar)
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I think what people mean is that normal Cat III A,B ops is done with the autopilot engaged all the way to roll out (And I am talking in actual condition, not just for the Autoland practice requirement). So if the A/P is not certified then you lose your CAT III ability.