[Question] How to land a 6-degree glide slope

[TChapman500 0]

I've built a custom airport that has a few obstacles near the runway, requiring a glide slope of ~6 degrees to clear them. How do I run that glide slope without accelerating above my target speed? Standard glide slope appears to be ~3 degrees, so I'm coming down at double the normal speed.

 

So far, I've run the landing twice (both in A321 fully loaded), both with a starting speed of about 135 kts, and both times I ended up landing at around 170 kts with one of those landings collapsing the left landing gear. Is there anything I can do apart from removing fuel that will prevent the aircraft from accelerating so much? Due to the steep glide slope, approach altitude is around 3,000 feet.

[Sekstifire 10]

It appears that you need a STOL aircraft, like for example the Avro RJ, for such landings. You do of course need to be fully configured for landing (flaps down, gear down) before you intercept the LOC, or at least before you start following the GS down to the threshold

[fisheye 3]

Are you using the spoilers on approach? San Diego's Lindberg Field is also a steep approach and they don't have any problems.

[Sekstifire 10]

One should not use the spoilers with the flaps deployed

[TChapman500 0]

I have resorted to using spoilers to slow the aircraft down. In my first two flights, I did not use spoilers, but in my last flight, I did use spoilers. In fact, I had both spoilers and wheel brakes engaged before I hit the runway. And I still landed (I think this time at 175) too fast.

 

A couple more things to point out, the runway is only 5,000 feet in length, and it's a commercial airport right in the middle of the infield of a race track with a ~60-foot obstacle (31-degree track surface banking plus 30-foot catch fence) 1,200 feet from the end of the runway.

 

PS: I'll post a video of the landing.

 

EDIT: Unable to make video of landing.

[Johnny767 40]

Realistically speaking...In order to land and airlner on a runway, you must also have an airport runway with a reasonable lenght. eg. 6,000 ft and above. And, with that inclination, yes, somethng that heavy will build more speed...Not sure long is your runway. And, of course there may other factors that will influence.

[TChapman500 0]

The runway is 5,000 feet in length (as already mentioned) and 11 feet above sea level, less than half of a degree from the equator and international date line. I can take off from the runway just fine fully loaded with the A321 and 737-800 (which is the largest aircraft the airport is designed to handle).

[ryanbatc 13,036]

I'd use full flaps and gear down of course... 6 degrees is quite steep. I'd have autobrakes set to max if you've got them and spoiler to arm. You'll probably be at idle speed...

 

Think of it this way, whatever your ground speed is, add a zero to the end and you'll end up with (roughly) the fpm descent you'll need to achieve a 6 degree glide path.

 

Example... at 140 kts you'll need to descend @ -1400 fpm assuming a 6 degree glide path.

 

This isn't a perfect mathematical equation but a standard glide path is 3 degrees (such as an ILS etc) and for that you half your ground speed and add a zero to find required descent rate.

[coa1117 53]

Realistically speaking...In order to land and airlner on a runway, you must also have an airport runway with a reasonable lenght. eg. 6,000 ft and above

 

Not really accurate. Take a look at the chart for the ILS rwy 09 at EGLC (London City Airport). It's a 5.5 degrees glideslope, with runway length = 4948'. Airbuses routinely land there, although I think I read that the 73x series is not yet certified. It's quite a fun approach to fly, but make sure you are fully configured before you capture the glide.

[ryanbatc 13,036]

Not really accurate. Take a look at the chart for the ILS rwy 09 at EGLC (London City Airport). It's a 5.5 degrees glideslope, with runway length = 4948'. Airbuses routinely land there, although I think I read that the 73x series is not yet certified.

 

Agreed... I've seen a C17 land where I work... our secondary runway is 5700ft... and he was turning off the taxiway about 2500 ft down - it was incredible. Ok a C17 isn't an airliner but it is a huge beast. There's many variables to calculate a safe runway length...

[CoolP 283]

Airbuses routinely land there

I think it's Airbuseses. Wait. Wrong thread. :o

[coa1117 53]

I think it's Airbuseses. Wait. Wrong thread. :o

 

Umm .. who can even pronounce that? :)

 

FTW:

 

World English Dictionary bus (bʌs) — n , pl buses, busses

[McLaren 42]

Are you using the spoilers on approach? San Diego's Lindberg Field is also a steep approach and they don't have any problems.

 

The Lindberg app. angle (as advertised on the localizer 27 plate) is 3.14 degrees, I.E. its steep, but not that bad.

[CoolP 283]

Umm .. who can even pronounce that? :)

I have to apologize. I was just referring to a previous thread, joking about the plural of Airbus. Alan's vote was even better.

 

By the way, it's interesting that they did not have to modify the actual 'hardware' of the A318 to be able to land at EGLC. All they've added was an extra mode to be activated prior to the approach. http://www.flightglo...on-city-206570/

[Art_P 6]

 

 

Agreed... I've seen a C17 land where I work... our secondary runway is 5700ft... and he was turning off the taxiway about 2500 ft down - it was incredible. Ok a C17 isn't an airliner but it is a huge beast. There's many variables to calculate a safe runway length...

 

Speaking of short runways for the C-17:

http://www.ksn.com/content/news/also/story/Oops-Wrong-airport/JTFTuESfck2UCxeWgSL7Ng.cspx