Steep Approach into LCY
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Steep Approach into LCY
Sorry if a repeat, but I wonder if someone could explain why some smaller jets can make it into LCY, but others can't?
I know the 146 makes it, but what has it got that others don't? Also, I read that Embraer want to send the 170 into LCY. The 146 I can get, but not the 170.
Any other bigger jets that can make it with sesible payloads?
I know the 146 makes it, but what has it got that others don't? Also, I read that Embraer want to send the 170 into LCY. The 146 I can get, but not the 170.
Any other bigger jets that can make it with sesible payloads?
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The A318 has recently been certified to fly into LCY - certainly the biggest!!
It has come at a price though with airbus designing a 'steep approach' function into the machine (probably comes as an option during ordering).
There is a 'steep approach' button on the overhead which changes the various FBW law's to enable a safe steep approach.
Certain spoiler panels on the wing automatically deploy on approach to allow for a stable speed/high rate of descent. They then automatically retract on short final.....and re-deploy fully as normal on touch down.
Impressive!!
It has come at a price though with airbus designing a 'steep approach' function into the machine (probably comes as an option during ordering).
There is a 'steep approach' button on the overhead which changes the various FBW law's to enable a safe steep approach.
Certain spoiler panels on the wing automatically deploy on approach to allow for a stable speed/high rate of descent. They then automatically retract on short final.....and re-deploy fully as normal on touch down.
Impressive!!
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The A318 trials in May were successful, I recall..
Not sure whether these were trials in simulated conditions at Toulouse or actually at LCY, but I'm sure a search of the flight international archive would bring up the article I read at the time. I remember reading a more detailed paper from this summer's IALPA conference, also. I'm fairly sure I found the paper on wingfiles.com, nerd that I am, but I can't find it right now. In brief, and from memory ..
Airbus have managed to achieve this "steep approach" capability for the A318 essentially by special programming of the Fly-by-wire Flight Control System. To achieve a speed-stabilised steep approach (and to demonstrate this at even steeper approach angles than the LCY glideslope), some of the speedbrake panels are partially extended during the approach. This reduces lift and so Vref is increased (to Vls+8 kts). It seems that lots of things happen behind the scenes with the control computers, including changes to the gains in the autothrottle, AOA protection, roll authority and flare laws.
However, Airbus claim to have made it as straightforward as possible for the crew. Evidently additional simulator training is required at Toulouse, and the aircraft monitors all of the various mode selections and modified control laws [as I understand it, in a similar manner to the "autoland" warning function, ...any malfunction leading to a mandatory go-around (unless there are mitigating circumstances, eg a fire). Standard call out heights are substantially modified as are rules for GPWS activation, etc, due to higher rates of descent.
The interesting bit as I recall is the flare, as retracting the spoilers would cause a float and leaving them extended makes for a bit of a firm arrival, so there is some sort of compromise where they are retracted from 30 degrees to a lesser angle, and of course all fully deployed as usual after touchdown. The flare is initiated much higher than normal, due to the steeper approach angle and higher rate of descent.
So there are modified SOPs and some new skills involved, though I think I read that the steep approach, once armed and activated, can still be "hand-flown", Airbus-stylee, using the "bird" (Track/Flight Path Angle selected on Primary Flight Display). I remain mightily impressed by the capabilities of the airbus FBW aircraft, and the A318 (together with the new Embraers) will surely open up new possibilities from LCY and new sales for an aircraft that, hitherto, didn't really have an unique selling point.
[ed...windshear beat me to it, more succinctly]
Airbus have managed to achieve this "steep approach" capability for the A318 essentially by special programming of the Fly-by-wire Flight Control System. To achieve a speed-stabilised steep approach (and to demonstrate this at even steeper approach angles than the LCY glideslope), some of the speedbrake panels are partially extended during the approach. This reduces lift and so Vref is increased (to Vls+8 kts). It seems that lots of things happen behind the scenes with the control computers, including changes to the gains in the autothrottle, AOA protection, roll authority and flare laws.
However, Airbus claim to have made it as straightforward as possible for the crew. Evidently additional simulator training is required at Toulouse, and the aircraft monitors all of the various mode selections and modified control laws [as I understand it, in a similar manner to the "autoland" warning function, ...any malfunction leading to a mandatory go-around (unless there are mitigating circumstances, eg a fire). Standard call out heights are substantially modified as are rules for GPWS activation, etc, due to higher rates of descent.
The interesting bit as I recall is the flare, as retracting the spoilers would cause a float and leaving them extended makes for a bit of a firm arrival, so there is some sort of compromise where they are retracted from 30 degrees to a lesser angle, and of course all fully deployed as usual after touchdown. The flare is initiated much higher than normal, due to the steeper approach angle and higher rate of descent.
So there are modified SOPs and some new skills involved, though I think I read that the steep approach, once armed and activated, can still be "hand-flown", Airbus-stylee, using the "bird" (Track/Flight Path Angle selected on Primary Flight Display). I remain mightily impressed by the capabilities of the airbus FBW aircraft, and the A318 (together with the new Embraers) will surely open up new possibilities from LCY and new sales for an aircraft that, hitherto, didn't really have an unique selling point.
[ed...windshear beat me to it, more succinctly]
Last edited by George Foreman; 13th Oct 2006 at 05:16. Reason: sp, ed
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You can find an Airbus Powerpoint Presentation "A318 steep approach operation" on Wingfiles:
http://www.wingfiles.com/files/liais...18steepapp.pps
Robert
http://www.wingfiles.com/files/liais...18steepapp.pps
Robert
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One feature that the 146/RJ has is a huge airbrake on the tail. This is deployed at glideslope capture and must be operational for an approach into LCY. On other aircraft e.g. EMB145 you could only use airbrake upto the first stage of flap.
It allows us to make an approach at approx 55%N1 caompared with 65%N1 for a 3 degree ILS.
I remeber reading somewhere on here that to certify an aircraft for steep approaches that the engine speeds have to a certain proportion of either idle thrust or normal approach thrust, but cannot remember. It makes sense though - you don't want to have idle thrust with 1000fpm fully configured.
Our a/c have steep approach buttons and I'm sure that all they do is desensitive the GPWS/EGPWS. They cost about £500 to install.
It allows us to make an approach at approx 55%N1 caompared with 65%N1 for a 3 degree ILS.
I remeber reading somewhere on here that to certify an aircraft for steep approaches that the engine speeds have to a certain proportion of either idle thrust or normal approach thrust, but cannot remember. It makes sense though - you don't want to have idle thrust with 1000fpm fully configured.
Our a/c have steep approach buttons and I'm sure that all they do is desensitive the GPWS/EGPWS. They cost about £500 to install.
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The approach limitation, I believe, means that the aircraft has to demonstrate a stabilised, still-air 7.5 degree capability before it is allowed to do the 5.5 degree slope required at LCY. Not a lot of jets can do that. The A318 went to LCY a few months ago to prove the software works and achieve certification and now Airbus will be looking for customers who require a greater payload or range out of LCY. Have heard that a well known Dutch company who fly to LCY are looking for a Fokker 50/70/100 replacement...
There are three significant items that define an aircraft’s ability to make a steep approach and landing. These are given in JAR certification requirements, but in technical terms.
On the approach, the aircraft must be capable of maintaining the steep glidepath in the most limiting configuration e.g. engines spooled up for anti-icing. The aircraft must demonstrate that there is a further 2 degree margin on the approach to provide maneuver capability; maneuver ‘agility’ is also assessed – the quickness in being able to regain the flight path. These parameters are limited by the aircraft’s drag margin – the ability to maintain a constant speed approach in the chosen configuration, thus the use of full flap/airbrake. The maneuver ability depends on control, mass, inertia, and many aerodynamic design issues.
The second item is the ability to flare and touchdown - the ability (amount and quickness) to use the available wing lift to change the flight path. This comes from good wing lift characteristics (good lift-slope gradient, generally slower speed STOL aircraft), and the elevator effectiveness. It may be necessary to balance quick change of lift and the loss of speed during flare, i.e. where wing spoilers are used to add drag for the approach they might reduce the lift available in the flare and add to the speed loss. This in turn may have to be offset by an increased approach speed (cf A318), which then affects landing distance and operating weight.
The third item is the ability to stop in the distance available. This is not necessarily associated with steep approaches, but normally a steep approach is only used into limiting runways, thus the economics of the operation have to be considered.
Other aspects include a demonstration of a landing from Vref -5, a single engine landing and go-around, good flight deck visibility, EGPWS changes, etc.
Flight tests determine the aircraft’s capability which can vary between variants e.g. BAe146-100/200 has a 6 deg clearance, but the 146-300 only has 5.5 degs and a tailwind limit.
renard the steep approach button (IIRC) also changes the FD/Autopilot control laws (146 a GS sensitivity change, but the RJ uses time/RA?)
On the approach, the aircraft must be capable of maintaining the steep glidepath in the most limiting configuration e.g. engines spooled up for anti-icing. The aircraft must demonstrate that there is a further 2 degree margin on the approach to provide maneuver capability; maneuver ‘agility’ is also assessed – the quickness in being able to regain the flight path. These parameters are limited by the aircraft’s drag margin – the ability to maintain a constant speed approach in the chosen configuration, thus the use of full flap/airbrake. The maneuver ability depends on control, mass, inertia, and many aerodynamic design issues.
The second item is the ability to flare and touchdown - the ability (amount and quickness) to use the available wing lift to change the flight path. This comes from good wing lift characteristics (good lift-slope gradient, generally slower speed STOL aircraft), and the elevator effectiveness. It may be necessary to balance quick change of lift and the loss of speed during flare, i.e. where wing spoilers are used to add drag for the approach they might reduce the lift available in the flare and add to the speed loss. This in turn may have to be offset by an increased approach speed (cf A318), which then affects landing distance and operating weight.
The third item is the ability to stop in the distance available. This is not necessarily associated with steep approaches, but normally a steep approach is only used into limiting runways, thus the economics of the operation have to be considered.
Other aspects include a demonstration of a landing from Vref -5, a single engine landing and go-around, good flight deck visibility, EGPWS changes, etc.
Flight tests determine the aircraft’s capability which can vary between variants e.g. BAe146-100/200 has a 6 deg clearance, but the 146-300 only has 5.5 degs and a tailwind limit.
renard the steep approach button (IIRC) also changes the FD/Autopilot control laws (146 a GS sensitivity change, but the RJ uses time/RA?)
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Boost to A318 Sales?
I notice from the Airbus website that they only have 90 orders for the 318. LCY capability must give them a good chance of boosting that number, I don't think anyone else is in the 100-120 pax class? Range must be much improved over the 146.
I take it that some of the Fokker jets operate out of LCY?
One thing that sparked my curiosity on this topic was an article I remember reading in Flight 2 or 3 years ago about a big airbrake that Embraer were going to put in their belly fairing on the 170. It looked quite a piece of equipment. I think it was related to the Swissair order they had which was related to LCY ops and they needed it to get the drag for the approach. I've had a close look at a couple of E170/175s on the ground, but I see no evidence of it or any obvious place to put it. Are they managing to get into LCY without it and if so, how?
Will we see a day where the LCY apron is full of 146s, F70s, A318s and E170s?
I remember watching the A-Team a few years ago and seeing a scene with a biz-jet (Challenger?) with the thrust reversers cracked open for a pretty impressive descent rate. Would that work for a steep approach?
I take it that some of the Fokker jets operate out of LCY?
One thing that sparked my curiosity on this topic was an article I remember reading in Flight 2 or 3 years ago about a big airbrake that Embraer were going to put in their belly fairing on the 170. It looked quite a piece of equipment. I think it was related to the Swissair order they had which was related to LCY ops and they needed it to get the drag for the approach. I've had a close look at a couple of E170/175s on the ground, but I see no evidence of it or any obvious place to put it. Are they managing to get into LCY without it and if so, how?
Will we see a day where the LCY apron is full of 146s, F70s, A318s and E170s?
I remember watching the A-Team a few years ago and seeing a scene with a biz-jet (Challenger?) with the thrust reversers cracked open for a pretty impressive descent rate. Would that work for a steep approach?
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STOL approaches
I operated the DHC5-D Buffalo for many years and it was quite normal to make STOL (of short field approach/landing) on a 7.5 degree approach. I cannot think of any reason ANY aircraft could not achieve that except a structural thing ie the tail striking the ground on touch down. The Buff has a very steep rear end but even so the round out is pretty minimal basically just land it FLAT.
However the CAA have had a 'thing' about STOL performance aircraft - I can remember years ago when the Dornier 228 first appeared on the scene the Germans had it certified for STOL approaches and take offs but the CAA whinged and moaned until it was basically killed stone dead.
C (Campaign ) A (Against) A (Aviation) strikes again !
Of course it takes a good set of hands and a steady eye to make a good STOL approach (remember Farnborough and the ex RAF Marshemellows attempt ?) so there are lots of pilots out there probably not up to it!! (Yes very controversial I know but true!)
However the CAA have had a 'thing' about STOL performance aircraft - I can remember years ago when the Dornier 228 first appeared on the scene the Germans had it certified for STOL approaches and take offs but the CAA whinged and moaned until it was basically killed stone dead.
C (Campaign ) A (Against) A (Aviation) strikes again !
Of course it takes a good set of hands and a steady eye to make a good STOL approach (remember Farnborough and the ex RAF Marshemellows attempt ?) so there are lots of pilots out there probably not up to it!! (Yes very controversial I know but true!)
The larger aircraft are now benefiting from the lengthening of the runway beyond 1199m. Although the F70/100 could land at LCY, the operating economics were poor. The longer runway enables more passengers and/or more fuel for greater range, thus the appearance of the A318. The BAe 146-200 could operate a good (full?) load to and from Florence and the Crossair RJ100, 85 business class (heavy bar and food) to and from Zurich. I emphasis to and from destination airports as not all aircraft had this capability.
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correct me if I'm wrong guys, but I believe the A318 actually has fewer seats than the RJ100.
It might take 90-100 odd people a bit further then an RJ, but where exactly would you park the baby Bus? The stands just barely fit the RJ at the moment.
I sit awaiting correction
It might take 90-100 odd people a bit further then an RJ, but where exactly would you park the baby Bus? The stands just barely fit the RJ at the moment.
I sit awaiting correction
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Partly answered my own question at this website:
http://www.lcacc.org/index.html
From the site:
Aircraft currently approved for scheduled services
Here are brief details of the principal types of aircraft currently approved for use at the the Airport to provide scheduled services. (Note: The Maximum Take off and Landing Weights of aircraft are not always available at London City Airport).
ATR 42
BAe 146/Avro RJ family
BAe 4100 Jetstream
DHC-6 Twin Otter
DHC Dash 7
Bombardier Q Series/DHC Dash 8
Dornier Fairchild 228 Embraer 135
Dornier Fairchild Do328
Fokker 50
Fokker 70
Saab 340
Saab 2000
Shorts 360-300
So, no Fokker 100 and no E170, or any Bombardier RJs for that matter.
And for info, the A318 is quoted at 107 pax, RJ100 at 100-112.
at this website:http://www.lcacc.org/index.html
From the site:
Aircraft currently approved for scheduled services
Here are brief details of the principal types of aircraft currently approved for use at the the Airport to provide scheduled services. (Note: The Maximum Take off and Landing Weights of aircraft are not always available at London City Airport).
ATR 42
BAe 146/Avro RJ family
BAe 4100 Jetstream
DHC-6 Twin Otter
DHC Dash 7
Bombardier Q Series/DHC Dash 8
Dornier Fairchild 228 Embraer 135
Dornier Fairchild Do328
Fokker 50
Fokker 70
Saab 340
Saab 2000
Shorts 360-300
So, no Fokker 100 and no E170, or any Bombardier RJs for that matter.
And for info, the A318 is quoted at 107 pax, RJ100 at 100-112.
All this retro-fitting of aircraft with add-on bits of flap etc to make steep approaches and short runways seems a bit dodgy to me! (e.g. 318 at LCY and 738 at SDU)
I'm sure its all legal and safe but it just doesn't seem right! Just an opinion.
I'm sure its all legal and safe but it just doesn't seem right! Just an opinion.
